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Encyclopedia > Karyotype
Karyogram of human male using Giemsa staining.
Karyogram of human male using Giemsa staining.

A karyotype is a man-made arrangement of all the chromosomes of a cell. In normal diploid organisms, autosomal chromosomes are present in two identical copies, although polyploid cells have multiple copies of chromosomes and haploid cells have single copies. The chromosomes are arranged and displayed (often on a photo) in a standard format known as an idiogram: in pairs, ordered by size and position of centromere for chromosomes of the same size. Karyotypes are used to study chromosomal aberrations, and may be used to determine other macroscopically visible aspects of an individual's genotype, such as sex. In order to be able to see the chromosomes and determine their size and internal pattern, they are chemically labelled with a dye ("stained"). The pattern of individual chromosomes is called chromosome banding, whereas the study of whole sets of chromosomes is known as karyology. Image File history File links NHGRI_human_male_karyotype. ... Image File history File links NHGRI_human_male_karyotype. ... A complex of stains specific for the phosphate groups of DNA. Used in Giemsa banding (or G-banding) to stain chromosomes and often used to create a karyotype. ... Figure 1: A representation of a condensed eukaryotic chromosome, as seen during cell division. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hook from Micrographia which is the origin of the word cell. POOP Cells in culture, stained for keratin (red) and DNA (green). ... Diploid (meaning double in Greek) cells have two copies (homologs) of each chromosome (both sex- and non-sex determining chromosomes), usually one from the mother and one from the father. ... An autosome is a non-sex chromosome. ... Polyploidy refers to cells or organisms that contain more than two copies of each of their chromosomes. ... Ploidy is the number of homologous sets of chromosomes in a biological cell. ... This article is about the biological chromosome. ... This article does not cite its references or sources. ... This article or section does not cite its references or sources. ...


Normal human karyotypes contain 22 pairs of autosomal chromosomes and one pair of sex chromosomes. Normal karyotypes for women contain two X chromosomes and are denoted 46,XX; men have both an X and a Y chromosome denoted 46,XY. However, some individuals have other karyotypes with added or missing sex chromosomes, including 47,XYY, 47,XXY, 47,XXX and 45,X. The karyotype 45,Y does not occur, as an embryo without an X chromosome cannot survive. A sex-determination system is a biological system that determines the development of sexual characteristics in an organism. ... Image of a woman on the Pioneer plaque sent to outer space. ... The X chromosome The X chromosome is one of the two sex-determining chromosomes in many animal species, including mammals (the other is the Y chromosome). ... This article concerns how a man differs from women. ... The human Y chromosome is one of two sex chromosomes, it contains the genes that cause testis development, thus determining maleness. ... XYY, or XYY syndrome, is a trisomy of the sex chromosomes in which a human male receives an extra Y chromosome in each cell, hence having a karyotype of 47,XYY. Effects Physical traits XYY syndrome typically causes no unusual physical features or medical problems. ... XXY karyotype Klinefelters syndrome is a condition caused by a chromosome abnormality in males (specifically, a nondisjunction); sufferers have a pair of X sex chromosomes instead of just one. ... Triple X syndrome is a chromosomal aneuploid abnormality characterized by the presence of an extra X chromosome in each cell of a human female. ... Turner syndrome is a human genetic abnormality, caused by a nondisjunction in the sex chromosomes that occur to females (1 out of every 2,500 births). ...

Contents

Types of banding

Molecular genetics employs several techniques to visualize different aspects of chromosomes:

  • G-banding is obtained with Giemsa stain following digestion of chromosomes with trypsin. It yields a series of lightly and darkly stained bands - the dark regions tend to be heterochromatic, late-replicating and AT rich. The light regions tend to be euchromatic, early-replicating and GC rich.
  • R-banding is the reverse of G-banding (the R stands for "reverse"). The dark regions are euchromatic (guanine-cytosine rich regions) and the bright regions are heterochromatic (thymine-adenine rich regions).
  • C-banding: Giemsa binds to constitutive heterochromatin, so it stains centromeres.
  • Q-banding is a fluorescent pattern obtained using quinacrine for staining. The pattern of bands is very similar to that seen in G-banding.
  • T-banding: visualize telomeres.
Karyotype from a human female lymphocyte probed for the Alu sequence using FISH.
Karyotype from a human female lymphocyte probed for the Alu sequence using FISH.

