Sex Chromosome Aberrations
Sex Chromosomes
Chromosome Aberrations
Chromosomes
Chromosome Mapping
X Chromosome
In Situ Hybridization, Fluorescence
Chromosome Banding
Y Chromosome
Sister Chromatid Exchange
Chromosomes, Human
Aneuploidy
Chromosome Disorders
Sex Chromosome Disorders
Chromosome Painting
Chromosomes, Human, X
Chromosomes, Human, Pair 1
Micronucleus Tests
Chromosomes, Human, Y
Mutagenicity Tests
Chromosomes, Human, Pair 11
Cytogenetics
Chromosomes, Human, Pair 7
Chromosomes, Plant
Cytogenetic Analysis
Translocation, Genetic
Silene
Chromosomes, Human, Pair 13
Mutagens
X Chromosome Inactivation
Corneal Wavefront Aberration
Chromosomes, Human, Pair 18
Americium
Lymphocytes
Mosaicism
Chromosomes, Artificial, Bacterial
Chromosomes, Human, Pair 21
Chromosomes, Human, Pair 17
Metaphase
Chromosome Breakage
True hermaphroditism associated with microphthalmia. (1/546)
A 4-year-old boy with an undescending left testis, penoscrotal hypospadia and bilateral microphthalmia was admitted to our hospital. Chromosome analysis revealed a karyotype of 46, XX del(x)(p2 2,31) and the sex-determining region of the Y chromosome (SRY) was negative. The right testis was located in the scrotum and a left cystic ovary-like gonad, a salpinx and a unicorn uterus were found in the left inguinal canal. Histologically the gonad was an ovotestis in which primordial follicles covered infantile seminiferous tubules. Microphthalmia is observed in some congenital syndromes caused by interstitial deletion of the X chromosome. This case suggested that the short arm of the X chromosome was involved in the differentiation of the gonad. Very closely located follicles and infantile seminiferous tubules indicated that induction of meiosis in the fetus was controlled by the local microenvironment in follicles and seminiferous tubules, and not by the systemic hormonal condition. (+info)Triple X female and Turner's syndrome offspring. (2/546)
A mentally retarded young female having 47 chromosomes with a triple X karotype produced a child with Turner's syndrome associated with mental defeciency. To our knowledge this is the first example of a triple X female giving birth to a child with Turner's syndrome. (+info)Asynchronous replication of alleles in genomes carrying an extra autosome. (3/546)
Transcriptional activity of genes appears to be highly related to their replication timing; alleles showing the common biallelic mode of expression replicate highly synchronously, whereas those with a monoallelic mode of expression replicate asynchronously. Here we used FISH to determine the level of synchronisation in replication timing of alleles in amniotic fluid cells derived from normal foetuses and from those with either of the trisomies for autosomes 21, 18 or 13, or for sex chromosomes (47,XXX and 47,XXY). Two pairs of alleles, not associated with the extra chromosome, were studied in subjects with each trisomy and three in normal subjects. In cells derived from normal foetuses and from foetuses with sex chromosome trisomies, each pair of alleles replicated synchronously; yet these very same alleles replicated asynchronously in cells derived from foetuses with trisomy for any of the three autosomes studied. The results suggest that the gross phenotypic abnormalities associated with an extra autosome are brought about not only by over-expression of genes present in three doses, but also by modifications in the expression of genes present in the normal two doses. (+info)Investigation of a unique male and female sibship with Kallmann's syndrome and 46,XX gonadal dysgenesis with short stature. (4/546)
A sibship is described where the brother and a sister both have Kallmann's syndrome (anosmia and deficiency of gonadotrophin releasing hormone) and the woman also has streak ovaries. Although there are several conditions that may occur with Kallmann's syndrome, there are no known reports of ovarian dysgenesis being associated with this disorder. Cytogenetic analysis showed no rearrangement or major deletions of the chromosomes. Linkage analysis using informative microsatellite markers predicts that a gene other than KAL1 (at Xp22.3) is implicated in the Kallmann's syndrome manifesting concurrently with ovarian dysgenesis found in this family. (+info)Maternally inherited cardiomyopathy: clinical and molecular characterization of a large kindred harboring the A4300G point mutation in mitochondrial deoxyribonucleic acid. (5/546)
OBJECTIVES: The purpose of this study was to describe the clinical and molecular features of a large family with maternally inherited cardiomyopathy (MICM). BACKGROUND: Recently, several mitochondrial deoxyribonucleic acid (mtDNA) point mutations have been associated with MICM. However, the distinctive clinical and morphologic features of MICM are not fully appreciated. This is partially due to the small size of the reported pedigrees, often lacking detailed clinical and laboratory information. METHODS: Clinical and genetic analysis of the family was carried out. RESULTS: Echocardiography showed mostly symmetrical hypertrophic cardiomyopathy in 10 family members. The illness had an unfavorable course. Progressive heart failure occurred in three subjects, who eventually died; one individual underwent heart transplantation. Electrocardiographic or echocardiographic signs of cardiac hypertrophy in the absence of significant clinical complaints were observed in five subjects. Neurologic examination was normal. The mutation was detected in blood from all available subjects. Abundance of mutated molecules ranged between 13% and 100% of total mtDNA genomes. The severity of the disease could not be foreseen by the proportion of mutation in blood. CONCLUSIONS: This report contributes a better description of the clinical aspects of MICM and provides important clues to distinguish it from hypertrophic cardiomyopathy. We suggest that mtDNA mutations, particularly in the transfer ribonucleic acid for isoleucin, should be systematically searched in patients with MICM. The identification of an underlying maternally inherited mitochondrial DNA defect in familial cases of cardiomyopathy may considerably influence the management and genetic counseling of affected patients. (+info)Developmental and genetic disorders in spermatogenesis. (6/546)
The most common cause of male infertility is idiopathic. Fresh insights based on genetic and molecular analysis of the human genome permit classification of formerly unexplained disorders in spermatogenesis. In this article, we review new procedures that expand diagnostic and therapeutic approaches to male infertility. Recombinant DNA technology makes it possible to detect specific chromosomal and/or genetic defects among infertile patients. The identification of genes linked to disorders in spermatogenesis and male sexual differentiation has increased exponentially in the past decade. Genetic defects leading to male factor infertility can now be explained at the molecular level, even though the germ cell profile of infertile patients is too variable to permit classification of the clinical phenotype. Increasing knowledge of genes that direct spermatogenesis provides important new information about the molecular and cellular events involved in human spermatogenesis. Molecular analysis of chromosomes and/or genes of infertile patients offers unique opportunities to uncover the aetiology of genetic disorders in spermatogenesis. Increasing numbers of cases, previously classified as idiopathic, can now be diagnosed to facilitate the treatment of infertile men. Advanced knowledge also poses ethical dilemmas, since children conceived with assisted reproductive technologies such as intracytoplasmic sperm injection (ICSI) are at risk for congenital abnormalities, unbalanced complements of chromosomes and male infertility. (+info)Type and frequency of chromosome aberrations in 781 couples undergoing intracytoplasmic sperm injection. (7/546)
Cytogenetic investigations were performed in 781 couples prior to intracytoplasmic sperm injection (ICSI) because of severe male infertility or fertilization failures in previous in-vitro fertilization attempts. Out of these 1562 patients, 1012 had a normal karyotype without any aberrations (64.8%), 204 patients had an abnormal karyotypes (13.1%). These chromosome aberrations included constitutional aberrations (4.4%), fragile sites of autosomes (3.0%), low level mosaicism of sex chromosomes (4.0%) and secondary structural chromosome aberrations (4.2%). Combinations of different types of abnormalities were stated. Another 346 patients (22.1%) showed single cell aberrations; the significance of these is unclear at the moment. Constitutional chromosome aberrations were detected in 69 patients. The following chromosome aberrations were observed: 35 sex chromosomal aberrations (comprising hyperploidies of X or Y chromosomes, mosaicisms and derivative X and Y chromosomes), 34 autosomal aberrations including 14 reciprocal translocations, five Robertsonian translocations, six inversions, one marker chromosome, one trisomy 18 mosaicism and seven other structural aberrations. Three autosomal regions showed fragile sites: 6q13 in 2.9% of the patients, 17p12 and 10q24 in 0.05% each. In conclusion, our data show that a high number of infertile couples in an ICSI programme are affected by chromosome aberrations which occur in both sexes. It is suggested that a chromosomal analysis should be performed on both partners before ICSI treatment is initiated. (+info)Transmission of a Y chromosomal deletion involving the deleted in azoospermia (DAZ) and chromodomain (CDY1) genes from father to son through intracytoplasmic sperm injection: case report. (8/546)
The transmission of a deleted in azoospermia (DAZ) deletion from a severely oligozoospermic patient to his son following intracytoplasmic sperm injection (ICSI) treatment is reported. The case report highlights the fertilizing capacity of spermatozoa carrying Y chromosome deletions in patients treated with ICSI and stresses the importance of genetic counselling in severe male infertility. (+info)Sex chromosome aberrations refer to structural and numerical abnormalities in the sex chromosomes, which are typically represented as X and Y chromosomes in humans. These aberrations can result in variations in the number of sex chromosomes, such as Klinefelter syndrome (47,XXY), Turner syndrome (45,X), and Jacobs/XYY syndrome (47,XYY). They can also include structural changes, such as deletions, duplications, or translocations of sex chromosome material.
Sex chromosome aberrations may lead to a range of phenotypic effects, including differences in physical characteristics, cognitive development, fertility, and susceptibility to certain health conditions. The manifestation and severity of these impacts can vary widely depending on the specific type and extent of the aberration, as well as individual genetic factors and environmental influences.
It is important to note that while sex chromosome aberrations may pose challenges and require medical management, they do not inherently define or limit a person's potential, identity, or worth. Comprehensive care, support, and education can help individuals with sex chromosome aberrations lead fulfilling lives and reach their full potential.
Sex chromosomes, often denoted as X and Y, are one of the 23 pairs of human chromosomes found in each cell of the body. Normally, females have two X chromosomes (46,XX), and males have one X and one Y chromosome (46,XY). The sex chromosomes play a significant role in determining the sex of an individual. They contain genes that contribute to physical differences between men and women. Any variations or abnormalities in the number or structure of these chromosomes can lead to various genetic disorders and conditions related to sexual development and reproduction.
Chromosome aberrations refer to structural and numerical changes in the chromosomes that can occur spontaneously or as a result of exposure to mutagenic agents. These changes can affect the genetic material encoded in the chromosomes, leading to various consequences such as developmental abnormalities, cancer, or infertility.
Structural aberrations include deletions, duplications, inversions, translocations, and rings, which result from breaks and rearrangements of chromosome segments. Numerical aberrations involve changes in the number of chromosomes, such as aneuploidy (extra or missing chromosomes) or polyploidy (multiples of a complete set of chromosomes).
Chromosome aberrations can be detected and analyzed using various cytogenetic techniques, including karyotyping, fluorescence in situ hybridization (FISH), and comparative genomic hybridization (CGH). These methods allow for the identification and characterization of chromosomal changes at the molecular level, providing valuable information for genetic counseling, diagnosis, and research.
Chromosomes are thread-like structures that exist in the nucleus of cells, carrying genetic information in the form of genes. They are composed of DNA and proteins, and are typically present in pairs in the nucleus, with one set inherited from each parent. In humans, there are 23 pairs of chromosomes for a total of 46 chromosomes. Chromosomes come in different shapes and forms, including sex chromosomes (X and Y) that determine the biological sex of an individual. Changes or abnormalities in the number or structure of chromosomes can lead to genetic disorders and diseases.
Chromosome mapping, also known as physical mapping, is the process of determining the location and order of specific genes or genetic markers on a chromosome. This is typically done by using various laboratory techniques to identify landmarks along the chromosome, such as restriction enzyme cutting sites or patterns of DNA sequence repeats. The resulting map provides important information about the organization and structure of the genome, and can be used for a variety of purposes, including identifying the location of genes associated with genetic diseases, studying evolutionary relationships between organisms, and developing genetic markers for use in breeding or forensic applications.
The X chromosome is one of the two types of sex-determining chromosomes in humans (the other being the Y chromosome). It's one of the 23 pairs of chromosomes that make up a person's genetic material. Females typically have two copies of the X chromosome (XX), while males usually have one X and one Y chromosome (XY).
The X chromosome contains hundreds of genes that are responsible for the production of various proteins, many of which are essential for normal bodily functions. Some of the critical roles of the X chromosome include:
1. Sex Determination: The presence or absence of the Y chromosome determines whether an individual is male or female. If there is no Y chromosome, the individual will typically develop as a female.
2. Genetic Disorders: Since females have two copies of the X chromosome, they are less likely to be affected by X-linked genetic disorders than males. Males, having only one X chromosome, will express any recessive X-linked traits they inherit.
3. Dosage Compensation: To compensate for the difference in gene dosage between males and females, a process called X-inactivation occurs during female embryonic development. One of the two X chromosomes is randomly inactivated in each cell, resulting in a single functional copy per cell.
The X chromosome plays a crucial role in human genetics and development, contributing to various traits and characteristics, including sex determination and dosage compensation.
Karyotyping is a medical laboratory test used to study the chromosomes in a cell. It involves obtaining a sample of cells from a patient, usually from blood or bone marrow, and then staining the chromosomes so they can be easily seen under a microscope. The chromosomes are then arranged in pairs based on their size, shape, and other features to create a karyotype. This visual representation allows for the identification and analysis of any chromosomal abnormalities, such as extra or missing chromosomes, or structural changes like translocations or inversions. These abnormalities can provide important information about genetic disorders, diseases, and developmental problems.
In situ hybridization, fluorescence (FISH) is a type of molecular cytogenetic technique used to detect and localize the presence or absence of specific DNA sequences on chromosomes through the use of fluorescent probes. This technique allows for the direct visualization of genetic material at a cellular level, making it possible to identify chromosomal abnormalities such as deletions, duplications, translocations, and other rearrangements.
The process involves denaturing the DNA in the sample to separate the double-stranded molecules into single strands, then adding fluorescently labeled probes that are complementary to the target DNA sequence. The probe hybridizes to the complementary sequence in the sample, and the location of the probe is detected by fluorescence microscopy.
FISH has a wide range of applications in both clinical and research settings, including prenatal diagnosis, cancer diagnosis and monitoring, and the study of gene expression and regulation. It is a powerful tool for identifying genetic abnormalities and understanding their role in human disease.
Chromosome banding is a technique used in cytogenetics to identify and describe the physical structure and organization of chromosomes. This method involves staining the chromosomes with specific dyes that bind differently to the DNA and proteins in various regions of the chromosome, resulting in a distinct pattern of light and dark bands when viewed under a microscope.
The most commonly used banding techniques are G-banding (Giemsa banding) and R-banding (reverse banding). In G-banding, the chromosomes are stained with Giemsa dye, which preferentially binds to the AT-rich regions, creating a characteristic banding pattern. The bands are numbered from the centromere (the constriction point where the chromatids join) outwards, with the darker bands (rich in A-T base pairs and histone proteins) labeled as "q" arms and the lighter bands (rich in G-C base pairs and arginine-rich proteins) labeled as "p" arms.
R-banding, on the other hand, uses a different staining procedure that results in a reversed banding pattern compared to G-banding. The darker R-bands correspond to the lighter G-bands, and vice versa. This technique is particularly useful for identifying and analyzing specific regions of chromosomes that may be difficult to visualize with G-banding alone.
Chromosome banding plays a crucial role in diagnosing genetic disorders, identifying chromosomal abnormalities, and studying the structure and function of chromosomes in both clinical and research settings.
The Y chromosome is one of the two sex-determining chromosomes in humans and many other animals, along with the X chromosome. The Y chromosome contains the genetic information that helps to determine an individual's sex as male. It is significantly smaller than the X chromosome and contains fewer genes.
The Y chromosome is present in males, who inherit it from their father. Females, on the other hand, have two X chromosomes, one inherited from each parent. The Y chromosome includes a gene called SRY (sex-determining region Y), which initiates the development of male sexual characteristics during embryonic development.
It is worth noting that the Y chromosome has a relatively high rate of genetic mutation and degeneration compared to other chromosomes, leading to concerns about its long-term viability in human evolution. However, current evidence suggests that the Y chromosome has been stable for at least the past 25 million years.
Sister chromatid exchange (SCE) is a type of genetic recombination that takes place between two identical sister chromatids during the DNA repair process in meiosis or mitosis. It results in an exchange of genetic material between the two chromatids, creating a new combination of genes on each chromatid. This event is a normal part of cell division and helps to increase genetic variability within a population. However, an increased rate of SCEs can also be indicative of exposure to certain genotoxic agents or conditions that cause DNA damage.
Chromosomes are thread-like structures that contain genetic material, i.e., DNA and proteins, present in the nucleus of human cells. In humans, there are 23 pairs of chromosomes, for a total of 46 chromosomes, in each diploid cell. Twenty-two of these pairs are called autosomal chromosomes, which come in identical pairs and contain genes that determine various traits unrelated to sex.
The last pair is referred to as the sex chromosomes (X and Y), which determines a person's biological sex. Females have two X chromosomes (46, XX), while males possess one X and one Y chromosome (46, XY). Chromosomes vary in size, with the largest being chromosome 1 and the smallest being the Y chromosome.
Human chromosomes are typically visualized during mitosis or meiosis using staining techniques that highlight their banding patterns, allowing for identification of specific regions and genes. Chromosomal abnormalities can lead to various genetic disorders, including Down syndrome (trisomy 21), Turner syndrome (monosomy X), and Klinefelter syndrome (XXY).
Aneuploidy is a medical term that refers to an abnormal number of chromosomes in a cell. Chromosomes are thread-like structures located inside the nucleus of cells that contain genetic information in the form of genes.
In humans, the normal number of chromosomes in a cell is 46, arranged in 23 pairs. Aneuploidy occurs when there is an extra or missing chromosome in one or more of these pairs. For example, Down syndrome is a condition that results from an extra copy of chromosome 21, also known as trisomy 21.
Aneuploidy can arise during the formation of gametes (sperm or egg cells) due to errors in the process of cell division called meiosis. These errors can result in eggs or sperm with an abnormal number of chromosomes, which can then lead to aneuploidy in the resulting embryo.
Aneuploidy is a significant cause of birth defects and miscarriages. The severity of the condition depends on which chromosomes are affected and the extent of the abnormality. In some cases, aneuploidy may have no noticeable effects, while in others it can lead to serious health problems or developmental delays.
Chromosome disorders are a group of genetic conditions caused by abnormalities in the number or structure of chromosomes. Chromosomes are thread-like structures located in the nucleus of cells that contain most of the body's genetic material, which is composed of DNA and proteins. Normally, humans have 23 pairs of chromosomes, for a total of 46 chromosomes.
Chromosome disorders can result from changes in the number of chromosomes (aneuploidy) or structural abnormalities in one or more chromosomes. Some common examples of chromosome disorders include:
1. Down syndrome: a condition caused by an extra copy of chromosome 21, resulting in intellectual disability, developmental delays, and distinctive physical features.
2. Turner syndrome: a condition that affects only females and is caused by the absence of all or part of one X chromosome, resulting in short stature, lack of sexual development, and other symptoms.
3. Klinefelter syndrome: a condition that affects only males and is caused by an extra copy of the X chromosome, resulting in tall stature, infertility, and other symptoms.