A complex of stains specific for the phosphate groups of DNA. Used in Giemsa banding (or G-banding) to stain chromosomes and often used to create a karyotype. ... Trypsin (EC 3. ... Constitutive heterochromatin domains are sections of DNA. They occur at centromeres and telomeres and consist of repetitive DNA. They are largely transcriptionally silent. ... The centromere is a region of chromosomes with a special sequence and structure. ... Fluorescence induced by exposure to ultraviolet light in vials containing various sized cadmium selenide (CdSe) quantum dots. ... A telomere is a region of highly repetitive DNA at the end of a chromosome that functions as a disposable buffer. ... Image File history File linksMetadata Size of this preview: 800 × 218 pixel Image in higher resolution (2346 × 640 pixel, file size: 218 KB, MIME type: image/jpeg) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Karyotype Metadata This... Image File history File linksMetadata Size of this preview: 800 × 218 pixel Image in higher resolution (2346 × 640 pixel, file size: 218 KB, MIME type: image/jpeg) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Karyotype Metadata This... A scanning electron microscope (SEM) image of a single human lymphocyte. ... An Alu sequence is a short stretch of DNA originally characterized by the action of the Alu restriction endonuclease. ... A metaphase cell positive for the bcr/abl rearrangement using FISH. The chromosomes can be seen in blue. ...

Classic karyotype

In the "classic" (depicted) karyotype, a dye, often Giemsa (G-banding), less frequently Quinacrine, is very used to stain bands on the chromosomes. Giemsa is specific for the phosphate groups of DNA. Quinacrine binds to the adenine-thymine-rich regions. Each chromosome has a characteristic banding pattern that helps to identify them; both chromosomes in a pair will have the same banding pattern. Look up dye in Wiktionary, the free dictionary. ... A complex of stains specific for the phosphate groups of DNA. Used in Giemsa banding (or G-banding) to stain chromosomes and often used to create a karyotype. ... Quinacrine (trade name: Atabrine) is a drug with a number of different medical applications. ... Above is a ball-and-stick model of the inorganic hydrogenphosphate anion (HPO42−). Colour coding: P (orange); O (red); H (white). ... The structure of part of a DNA double helix Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the development and function of living organisms. ... This article or section does not adequately cite its references or sources. ... For the similarly-spelled vitamin compound, see Thiamine Thymine, also known as 5-methyluracil, is a pyrimidine nucleobase. ...


Karyotypes are arranged with the short arm of the chromosome on top, and the long arm on the bottom. Some karyotypes call the short and long arms p and q, respectively. In addition, the differently stained regions and sub-regions are given numerical designations from proximal to distal on the chromosome arms. For example, Cri du chat syndrome involves a deletion on the short arm of chromosome 5. It is written as 46,XX,5p-. The critical region for this syndrome is deletion of 15.2, which is written as 46,XX,del(5)(p15.2).[1] In zootomy, several terms are used to describe the location of organs and other structures in the body of bilateral animals. ... In zootomy, several terms are used to describe the location of organs and other structures in the body of bilateral animals. ... This article does not cite any references or sources. ...


Spectral karyotype (SKY technique)

Spectral karyotype of a human female
Spectral karyotype of a human female

Spectral karyotyping is a molecular cytogenetic technique used to simultaneously visualize all the pairs of chromosomes in an organism in different colors. Fluorescently-labeled probes for each chromosome are made by labeling chromosome-specific DNA with different fluorophores. Because there are a limited number of spectrally-distinct fluorophores, a combinatorial labeling method is used to generate many different colors. Spectral differences generated by combinatorial labeling are captured and analyzed by using an interferometer attached to a fluorescence microscope. Image processing software then assigns a pseudo color to each spectrally different combination, allowing the visualization of the individually colored chromosomes.[2] Spectral karyotype Found on :National Human Genome Research (USA) With the mention : This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... Spectral karyotype Found on :National Human Genome Research (USA) With the mention : This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... A metaphase cell positive for the bcr/abl rearrangement using FISH Cytogenetics is the study of the structure of chromosome material. ... Figure 1: A representation of a condensed eukaryotic chromosome, as seen during cell division. ... Fluorescence induced by exposure to ultraviolet light in vials containing various sized cadmium selenide (CdSe) quantum dots. ... A fluorophore is a component of a molecule which causes a molecule to be fluorescent. ... Interferometry is the applied science of combining two or more input points of a particular data type, such as optical measurements, to form a greater picture based on the combination of the two sources. ... A false color image showing the Chesapeake Bay and the city of Baltimore. ...


This technique is used to identify structural chromosome aberrations in cancer cells and other disease conditions when Giemsa banding or other techniques are not accurate enough.


Chromosome abnormalities

Chromosome abnormalities can be numerical, as in the presence of extra or missing chromosomes, or structural, as in translocations, inversions, large-scale deletions or duplications. Numerical abnormalities, also known as aneuploidy, often occur as a result of nondisjunction during meiosis in the formation of a gamete; trisomies, in which three copies of a chromosome are present instead of the usual two, are common numerical abnormalities. Structural abnormalities often arise from errors in homologous recombination. Both types of abnormalities can occur in gametes and therefore will be present in all cells of an affected person's body, or they can occur during mitosis and give rise to a genetic mosaic individual who has some normal and some abnormal cells. A chromosome abnormality reflects an abnormality of chromosome number or structure. ... Chromosomal translocation of the 4th and 20th chromosome. ... An inversion is a chromosome rearrangement in which a segment of a chromosome is reversed end to end. ... Aneuploidy is a change in the number of chromosomes that can lead to a chromosomal disorder. ... Nondisjunction is the failure of the chromosomes to properly segregate during meiotic or mitotic anaphase, resulting in daughter cells with abnormal numbers of chromosomes. ... Distinguish from miosis. ... A gamete is a specialized germ cell that fuses with another gamete during fertilization (conception) in organisms that reproduce sexually. ... A trisomy means the presence of three (instead of the normal two) chromosomes of a particular numbered type in an organism. ... Chromosomal crossover is the process by which two chromosomes, paired up during Prophase I of meiosis, exchange some distal portion of their DNA. Crossover occurs when two chromosomes, normally two homologous instances of the same chromosome, break and then reconnect but to the different end piece. ... Mitosis is the process in which a cell duplicates its chromosomes to generate two, identical cells. ... ...


Common chromosomal abnormalities that lead to disease include:

  • Turner syndrome results from a single X chromosome (45, X or 45, X0).
  • Klinefelter syndrome, the most common male chromosomal disease, otherwise known as 47, XXY is caused by an extra X on sex chromosome 23.
  • Edwards syndrome is caused by trisomy (three copies) of chromosome 18.
  • Down syndrome, a common chromosomal disease, is caused by trisomy of chromosome 21.
  • Patau syndrome is caused by trisomy of chromosome 13.
  • Also documented are trisomy 8, trisomy 9 and trisomy 16, although the latter generally does not survive to birth.

Some disorders arise from loss of just a piece of one chromosome, including XXY karyotype Klinefelters syndrome is a condition caused by a chromosome abnormality in males (specifically, a nondisjunction); sufferers have a pair of X sex chromosomes instead of just one. ... Trisomy 18 or Edwards Syndrome (named after John H. Edwards who first described the syndrome in 1960) is a genetic disorder. ... A trisomy means the presence of three (instead of the normal two) chromosomes of a particular numbered type in an organism. ... Patau syndrome, also known as trisomy 13, is a chromosomal abnormality, a syndrome in which a patient has an additional chromosome 13 due to a non-disjunction of chromosomes during meiosis. ...