4. Cri-du-chat syndrome: a condition caused by a deletion of part of the short arm of chromosome 5, resulting in intellectual disability, developmental delays, and a distinctive cat-like cry.
5. Fragile X syndrome: a condition caused by a mutation in the FMR1 gene on the X chromosome, resulting in intellectual disability, behavioral problems, and physical symptoms.
Chromosome disorders can be diagnosed through various genetic tests, such as karyotyping, chromosomal microarray analysis (CMA), or fluorescence in situ hybridization (FISH). Treatment for these conditions depends on the specific disorder and its associated symptoms and may include medical interventions, therapies, and educational support.
Sex chromosome disorders are genetic conditions that occur due to an atypical number or structure of the sex chromosomes, which are X and Y. Normally, females have two X chromosomes (XX), and males have one X and one Y chromosome (XY). However, in sex chromosome disorders, there is a variation in the number or composition of these chromosomes.
The most common sex chromosome disorders include:
1. Turner syndrome (Monosomy X): Occurs when a female has only one X chromosome (45,X). This condition affects about 1 in every 2,500 female births and can lead to short stature, infertility, heart defects, and learning disabilities.
2. Klinefelter syndrome (XXY): Occurs when a male has an extra X chromosome (47,XXY). This condition affects about 1 in every 500-1,000 male births and can lead to tall stature, infertility, breast development, and learning disabilities.
3. Jacobs syndrome (XYY): Occurs when a male has an extra Y chromosome (47,XYY). This condition affects about 1 in every 1,000 male births and can lead to tall stature, learning disabilities, and behavioral issues.
4. Triple X syndrome (XXX): Occurs when a female has an extra X chromosome (47,XXX). This condition affects about 1 in every 1,000 female births and can lead to mild developmental delays and learning disabilities.
5. Other rare sex chromosome disorders: These include conditions like 48,XXXX, 49,XXXXY, and mosaicism (a mixture of cells with different chromosome compositions).
Sex chromosome disorders can have varying degrees of impact on an individual's physical and cognitive development. While some individuals may experience significant challenges, others may have only mild or no symptoms at all. Early diagnosis and appropriate interventions can help improve outcomes for those affected by sex chromosome disorders.
Chromosome painting is a molecular cytogenetic technique used to identify and visualize the specific chromosomes or chromosomal regions that are present in an abnormal location or number in a cell. This technique uses fluorescent probes that bind specifically to different chromosomes or chromosomal regions, allowing for their identification under a fluorescence microscope.
The process of chromosome painting involves labeling different chromosomes or chromosomal regions with fluorescent dyes of distinct colors. The labeled probes are then hybridized to the metaphase chromosomes of a cell, and any excess probe is washed away. The resulting fluorescent pattern allows for the identification of specific chromosomes or chromosomal regions that have been gained, lost, or rearranged in the genome.
Chromosome painting has numerous applications in medical genetics, including prenatal diagnosis, cancer cytogenetics, and constitutional genetic disorders. It can help to identify chromosomal abnormalities such as translocations, deletions, and duplications that may contribute to disease or cancer development.
A chromosome is a thread-like structure that contains genetic material, made up of DNA and proteins, in the nucleus of a cell. In humans, there are 23 pairs of chromosomes, for a total of 46 chromosomes, in each cell of the body, with the exception of the sperm and egg cells which contain only 23 chromosomes.
The X chromosome is one of the two sex-determining chromosomes in humans. Females typically have two X chromosomes (XX), while males have one X and one Y chromosome (XY). The X chromosome contains hundreds of genes that are responsible for various functions in the body, including some related to sexual development and reproduction.
Humans inherit one X chromosome from their mother and either an X or a Y chromosome from their father. In females, one of the two X chromosomes is randomly inactivated during embryonic development, resulting in each cell having only one active X chromosome. This process, known as X-inactivation, helps to ensure that females have roughly equal levels of gene expression from the X chromosome, despite having two copies.
Abnormalities in the number or structure of the X chromosome can lead to various genetic disorders, such as Turner syndrome (X0), Klinefelter syndrome (XXY), and fragile X syndrome (an X-linked disorder caused by a mutation in the FMR1 gene).
Human chromosome pair 1 refers to the first pair of chromosomes in a set of 23 pairs found in the cells of the human body, excluding sex cells (sperm and eggs). Each cell in the human body, except for the gametes, contains 46 chromosomes arranged in 23 pairs. These chromosomes are rod-shaped structures that contain genetic information in the form of DNA.
Chromosome pair 1 is the largest pair, making up about 8% of the total DNA in a cell. Each chromosome in the pair consists of two arms - a shorter p arm and a longer q arm - connected at a centromere. Chromosome 1 carries an estimated 2,000-2,500 genes, which are segments of DNA that contain instructions for making proteins or regulating gene expression.
Defects or mutations in the genes located on chromosome 1 can lead to various genetic disorders and diseases, such as Charcot-Marie-Tooth disease type 1A, Huntington's disease, and certain types of cancer.
A micronucleus test is a type of genetic toxicology assay used to detect the presence of micronuclei in cells, which are small chromosomal fragments or whole chromosomes that have been missegregated during cell division. The test measures the frequency of micronuclei in cells exposed to a potential genotoxic agent, such as a chemical or radiation, and compares it to the frequency in untreated control cells.
The assay is typically performed on cultured mammalian cells, such as human lymphocytes or Chinese hamster ovary (CHO) cells, and involves exposing the cells to the test agent for a specific period of time, followed by staining and examination of the cells under a microscope. The micronuclei are identified based on their size, shape, and staining characteristics, and the frequency of micronucleated cells is calculated as a measure of genotoxic potential.
Micronucleus tests are widely used in regulatory toxicology to assess the genetic safety of chemicals, drugs, and other substances, and can provide valuable information on potential risks to human health. The test is also used in basic research to study the mechanisms of genotoxicity and chromosomal instability.
Human Y chromosomes are one of the two sex-determining chromosomes in humans (the other being the X chromosome). They are found in the 23rd pair of human chromosomes and are significantly smaller than the X chromosome.
The Y chromosome is passed down from father to son through the paternal line, and it plays a crucial role in male sex determination. The SRY gene (sex-determining region Y) on the Y chromosome initiates the development of male sexual characteristics during embryonic development.
In addition to the SRY gene, the human Y chromosome contains several other genes that are essential for sperm production and male fertility. However, the Y chromosome has a much lower gene density compared to other chromosomes, with only about 80 protein-coding genes, making it one of the most gene-poor chromosomes in the human genome.
Because of its small size and low gene density, the Y chromosome is particularly susceptible to genetic mutations and deletions, which can lead to various genetic disorders and male infertility. Nonetheless, the Y chromosome remains a critical component of human genetics and evolution, providing valuable insights into sex determination, inheritance patterns, and human diversity.
"Sex determination processes" refer to the series of genetic and biological events that occur during embryonic and fetal development which lead to the development of male or female physical characteristics. In humans, this process is typically determined by the presence or absence of a Y chromosome in the fertilized egg. If the egg has a Y chromosome, it will develop into a male (genetically XY) and if it does not have a Y chromosome, it will develop into a female (genetically XX).
The sex determination process involves the activation and repression of specific genes on the sex chromosomes, which direct the development of the gonads (ovaries or testes) and the production of hormones that influence the development of secondary sexual characteristics. This includes the development of internal and external genitalia, as well as other sex-specific physical traits.
It is important to note that while sex is typically determined by genetics and biology, gender identity is a separate construct that can be self-identified and may not align with an individual's biological sex.
Mutagenicity tests are a type of laboratory assays used to identify agents that can cause genetic mutations. These tests detect changes in the DNA of organisms, such as bacteria, yeast, or mammalian cells, after exposure to potential mutagens. The most commonly used mutagenicity test is the Ames test, which uses a strain of Salmonella bacteria that is sensitive to mutagens. If a chemical causes an increase in the number of revertants (reversion to the wild type) in the bacterial population, it is considered to be a mutagen. Other tests include the mouse lymphoma assay and the chromosomal aberration test. These tests are used to evaluate the potential genotoxicity of chemicals and are an important part of the safety evaluation process for new drugs, chemicals, and other substances.
Human chromosome pair 11 consists of two rod-shaped structures present in the nucleus of each cell in the human body. Each member of the pair is a single chromosome, and together they contain the genetic material that is inherited from both parents. They are located on the eleventh position in the standard karyotype, which is a visual representation of the 23 pairs of human chromosomes.
Chromosome 11 is one of the largest human chromosomes and contains an estimated 135 million base pairs. It contains approximately 1,400 genes that provide instructions for making proteins, as well as many non-coding RNA molecules that play a role in regulating gene expression.
Chromosome 11 is known to contain several important genes and genetic regions associated with various human diseases and conditions. For example, it contains the Wilms' tumor 1 (WT1) gene, which is associated with kidney cancer in children, and the neurofibromatosis type 1 (NF1) gene, which is associated with a genetic disorder that causes benign tumors to grow on nerves throughout the body. Additionally, chromosome 11 contains the region where the ABO blood group genes are located, which determine a person's blood type.
It's worth noting that human chromosomes come in pairs because they contain two copies of each gene, one inherited from the mother and one from the father. This redundancy allows for genetic diversity and provides a backup copy of essential genes, ensuring their proper function and maintaining the stability of the genome.
Chromosome pairing, also known as chromosome synapsis, is a process that occurs during meiosis, which is the type of cell division that results in the formation of sex cells or gametes (sperm and eggs).
In humans, each cell contains 23 pairs of chromosomes, for a total of 46 chromosomes. Of these, 22 pairs are called autosomal chromosomes, and they are similar in size and shape between the two copies in a pair. The last pair is called the sex chromosomes (X and Y), which determine the individual's biological sex.