  • Cri du chat (cry of the cat), from a truncated short arm on chromosome 5. The name comes from the babies' distinctive cry, caused by abnormal formation of the larynx.
  • 1p36 Deletion syndrome, from the loss of part of the short arm of chromosome 1.
  • Angelman syndrome – 50% of cases have a segment of the short arm of chromosome 15 missing.

Chromosomal abnormalities can also occur in cancerous cells of an otherwise genetically normal individual; one well-documented example is the Philadelphia chromosome, a translocation mutation commonly associated with chronic myelogenous leukemia and less often with acute lymphoblastic leukemia. This article does not cite any references or sources. ... 1p36 deletion syndrome is a congenital genetic disorder characterized by moderate to severe intellectual disability, delayed growth, hypotonia, seizures, limited speech ability, malformations,caesiatomi, hearing and vision impairment, and distinct facial features. ... Angelman Syndrome (AS) is a rare neuro-genetic disorder named after an English pediatrician, Dr. Harry Angelman, who first described the syndrome in 1965. ... Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these to spread, either by direct growth into adjacent tissue through invasion, or by implantation into distant sites by metastasis (where cancer cells are transported through the bloodstream or lymphatic system). ... Philadelphia chromosome or Philadelphia translocation is a specific genetic, chromosomal abnormality that is associated with chronic myelogenous leukemia (CML) and involves an exchange of material between chromosomes 9 and 22. ... Chronic myelogenous leukemia (CML) is a form of chronic leukemia characterized by increased and unregulated clonal production of predominantly myeloid cells in the bone marrow. ... Acute lymphoblastic leukemia (ALL), also known as acute lymphocytic leukemia, is a cancer of the white blood cells, characterised by the overproduction and continuous multiplication of malignant and immature white blood cells (referred to as lymphoblasts) in the bone marrow. ...


See also

A genome screen is an overview of which genes are probably related to a certain disease or certain behaviour. ... A graphical representation of the normal human karyotype. ...

References

  1. ^ (2005) in Lisa G. Shaffer, Niels Tommerup: ISCN 2005: An International System for Human Cytogenetic Nomenclature. Switzerland: S. Karger AG. ISBN 3-8055-8019-3. 
  2. ^ E. Schröck, S. du Manoir, T. Veldman, B. Schoell, J. Wienberg, M. A. Ferguson-Smith, Y. Ning, D. H. Ledbetter, I. Bar-Am, D. Soenksen, Y. Garini, T. Ried. Multicolor spectral karyotyping of human chromosomes. Science, 26 July 1996; 273 (5274):494. abstract

July 26 is the 207th day of the year (208th in leap years) in the Gregorian calendar. ... 1996 (MCMXCVI) was a leap year starting on Monday of the Gregorian calendar, and was designated the International Year for the Eradication of Poverty. ...

External links

  • Making a karyotype, an online activity from the University of Utah's Genetic Science Learning Center.
  • Karyotyping activity with case histories from the University of Arizona's Biology Project.
  • Printable karyotype project from Biology Corner, a resource site for biology and science teachers.
  • Chromosome Staining and Banding Techniques
  • Chromosome Banding at opbs.okstate.edu

  Results from FactBites:
 
Karyotyping Activity (318 words)
This exercise is a simulation of human karyotyping using digital images of chromosomes from actual human genetic studies.
A karyotype analysis usually involves blocking cells in mitosis and staining the condensed chromosomes with Giemsa dye.
Karyotyping is one of many techniques that allow us to look for several thousand possible genetic diseases in humans.
Karyotype - Wikipedia, the free encyclopedia (680 words)
Karyotypes are examined in searches for chromosomal aberrations, and may be used to determine other macroscopically visible aspects of an individual's genotype, such as sex (XX vs. XY pair).
In the "classic" (depicted) karyotype, a dye, often Giemsa, is used to stain bands on the chromosomes.
Spectral karyotyping is a molecular cytogenetic technique used to simultaneously visualize all the pairs of chromosomes (23 in humans) in different colors.
  More results at FactBites »

 
 

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