During meiosis, homologous chromosomes (one from each parent) come together and pair up along their lengths in a process called synapsis. This pairing allows for the precise alignment of corresponding genes and genetic regions between the two homologous chromosomes. Once paired, the chromosomes exchange genetic material through a process called crossing over, which increases genetic diversity in the resulting gametes.
After crossing over, the homologous chromosomes separate during meiosis I, followed by the separation of sister chromatids (the two copies of each chromosome) during meiosis II. The end result is four haploid cells, each containing 23 chromosomes, which then develop into sperm or eggs.
Chromosome pairing is a crucial step in the process of sexual reproduction, ensuring that genetic information is accurately passed from one generation to the next while also promoting genetic diversity through recombination and independent assortment of chromosomes.
Cytogenetics is a branch of genetics that deals with the study of chromosomes and their structure, function, and abnormalities. It involves the examination of chromosome number and structure in the cells of an organism, usually through microscopic analysis of chromosomes prepared from cell cultures or tissue samples. Cytogenetic techniques can be used to identify chromosomal abnormalities associated with genetic disorders, cancer, and other diseases.
The process of cytogenetics typically involves staining the chromosomes to make them visible under a microscope, and then analyzing their number, size, shape, and banding pattern. Chromosomal abnormalities such as deletions, duplications, inversions, translocations, and aneuploidy (abnormal number of chromosomes) can be detected through cytogenetic analysis.
Cytogenetics is an important tool in medical genetics and has many clinical applications, including prenatal diagnosis, cancer diagnosis and monitoring, and identification of genetic disorders. Advances in molecular cytogenetic techniques, such as fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH), have improved the resolution and accuracy of chromosome analysis and expanded its clinical applications.
Human chromosome pair 7 consists of two rod-shaped structures present in the nucleus of each cell in the human body. Each member of the pair is a single chromosome, and together they contain the genetic material that is inherited from both parents. They are identical in size, shape, and banding pattern and are therefore referred to as homologous chromosomes.
Chromosome 7 is one of the autosomal chromosomes, meaning it is not a sex chromosome (X or Y). It is composed of double-stranded DNA that contains approximately 159 million base pairs and around 1,200 genes. Chromosome 7 contains several important genes associated with human health and disease, including those involved in the development of certain types of cancer, such as colon cancer and lung cancer, as well as genetic disorders such as Williams-Beuren syndrome and Charcot-Marie-Tooth disease.
Abnormalities in chromosome 7 have been linked to various genetic conditions, including deletions, duplications, translocations, and other structural changes. These abnormalities can lead to developmental delays, intellectual disabilities, physical abnormalities, and increased risk of certain types of cancer.
Chromosomes in plants are thread-like structures that contain genetic material, DNA, and proteins. They are present in the nucleus of every cell and are inherited from the parent plants during sexual reproduction. Chromosomes come in pairs, with each pair consisting of one chromosome from each parent.
In plants, like in other organisms, chromosomes play a crucial role in inheritance, development, and reproduction. They carry genetic information that determines various traits and characteristics of the plant, such as its physical appearance, growth patterns, and resistance to diseases.
Plant chromosomes are typically much larger than those found in animals, making them easier to study under a microscope. The number of chromosomes varies among different plant species, ranging from as few as 2 in some ferns to over 1000 in certain varieties of wheat.
During cell division, the chromosomes replicate and then separate into two identical sets, ensuring that each new cell receives a complete set of genetic information. This process is critical for the growth and development of the plant, as well as for the production of viable seeds and offspring.
Cytogenetic analysis is a laboratory technique used to identify and study the structure and function of chromosomes, which are the structures in the cell that contain genetic material. This type of analysis involves examining the number, size, shape, and banding pattern of chromosomes in cells, typically during metaphase when they are at their most condensed state.
There are several methods used for cytogenetic analysis, including karyotyping, fluorescence in situ hybridization (FISH), and comparative genomic hybridization (CGH). Karyotyping involves staining the chromosomes with a dye to visualize their banding patterns and then arranging them in pairs based on their size and shape. FISH uses fluorescent probes to label specific DNA sequences, allowing for the detection of genetic abnormalities such as deletions, duplications, or translocations. CGH compares the DNA content of two samples to identify differences in copy number, which can be used to detect chromosomal imbalances.
Cytogenetic analysis is an important tool in medical genetics and is used for a variety of purposes, including prenatal diagnosis, cancer diagnosis and monitoring, and the identification of genetic disorders.
Translocation, genetic, refers to a type of chromosomal abnormality in which a segment of a chromosome is transferred from one chromosome to another, resulting in an altered genome. This can occur between two non-homologous chromosomes (non-reciprocal translocation) or between two homologous chromosomes (reciprocal translocation). Genetic translocations can lead to various clinical consequences, depending on the genes involved and the location of the translocation. Some translocations may result in no apparent effects, while others can cause developmental abnormalities, cancer, or other genetic disorders. In some cases, translocations can also increase the risk of having offspring with genetic conditions.
"Silene" is a genus of flowering plants in the family Caryophyllaceae. It includes over 700 species that are found worldwide, particularly in temperate regions. These plants are commonly known as catchflies or campions. They are usually herbaceous and can vary in size from small annuals to large perennials. The flowers of Silene species are typically radial symmetrical with five distinct petals, often with notched or lobed ends. Some species have inflated calyxes that enclose the flower buds, giving them a bladder-like appearance.
However, it's important to note that "Silene" is not a medical term and does not have a direct application in human health or medicine.
A chromosome deletion is a type of genetic abnormality that occurs when a portion of a chromosome is missing or deleted. Chromosomes are thread-like structures located in the nucleus of cells that contain our genetic material, which is organized into genes.
Chromosome deletions can occur spontaneously during the formation of reproductive cells (eggs or sperm) or can be inherited from a parent. They can affect any chromosome and can vary in size, from a small segment to a large portion of the chromosome.
The severity of the symptoms associated with a chromosome deletion depends on the size and location of the deleted segment. In some cases, the deletion may be so small that it does not cause any noticeable symptoms. However, larger deletions can lead to developmental delays, intellectual disabilities, physical abnormalities, and various medical conditions.
Chromosome deletions are typically detected through a genetic test called karyotyping, which involves analyzing the number and structure of an individual's chromosomes. Other more precise tests, such as fluorescence in situ hybridization (FISH) or chromosomal microarray analysis (CMA), may also be used to confirm the diagnosis and identify the specific location and size of the deletion.
Human chromosome pair 13 consists of two rod-shaped structures present in the nucleus of each cell in the human body. Each chromosome is made up of DNA tightly coiled around histone proteins, forming a complex structure called a chromatin.
Chromosomes carry genetic information in the form of genes, which are sequences of DNA that code for specific traits and functions. Human cells typically have 23 pairs of chromosomes, for a total of 46 chromosomes. Chromosome pair 13 is one of the autosomal pairs, meaning it is not a sex chromosome (X or Y).
Chromosome pair 13 contains several important genes that are associated with various genetic disorders, such as cri-du-chat syndrome and Phelan-McDermid syndrome. Cri-du-chat syndrome is caused by a deletion of the short arm of chromosome 13 (13p), resulting in distinctive cat-like crying sounds in infants, developmental delays, and intellectual disabilities. Phelan-McDermid syndrome is caused by a deletion or mutation of the terminal end of the long arm of chromosome 13 (13q), leading to developmental delays, intellectual disability, absent or delayed speech, and autistic behaviors.
It's important to note that while some genetic disorders are associated with specific chromosomal abnormalities, many factors can contribute to the development and expression of these conditions, including environmental influences and interactions between multiple genes.
Mutagens are physical or chemical agents that can cause permanent changes in the structure of genetic material, including DNA and chromosomes, leading to mutations. These mutations can be passed down to future generations and may increase the risk of cancer and other diseases. Examples of mutagens include ultraviolet (UV) radiation, tobacco smoke, and certain chemicals found in industrial settings. It is important to note that not all mutations are harmful, but some can have negative effects on health and development.
X chromosome inactivation (XCI) is a process that occurs in females of mammalian species, including humans, to compensate for the difference in gene dosage between the sexes. Females have two X chromosomes, while males have one X and one Y chromosome. To prevent females from having twice as many X-linked genes expressed as males, one of the two X chromosomes in each female cell is randomly inactivated during early embryonic development.
XCI results in the formation of a condensed and transcriptionally inactive structure called a Barr body, which can be observed in the nucleus of female cells. This process ensures that females express similar levels of X-linked genes as males, maintaining a balanced gene dosage. The choice of which X chromosome is inactivated (maternal or paternal) is random and occurs independently in each cell, leading to a mosaic expression pattern of X-linked genes in different cells and tissues of the female body.
Chromosome segregation is the process that occurs during cell division (mitosis or meiosis) where replicated chromosomes are separated and distributed equally into two daughter cells. Each chromosome consists of two sister chromatids, which are identical copies of genetic material. During chromosome segregation, these sister chromatids are pulled apart by a structure called the mitotic spindle and moved to opposite poles of the cell. This ensures that each new cell receives one copy of each chromosome, preserving the correct number and composition of chromosomes in the organism.
Nuclear warfare is not a medical term per se, but it refers to a military conflict using nuclear weapons. However, the medical and public health communities have studied the potential consequences of nuclear warfare extensively due to its catastrophic health impacts.
In a medical context, a nuclear explosion releases a massive amount of energy in the form of light, heat, and a shockwave, which can cause significant destruction and loss of life from the blast alone. Additionally, the explosion produces radioactive materials that contaminate the environment, leading to both immediate and long-term health effects.
Immediate medical consequences of nuclear warfare include:
1. Blast injuries: The shockwave from a nuclear explosion can cause severe trauma, including fractures, internal injuries, and burns.
2. Radiation exposure: Acute radiation sickness can occur in individuals exposed to high levels of ionizing radiation, leading to symptoms such as nausea, vomiting, diarrhea, fever, and potentially death.
3. Thermal burns: The intense heat generated by a nuclear explosion can cause severe thermal burns, similar to those seen in major fires or explosions.
4. Eye injuries: Flash blindness and retinal burns can occur due to the bright flash of light emitted during the explosion.
Long-term medical consequences of nuclear warfare include:
1. Radiation-induced cancers: Exposure to ionizing radiation increases the risk of developing various types of cancer, such as leukemia and solid tumors, over time.
2. Genetic mutations: Ionizing radiation can cause genetic mutations that may be passed down through generations, potentially leading to birth defects and other health issues.
3. Psychological trauma: The aftermath of a nuclear war would likely result in significant psychological distress, including post-traumatic stress disorder (PTSD), depression, and anxiety.
4. Environmental contamination: Radioactive fallout from a nuclear explosion can contaminate the environment, making large areas uninhabitable for extended periods. This contamination could lead to food and water shortages, further exacerbating health issues.
Preparing for and responding to a nuclear warfare event would require a coordinated effort between medical professionals, emergency responders, and public health officials to minimize the immediate and long-term health impacts on affected populations.
Corneal wavefront aberration is a measurement of the irregularities in the shape and curvature of the cornea, which can affect the way light enters the eye and is focused on the retina. A wavefront aberration test uses a device to measure the refraction of light as it passes through the cornea and calculates the degree of any distortions or irregularities in the wavefront of the light. This information can be used to guide treatment decisions, such as the prescription for eyeglasses or contact lenses, or the planning of a surgical procedure to correct the aberration.
Corneal wavefront aberrations can be classified into two types: low-order and high-order aberrations. Low-order aberrations include myopia (nearsightedness), hyperopia (farsightedness), and astigmatism, which are common refractive errors that can be easily corrected with glasses or contact lenses. High-order aberrations are more complex irregularities in the wavefront of light that cannot be fully corrected with traditional eyeglasses or contact lenses. These may include coma, trefoil, and spherical aberration, among others.
High-order corneal wavefront aberrations can affect visual quality, causing symptoms such as glare, halos around lights, and decreased contrast sensitivity. They are often associated with conditions that cause changes in the shape of the cornea, such as keratoconus or corneal surgery. In some cases, high-order aberrations can be corrected with specialized contact lenses or refractive surgery procedures such as wavefront-guided LASIK or PRK.
Y-linked genes are a type of sex-limited gene that is located on the Y chromosome. These genes are only present in males because they are passed from father to son through the paternal Y chromosome during reproduction. They are not paired with any corresponding genes on the X chromosome, and therefore, they do not have a counterpart to complement their function.
Y-linked genes play an essential role in sex determination and male development. For example, the SRY gene, which is located on the Y chromosome, encodes a protein that triggers testis development during embryonic development. Other Y-linked genes are involved in spermatogenesis, the process of producing sperm cells.
Since Y-linked genes are not present in females, they do not have any direct impact on female traits or characteristics. However, mutations in Y-linked genes can cause various genetic disorders that affect male fertility and development, such as Klinefelter syndrome, XYY syndrome, and other sex chromosome aneuploidies.
Human chromosome pair 18 consists of two rod-shaped structures present in the nucleus of each cell of the human body. Chromosomes are made up of DNA, protein, and RNA, and they carry genetic information that determines an individual's physical characteristics, biochemical processes, and susceptibility to disease.
Chromosome pair 18 is one of the 23 pairs of chromosomes that make up the human genome. Each member of chromosome pair 18 has a length of about 75 million base pairs and contains around 600 genes. Chromosome pair 18 is also known as the "smart chromosome" because it contains many genes involved in brain development, function, and cognition.
Abnormalities in chromosome pair 18 can lead to genetic disorders such as Edwards syndrome (trisomy 18), in which there is an extra copy of chromosome 18, or deletion of a portion of the chromosome, leading to various developmental and cognitive impairments.
Americium (Am-241) is a radioactive metallic element with the symbol "Am" and atomic number 95. It is a member of the actinide series and does not occur naturally, but can be produced in nuclear reactors. Americium-241 is most commonly used as a source of ionizing radiation in smoke detectors.
It is important to note that handling and storing americium requires proper training and equipment due to its radioactive nature. Improper handling or disposal can result in serious health risks, including radiation exposure and contamination.
Lymphocytes are a type of white blood cell that is an essential part of the immune system. They are responsible for recognizing and responding to potentially harmful substances such as viruses, bacteria, and other foreign invaders. There are two main types of lymphocytes: B-lymphocytes (B-cells) and T-lymphocytes (T-cells).
B-lymphocytes produce antibodies, which are proteins that help to neutralize or destroy foreign substances. When a B-cell encounters a foreign substance, it becomes activated and begins to divide and differentiate into plasma cells, which produce and secrete large amounts of antibodies. These antibodies bind to the foreign substance, marking it for destruction by other immune cells.
T-lymphocytes, on the other hand, are involved in cell-mediated immunity. They directly attack and destroy infected cells or cancerous cells. T-cells can also help to regulate the immune response by producing chemical signals that activate or inhibit other immune cells.
Lymphocytes are produced in the bone marrow and mature in either the bone marrow (B-cells) or the thymus gland (T-cells). They circulate throughout the body in the blood and lymphatic system, where they can be found in high concentrations in lymph nodes, the spleen, and other lymphoid organs.
Abnormalities in the number or function of lymphocytes can lead to a variety of immune-related disorders, including immunodeficiency diseases, autoimmune disorders, and cancer.
Mosaicism, in the context of genetics and medicine, refers to the presence of two or more cell lines with different genetic compositions in an individual who has developed from a single fertilized egg. This means that some cells have one genetic makeup, while others have a different genetic makeup. This condition can occur due to various reasons such as errors during cell division after fertilization.
Mosaicism can involve chromosomes (where whole or parts of chromosomes are present in some cells but not in others) or it can involve single genes (where a particular gene is present in one form in some cells and a different form in others). The symptoms and severity of mosaicism can vary widely, depending on the type and location of the genetic difference and the proportion of cells that are affected. Some individuals with mosaicism may not experience any noticeable effects, while others may have significant health problems.
Artificial bacterial chromosomes (ABCs) are synthetic replicons that are designed to function like natural bacterial chromosomes. They are created through the use of molecular biology techniques, such as recombination and cloning, to construct large DNA molecules that can stably replicate and segregate within a host bacterium.
ABCs are typically much larger than traditional plasmids, which are smaller circular DNA molecules that can also replicate in bacteria but have a limited capacity for carrying genetic information. ABCs can accommodate large DNA inserts, making them useful tools for cloning and studying large genes, gene clusters, or even entire genomes of other organisms.
There are several types of ABCs, including bacterial artificial chromosomes (BACs), P1-derived artificial chromosomes (PACs), and yeast artificial chromosomes (YACs). BACs are the most commonly used type of ABC and can accommodate inserts up to 300 kilobases (kb) in size. They have been widely used in genome sequencing projects, functional genomics studies, and protein production.
Overall, artificial bacterial chromosomes provide a powerful tool for manipulating and studying large DNA molecules in a controlled and stable manner within bacterial hosts.
Human chromosome pair 21 consists of two rod-shaped structures present in the nucleus of each cell in the human body. Each member of the pair is a single chromosome, and they are identical to each other. Chromosomes are made up of DNA, which contains genetic information that determines many of an individual's traits and characteristics.
Chromosome pair 21 is one of the 23 pairs of human autosomal chromosomes, meaning they are not sex chromosomes (X or Y). Chromosome pair 21 is the smallest of the human chromosomes, and it contains approximately 48 million base pairs of DNA. It contains around 200-300 genes that provide instructions for making proteins and regulating various cellular processes.
Down syndrome, a genetic disorder characterized by intellectual disability, developmental delays, distinct facial features, and sometimes heart defects, is caused by an extra copy of chromosome pair 21 or a part of it. This additional genetic material can lead to abnormalities in brain development and function, resulting in the characteristic symptoms of Down syndrome.
X-linked genes are those genes that are located on the X chromosome. In humans, females have two copies of the X chromosome (XX), while males have one X and one Y chromosome (XY). This means that males have only one copy of each X-linked gene, whereas females have two copies.
X-linked genes are important in medical genetics because they can cause different patterns of inheritance and disease expression between males and females. For example, if a mutation occurs in an X-linked gene, it is more likely to affect males than females because males only have one copy of the gene. This means that even a single mutated copy of the gene can cause the disease in males, while females may be carriers of the mutation and not show any symptoms due to their second normal copy of the gene.
X-linked recessive disorders are more common in males than females because they only have one X chromosome. Examples of X-linked recessive disorders include Duchenne muscular dystrophy, hemophilia, and color blindness. In contrast, X-linked dominant disorders can affect both males and females, but females may have milder symptoms due to their second normal copy of the gene. Examples of X-linked dominant disorders include Rett syndrome and incontinentia pigmenti.
Human chromosome pair 17 consists of two rod-shaped structures present in the nucleus of each human cell. Each chromosome is made up of DNA tightly coiled around histone proteins, forming a complex called chromatin. Chromosomes carry genetic information in the form of genes, which are segments of DNA that contain instructions for the development and function of an organism.
Human cells typically have 23 pairs of chromosomes, for a total of 46 chromosomes. Pair 17 is one of the autosomal pairs, meaning it is not a sex chromosome (X or Y). Chromosome 17 is a medium-sized chromosome and contains an estimated 800 million base pairs of DNA. It contains approximately 1,500 genes that provide instructions for making proteins and regulating various cellular processes.
Chromosome 17 is associated with several genetic disorders, including inherited cancer syndromes such as Li-Fraumeni syndrome and hereditary nonpolyposis colorectal cancer (HNPCC). Mutations in genes located on chromosome 17 can increase the risk of developing various types of cancer, including breast, ovarian, colon, and pancreatic cancer.
Metaphase is a phase in the cell division process (mitosis or meiosis) where the chromosomes align in the middle of the cell, also known as the metaphase plate or equatorial plane. During this stage, each chromosome consists of two sister chromatids attached to each other by a protein complex called the centromere. The spindle fibers from opposite poles of the cell attach to the centromeres of each chromosome, and through a process called congression, they align the chromosomes in the middle of the cell. This alignment allows for accurate segregation of genetic material during the subsequent anaphase stage.
Chromosome breakage is a medical term that refers to the breaking or fragmentation of chromosomes, which are thread-like structures located in the nucleus of cells that carry genetic information. Normally, chromosomes are tightly coiled and consist of two strands called chromatids, joined together at a central point called the centromere.
Chromosome breakage can occur spontaneously or be caused by environmental factors such as radiation or chemicals, or inherited genetic disorders. When a chromosome breaks, it can result in various genetic abnormalities, depending on the location and severity of the break.
For instance, if the break occurs in a region containing important genes, it can lead to the loss or alteration of those genes, causing genetic diseases or birth defects. In some cases, the broken ends of the chromosome may rejoin incorrectly, leading to chromosomal rearrangements such as translocations, deletions, or inversions. These rearrangements can also result in genetic disorders or cancer.
Chromosome breakage is commonly observed in individuals with certain inherited genetic conditions, such as Bloom syndrome, Fanconi anemia, and ataxia-telangiectasia, which are characterized by an increased susceptibility to chromosome breakage due to defects in DNA repair mechanisms.
Bacterial chromosomes are typically circular, double-stranded DNA molecules that contain the genetic material of bacteria. Unlike eukaryotic cells, which have their DNA housed within a nucleus, bacterial chromosomes are located in the cytoplasm of the cell, often associated with the bacterial nucleoid.
Bacterial chromosomes can vary in size and structure among different species, but they typically contain all of the genetic information necessary for the survival and reproduction of the organism. They may also contain plasmids, which are smaller circular DNA molecules that can carry additional genes and can be transferred between bacteria through a process called conjugation.
One important feature of bacterial chromosomes is their ability to replicate rapidly, allowing bacteria to divide quickly and reproduce in large numbers. The replication of the bacterial chromosome begins at a specific origin point and proceeds in opposite directions until the entire chromosome has been copied. This process is tightly regulated and coordinated with cell division to ensure that each daughter cell receives a complete copy of the genetic material.
Overall, the study of bacterial chromosomes is an important area of research in microbiology, as understanding their structure and function can provide insights into bacterial genetics, evolution, and pathogenesis.
Karyotype
List of MeSH codes (C23)
List of MeSH codes (G13)
Micronucleus
Chromosome abnormality
Theodoxus fluviatilis
Autosome
Mutagen
XX gonadal dysgenesis
Vole
Chromosome
List of organisms by chromosome count
Chromosomal translocation
Campomelic dysplasia
Cri du chat syndrome
Preimplantation genetic diagnosis
Isochromosome
Cytogenetics
Virtual karyotype
Achromatopsia
X-chromosome reactivation
Selfish genetic element
Epithelioid sarcoma
Malgorzata Lamacz
Radiation Effects Research Foundation
Polysomy
Genetics and abortion
Spermatozoon
Henry Heng
HeLa
Loricariidae
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A gene from the human sex-determining region encodes a protein with homology to a conserved DNA-binding motif
Karyotype - Wikipedia
Klinefelter Syndrome: Practice Essentials, Pathophysiology, Epidemiology
P Medical Conditions, Illnesses & Diseases | ClusterMed.info
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Aneuploidy6
- XXY aneuploidy, the most common human sex chromosome disorder, has a prevalence of 1 in 500 males. (medscape.com)
- Conclusion: We observed high frequency of aneuploidy and sex chromosomal mosaicism in azoospermic men and high structural aberrations in males with low sperm quality. (ijfs.ir)
- So that, high chromosomal aneuploidy was detected in males with lower sperm count and high structural aberration was detected in males with low sperm quality. (ijfs.ir)
- Aneuploidy is a condition in which there is the addition or deletion of one or more chromosomes in a diploid set of chromosomes. (biologyideas.com)
- Aneuploidy may be hypoploidy (loss of one chromosome from a genome) or hyperdiploid (one or more chromosomes extra in a set of chromosomes). (biologyideas.com)
- Aneuploidy - failure of segregation of chromatids during cell division cycle results in the gain or loss of chromosome. (solarpoultry.com)
Abnormalities12
- Karyotyping is the process by which a karyotype is discerned by determining the chromosome complement of an individual, including the number of chromosomes and any abnormalities. (wikipedia.org)
- The addition of more than one extra X or Y chromosome to a normal male karyotype results in variable cognitive and physical abnormalities. (medscape.com)
- Secondary chromosome abnormalities were found in 62% of the cases, most often loss of a sex chromosome. (lu.se)
- Trisomy of sex chromosomes is compatible with life, but will cause phenotypic abnormalities. (mindmeister.com)
- The genetic controversy about LSD started in 1967 when Cohen, Marinello and Back (22) published a paper suggesting that LSD should be added to the list of substances capable of causing abnormalities in the chromosomes. (druglibrary.net)
- In general, the extent of phenotypic abnormalities, including mental retardation, is directly related to the number of supernumerary X chromosomes. (medscape.com)
- Well-known examples are some chromosomal translocations or sex-chromosomal abnormalities and Y-chromosome deletions. (virascience.com)
- Of those, 116 (13.2%) had sex chromosome abnormalities and 20(2.3%) had autosomal chromosome abnormalities. (ijfs.ir)
- Chromosomal abnormalities are changes to the number or structure of chromosomes that can lead to birth defects or other health disorders. (solarpoultry.com)
- Other evidence of chromosomal abnormalities include abnormal sexual development, behavioral disturbances, malignancy (e.g., the Philadelphia chromosome in chronic myelocytic leukemia), and spontaneous abortion. (solarpoultry.com)
- Knowledge on the prevalence of sex chromosome abnormalities (SCAs) is limited, and delayed diagnosis or non-diagnosis of SCAs are a continuous concern. (biomedcentral.com)
- It has been shown that germ cells with an extra Y chromosome from men with the 47 XYY karyotype have abnormal meiotic pairing suggesting disrupted meiosis eventual sperm apoptosis and subsequent oligozoospermia and infertility [15 16 Structural chromosomal abnormalities (SCAs) include deletions duplications translocations (balanced imbalanced and Robertsonian) and inversions. (biobender.com)
Genetic19
- These differences could have resulted from successive unequal translocations which removed all the essential genetic material from a chromosome, permitting its loss without penalty to the organism (the dislocation hypothesis) or through fusion. (wikipedia.org)
- A number of scientific papers have been published indicating that LSD might cause structural changes in the chromosomes, genetic mutations, disturbances of embryonic development, and malignant degeneration of cells. (druglibrary.net)
- In eukaryotes the genetic material is organized as distinct structural entities called chromosomes. (oracleias.org)
- Eukaryotic chromosome contain many origin of replications and the genetic material will only replicate at the S phase of cell cycle. (oracleias.org)
- For the genetic algorithm, see Chromosome (genetic algorithm) . (wikipedia.org)
- A chromosome is a long DNA molecule with part or all of the genetic material of an organism. (wikipedia.org)
- Wilhelm Roux suggested that each chromosome carries a different genetic configuration , and Boveri was able to test and confirm this hypothesis. (wikipedia.org)
- Second, contribution of genetic aberrations to the clinical outcome was assessed and an aberration-specific score was assigned to each prognostically relevant alteration. (bvsalud.org)
- Genetic analysis has pinpointed 3 regions of Yq chromosome that are microdeletion hotspots. (cloudhealthlabs.com)
- Variability of phenotype depends on the percentage of monosomic cells in different tissues and on the genetic material deleted during the formation of ring Y chromosome. (juniperpublishers.com)
- Inversions: A portion of the chromosome has broken off, turned upside down, and reattached, therefore the genetic material is inverted. (solarpoultry.com)
- Genetic Disorders refer to any abnormality in the individual gene(s) or the chromosomes which are caused due to the change in the sequence of the DNA or gain or loss of gene(s) or chromosomes. (solarpoultry.com)
- Morgan, Sturtevant, Bridges and Muller constructed the first genetic linkage maps from recombination studies in crosses made in the fruit fly and from cytological preparations of its polytene salivary gland chromosomes [ 4 - 6 ]. (biomedcentral.com)
- In 1944 it was realized that genetic transformation in bacteria was due to DNA and not protein and that DNA was the molecule responsible for heredity in genes and chromosomes [ 8 ]. (biomedcentral.com)
- Since the genetic code was deciphered much has been learnt about the chromosome structure shared by all organisms from yeast to human. (biomedcentral.com)
- AVL-292 All genetic defects AVL-292 can be divided into the following categories: chromosome aberrations DNA copy number variants (micro deletions and duplications) single-gene disorders complex conditions and epigenetic disorders. (biobender.com)
- OBJECTIVE@#To explore the genetic basis of three children with disorders of sex development (DSD) in association with rare Y chromosome rearrangements. (bvsalud.org)
- CONCLUSION@#Combined use of genetic techniques can delineate complex rearrangements involving Y chromosome in patients featuring short stature and DSD. (bvsalud.org)
- Several esoteric (but quintessentially fly) genetic subjects are also given an unusually full treatment here, including autosynaptic chromosomes, transvection and position effect. (silverchair.com)
Karyotype12
- A karyotype is the general appearance of the complete set of chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. (wikipedia.org)
- A karyogram or idiogram is a graphical depiction of a karyotype, wherein chromosomes are generally organized in pairs, ordered by size and position of centromere for chromosomes of the same size. (wikipedia.org)
- A full account of a karyotype may therefore include the number, type, shape and banding of the chromosomes, as well as other cytogenetic information. (wikipedia.org)
- [ 1 ] The etiology was thought to be due to an endocrine disorder of unknown cause, until 1959, when Jacobs et al recognized that Klinefelter syndrome was a chromosomal disorder in which there is an extra X chromosome, resulting in the karyotype 47,XXY. (medscape.com)
- Today, the term Klinefelter syndrome (KS) refers to a group of chromosomal disorders in which the normal male karyotype, 46,XY, has at least one extra X chromosome. (medscape.com)
- Exclusion criteria comprised constitutional hypodiploidy, monosomy 7, composite karyotype, and t(8;21) with concurring sex chromosome loss. (bvsalud.org)
- It is defined classically by a 47,XXY karyotype with variants that demonstrate additional X and Y chromosomes. (medscape.com)
- A post-natal karyotype and chromosomal SNP microarray revealed deletions of both terminal regions of the Y chromosome, consistent with the prenatal diagnosis of the ring Y chromosome. (juniperpublishers.com)
- On karyotype, the presumptive ring Y chromosome was present in 29% of the cells and a single X chromosome was present in the other 71% of cells. (juniperpublishers.com)
- i.e. azoospermia and oligozoospermia [6 11 12 15 The aberrations include numerical defects such as the XYY karyotype in Klinefelter syndrome or its variants and structural rearrangements Robertsonian translocations balanced reciprocal AVL-292 translocations and inversions. (biobender.com)
- Rarely infertile men with normal karyotype have chromosome aberrations in sperm [16]. (biobender.com)
- Increased germ cell defects have been reported for chromosomes 21 22 X and Y [15 16 Klinefelter syndrome (KS karyotype 47 XXY) is the most common chromosomal aberration detected in up to 14% of infertile patients with azoospermia [17]. (biobender.com)
Abnormal4
- Abnormal number or structure of the SEX CHROMOSOMES. (clustermed.info)
- Whether the morbidity associated with Klinefelter syndrome is a result of hypogonadism and hyperestrogenism or due to abnormal function of X chromosome linked genes is unclear. (medscape.com)
- The result is an abnormal number of chromosomes. (solarpoultry.com)
- chromosomal disorders It is caused due to absence or excess or abnormal arrangement of one or more chromosomes. (solarpoultry.com)
Pair of sex chromosomes1
- Human cells have 23 pairs of chromosomes(22 pairs of autosomes and 1 pair of sex chromosomes)giving total of 46 per cell. (oracleias.org)
Loss of a sex chromosome2
- On the contrary, although loss of a sex chromosome is observed in a broad range of hematological malignancies, how it cooperates in disease development is less understood. (oncotarget.com)
- With the widespread detection of loss of a sex chromosome in different hematological malignances, the elucidation of the role of pseudoautosomal region genes in the development and progression of these diseases would be invaluable to the field. (oncotarget.com)
Autosomal chromosomes2
- So, in normal diploid organisms, autosomal chromosomes are present in two copies. (wikipedia.org)
- Primary amenorrhea which result commonly from sex chromosome aberration as geneticabnormalities, may result from oneaberration in autosomal chromosomes or in association with sex chromosomal aberrations. (iasj.net)
Aneuploidies3
- Other sex chromosomal aneuploidies are included in the KS group of chromosomal disorders. (medscape.com)
- The most common chromosomal aberrations associated especially with severe oligo- and azoospermia are sex chromosome aneuploidies and chromosomal translocations. (virascience.com)
- Although the sperm of Klinefelter men usually have a normal 23 X or 23 Y haploid genome an increased rate of autosomal and sex chromosome aneuploidies was reported in KS men's offspring [19]. (biobender.com)
Autosomes3
- A ring chromosome is an extremely rare chromosomal aberration, which can occur in autosomes and sex chromosomes. (juniperpublishers.com)
- The mother and father each contribute one set of 22 autosomes and one sex chromosome. (solarpoultry.com)
- Presentation Summary : Human Chromosomal Disorders Human disorders due to chromosome alterations in autosomes (Chromosomes 1-22). (solarpoultry.com)
Genetics1
- A gene is a segment of deoxyribonucleic acid (DNA) and contains the code for a specific protein that functions in one or more types of cells in the body (see Genes and Chromosomes for a discussion about genetics). (solarpoultry.com)
Meiosis4
- The failure of homologous CHROMOSOMES or CHROMATIDS to segregate during MITOSIS or MEIOSIS with the result that one daughter cell has both of a pair of parental chromosomes or chromatids and the other has none. (nih.gov)
- Cyril Darlington pioneered plant cytogenetics in 1920-30 and made important advances in our understanding of mechanisms of chiasma formation and the behavior of sex chromosomes in meiosis [ 7 ]. (biomedcentral.com)
- Usually the extra X is result of chromosome nondisjunction in male or female meiosis [18]. (biobender.com)
- Golic and Hawley are progeny of the Larry Sandler lineage, steeped in the traditions of meiosis, hard-core chromosome mechanics, fly lore and scholarship. (silverchair.com)
Centromere6
- Structures like centromere, kinetochore, secondary constriction and chromosomal arms are not formed in prokaryotic chromosomes. (oracleias.org)
- Eukaryotic chromosome contains centromere kinetochore and chromosomal arms. (oracleias.org)
- [4] Before this happens, each chromosome is duplicated ( S phase ), and both copies are joined by a centromere , resulting either in an X-shaped structure (pictured above), if the centromere is located equatorially, or a two-arm structure, if the centromere is located distally. (wikipedia.org)
- Iso-chromosomes: A new type of chromo-some may arise from a break (i.e., a misdivision) at the centromere. (solarpoultry.com)
- of someones chromosomes (while a cell is in mitosis), cut them out and match them up using size, banding pattern and centromere position as guides. (solarpoultry.com)
- We now recognize that, following DNA replication, the metaphase chromosome consists of two chromatids held together by a centromere and by cohesin. (biomedcentral.com)
Deletions2
- With this test the most common causes of male infertility can be detected: AZF deletions on the Y-chromosome, (non-mosaic) sex chromosomal aberrations (e.g. (radboudumc.nl)
- Like deletions, duplications can happen anywhere along the chromosome. (solarpoultry.com)
Somatic4
- The basic number of chromosomes in the somatic cells of an individual or a species is called the somatic number and is designated 2n. (wikipedia.org)
- As the number of supernumerary X chromosomes increases, somatic and cognitive development are more likely to be affected. (medscape.com)
- The review provides a brief account of the structure of somatic and meiotic chromosomes, stressing the high conservation of structure in plants and animals, with emphasis on aspects that require further research. (biomedcentral.com)
- These studies reaffirmed that chromosome structure and behavior in somatic and germ cell divisions were common to all plants and animals. (biomedcentral.com)
Klinefelter1
- In 1959, these men with Klinefelter syndrome were discovered to have an extra X chromosome (genotype XXY) instead of the usual male sex complement (genotype XY). (medscape.com)
Cytogenetics2
- The future of molecular cytogenetics is likely to depend on a better knowledge of chromosome structure and function. (biomedcentral.com)
- One of the purposes of this review is to encourage research into chromosome structure as this could help advance molecular cytogenetics. (biomedcentral.com)
Abnormality2
- Mutagenic studies consisted of unscheduled DNA synthesis in human diploid WI-38 cells, mutation frequency in host mediated assays, sex linked recessive lethal mutation and loss of X or Y chromosomes in Drosophila melanogaster, spermhead abnormality in rats and mice, chromosomal aberrations in rat bone marrow, and rat dominant lethal experiments. (cdc.gov)
- Perchloroethylene caused spermhead abnormality in mice, positive responses in host mediated assay, and weak or borderline responses in tests for unscheduled DNA synthesis and bone marrow aberrations. (cdc.gov)
Homologous2
- Although the X and Y sex chromosomes are highly divergent, the pseudoautosomal regions are homologous between both chromosomes. (oncotarget.com)
- In this condition, there is one chromosome less in one homologous pair i.e. 2n - 1 condition. (biologyideas.com)
Complete set of chromosomes1
- The ploidy can occur either in the complete set of chromosomes or in the individual chromosomes. (biologyideas.com)
Cytogenetic3
- The sensitivity, accuracy and feasibility of application of SCE as an in vitro screening test has been evaluated against cytogenetic aberrations and the Ames test. (soton.ac.uk)
- A method is proposed to allow quantitative estimates to be made of mutation frequency.The induction of SCE and cytogenetic aberrations in human lymphocytes and point-mutation in Salmonella has been investigated following exposure to a range of selected direct-acting chemical mutagens. (soton.ac.uk)
- Standard chromosome analysis by G-banding has a limited resolution, but molecular cytogenetic techniques, such as multi-subtelomeric FISH, microdeletion FISH, multicolour FISH and comparative genomic hybridisation (CGH), have played an important role for the diagnosis of MR during the past decade. (bmj.com)
Structural3
- 22) * After my arrival in the United States, I participated in a major study concentrating on structural changes of the chromosomes in the white blood cells following LSD administration. (druglibrary.net)
- The first group includes papers describing structural changes of the chromosomes produced by LSD in vitro , ** in these experiments various concentrations of LSD are added to cultures of cells from human, animal, or plant tissues in a test-tube. (druglibrary.net)
- The possibility of inducing structural changes in the chromosomes by exogenous agents such as radiation, viruses, and a variety of chemicals, has been a subject of great scientific interest for a long time. (druglibrary.net)
Male sex1
- A search of a 35-kilobase region of the human Y chromosome necessary for male sex determination has resulted in the identification of a new gene. (nih.gov)
Sets of chromosomes2
- The study of whole sets of chromosomes is sometimes known as karyology. (wikipedia.org)
- Euploidy is a condition in which an organism possesses one or more full sets of chromosomes. (biologyideas.com)
Common chromosomal1
- Trisomy 21, also referred to as Down's syndrome, is a chromosomal aberration characterized by the presence of an additional chromosome 21.Trisomy 21 is associated with a rate of incidence of 1:600 among newborns and is one of the most common chromosomal … However, they can also have detrimental effects. (solarpoultry.com)
Syndrome6
- Trisomy 21 → gain of an extra chromosome 21, results in Down's syndrome. (mindmeister.com)
- Testosterone is determined in men when reduced testosterone production is suspected, e.g. in hypogonadism, estrogen therapy, chromosome aberrations (as in the Klinefelter's syndrome) and liver cirrhosis. (cdc.gov)
- Ten cases with known cryptic aberrations were selected (seven cases with subtelomeric rearrangements, one case with an interstitial deletion and two cases with microdeletion syndromes: one case with DiGeorge syndrome and one case with a microdeletion of 17p11 (Smith Magenis syndrome) in 60% of the lymphocytes). (bmj.com)
- Y-chromosome microdeletion syndrome occurs in approximately 7,5% of males with confirmed infertility. (cloudhealthlabs.com)
- This mosaicism, due to the presence of the ring Y chromosome and depending upon on the presence or absence of the SRY gene can result in a wide spectrum of manifestations ranging from females with a Turner syndrome-like phenotype to phenotypic males. (juniperpublishers.com)
- Down Syndrome - Extra chromosome at position 21. (solarpoultry.com)
Eukaryotic chromosome2
- Each eukaryotic chromosome contains a linear DNA with two ends. (oracleias.org)
- Telomere is present in the tip of eukaryotic chromosome. (oracleias.org)
Chromatids2
- In schematic karyograms, just one of the sister chromatids of each chromosome is generally shown for brevity, and in reality they are generally so close together that they look as one on photomicrographs as well unless the resolution is high enough to distinguish them. (wikipedia.org)
- This consists of a failure in the chromosome pairs or the chromatids to separate in the first or second meiotic divisions or during mitosis. (solarpoultry.com)
Mitosis1
- Because of the instability of a ring Y chromosome during mitosis, a second monosomic cell line is often present in these patients [ 2 ]. (juniperpublishers.com)
Humans3
- In the germ-line (the sex cells) the chromosome number is n (humans: n = 23).p28 Thus, in humans 2n = 46. (wikipedia.org)
- Humans have one pair fewer chromosomes than the great apes. (wikipedia.org)
- It causes due to non-disjunction of chromosomes e.g. in humans, 46 chromosome is a diploid condition. (biologyideas.com)
Extra X chromosome2
- [ 9 ] Consequences of an extra X chromosome, usually acquired through a nondisjunctional error during parental gametogenesis, include hypogonadism, gynecomastia, and psychosocial behavioral concerns. (medscape.com)
- All major areas of development, including expressive and receptive language and coordination, are affected by extra X chromosome material. (medscape.com)
MeSH1
- Chromosome Duplication" is a descriptor in the National Library of Medicine's controlled vocabulary thesaurus, MeSH (Medical Subject Headings) . (harvard.edu)
Probes4
- Isolation and characterization of Y chromosome DNA probes. (barrowneuro.org)
- and Golbus, M S, "Isolation and characterization of Y chromosome DNA probes. (barrowneuro.org)
- Comparison of the human with the sheep genomes by use of human chromosome-specific painting probes. (cnr.it)
- 3- 16 However, these probes only reveal chromosome rearrangements located in the subtelomeric region. (bmj.com)
Infertility1
- Gonadal development is particularly susceptible to each additional X chromosome, resulting in seminiferous tubule dysgenesis and infertility, as well as hypoplastic and malformed genitalia, as seen in polysomy X males. (medscape.com)
Hypogonadism1
- The major consequences of the extra sex chromosome, usually acquired through an error of nondisjunction during parental gametogenesis, include hypogonadism, gynecomastia, and psychosocial problems. (medscape.com)
Pairs2
- For example, the legumes Lotus tenuis and Vicia faba each have six pairs of chromosomes, yet V. faba chromosomes are many times larger. (wikipedia.org)
- General designation for syndromes due to chromosomal aberrations, typically associated with mental … Thus, there are normally 23 pairs of chromosomes in the fertilized egg. (solarpoultry.com)
Chromosomal arms1
- The formation of a ring Y chromosome involves terminal breakage in both chromosomal arms (p and q arms) and fusion of the resulting ends with loss of the deleted distal material ( Figure 1 ). (juniperpublishers.com)
Deoxyribonucleic acid1
- It includes a small number of papers dealing with the detailed mechanism of the action of LSD on the deoxyribonucleic acid (DNA), the most important constituent of the chromosomes. (druglibrary.net)
Heredity1
- In his famous textbook The Cell in Development and Heredity , Wilson linked together the independent work of Boveri and Sutton (both around 1902) by naming the chromosome theory of inheritance the Boveri-Sutton chromosome theory (the names are sometimes reversed). (wikipedia.org)
Numerical2
- The change in the number of chromosomes is called chromosomal numerical aberration . (biologyideas.com)
- Chromosomal disorders: numerical disorders The most frequent cause of numerical disorders in chromosomes tends to be n ondisjunction. (solarpoultry.com)
Lymphocytes1
- Before observing SCE's in chemically treated lymphocytes the spontaneous SCE frequency in human lymphocytes was investigated for natural variation eg due to donor age or sex differences. (soton.ac.uk)
Human6
- Human chromosome 2 appears to have resulted from the fusion of two ancestral chromosomes, and many of the genes of those two original chromosomes have been translocated to other chromosomes. (wikipedia.org)
- The long series of GA repeats in Y5, anticipated to be polymorphic, may provide a sensitive means to follow Y chromosome variation in human populations. (barrowneuro.org)
- ZOO-FISH and R-banding reveal extensive conservation of human chromosome regions in euchromatic regions of river buffalo chromosomes. (cnr.it)
- The Human-Specific BOLA2 Duplication Modifies Iron Homeostasis and Anemia Predisposition in Chromosome 16p11.2 Autism Individuals. (harvard.edu)
- This section publishes research on the variety and impact of chromosomal aberrations on all types of human cancer. (biomedcentral.com)
- Known human disorders include Charcot-Marie-Tooth disease type 1A, which may be caused by duplication of the gene encoding peripheral myelin protein 22 (PMP22) on chromosome 17. (solarpoultry.com)
Alterations1
- for uncertain chromosomes, "c" for constitutional alterations. (cydas.org)
Constitutional2
Polyploid1
- Polyploid cells have multiple copies of chromosomes and haploid cells have single copies. (wikipedia.org)
Trisomy 131
- Because of the various life-threatening medical problems surrounding this condition, the majority of infants with trisomy 13 … 12.24, the two resultant telocentric chromosomes may open up to produce chromosomes with two identical arms (i.e., iso-chromosomes). (solarpoultry.com)
Organism3
- Karyotypes describe the chromosome count of an organism and what these chromosomes look like under a light microscope. (wikipedia.org)
- Triploidy is a condition in which an organism contains Three sets (3n) of chromosomes in the nucleus of the body cell. (biologyideas.com)
- Polyploidy is a condition in which an organism contains more than usual two sets (2n) of chromosomes . (biologyideas.com)
Theory of inheritance1
- Walter Sutton (left) and Theodor Boveri (right) independently developed the chromosome theory of inheritance in 1902. (wikipedia.org)
MAMMALIAN1
- Moreover, a reliable in vitro study (Murie and Innes, 1997 K3 CSR) is available in which the potential of LAS Na to cause chromosomal aberrations in mammalian cells was examined. (europa.eu)
Germ cells1
- The mechanisms of transmission of both discontinuous and continuous characteristics across the generations were unknown before Mendel's laws were explained at the turn of the 20th Century by the behavior of chromosomes in germ cells [ 2 , 3 ]. (biomedcentral.com)
MOSAICISM1
- He has history of ring Y chromosome mosaicism diagnosed by amniocentesis performed due to advanced maternal age. (juniperpublishers.com)
Replication1
- Prokaryotic chromosome contains only a single origin of replication and can occur at any stage of life cycle. (oracleias.org)
Translocation1
- Despite the large chromosome fragments involved in the unbalanced translocation in this case, repeated standard G-band analysis could not reveal this rearrangement due to the similarity in the banding pattern of the chromosome fragments involved. (bmj.com)
Vitro1
- In this case, possible clastogenicity is examined in an in vitro and in vivo chromosome aberration study and therefore not considered necessary in the Ames test. (europa.eu)
Males1
- Sex chromosomes determine an individual's sex: females have two X chromosomes (XX), and males have an X and a Y chromosome (XY). (solarpoultry.com)
Breakage1
- DNA intercalation leads to chromosome breakage rather than SCE. (soton.ac.uk)
Cells7
- The sex of an unborn fetus can be predicted by observation of interphase cells (see amniotic centesis and Barr body). (wikipedia.org)
- Fluorescence and Giemsa banding studies of the allocyclic X chromosome in embryonic and adult mouse cells. (wikidata.org)
- [5] In animal cells, chromosomes reach their highest compaction level in anaphase during chromosome segregation . (wikipedia.org)
- Some use the term chromosome in a wider sense, to refer to the individualized portions of chromatin in cells, either visible or not under light microscopy. (wikipedia.org)
- FISH analysis demonstrated the presence of a ring Y chromosome in 37.1% of the cells. (juniperpublishers.com)
- The result is that some cells have the normal number of 46 chromosomes, and other cells have more (47) or fewer (45) chromosomes. (solarpoultry.com)
- Chromosomes are structures within cells that contain DNA and many genes. (solarpoultry.com)