The 24 human chromosome territories during prometaphase in fibroblast cells.

Normal members of a particular eukaryotic species all have the same number of nuclear chromosomes (see the table). Other eukaryotic chromosomes, i.e. mitochondrial and plasmid-like small chromosomes, are much more variable in number, and there may be thousands of copies per cell. Binomial name Arabidopsis thaliana (L.) Heynh. ... Binomial name Secale cereale M.Bieb. ... “Corn” redirects here. ... Binomial name Triticum boeoticum Boss. ... Binomial name Triticum aestivum L. Common wheat (also known as bread wheat) is by far the most important wheat species in cultivation today. ... This article is about the product manufactured from Tobacco plants (Nicotiana spp. ... Binomial name Drosophila melanogaster Meigen, 1830 [1] Drosophila melanogaster (from the Greek for black-bellied dew-lover) is a two-winged insect that belongs to the Diptera, the order of the flies. ... Binomial name Cavia porcellus (Linnaeus, 1758) Guinea pigs (also called cavies) are rodents belonging to the family Caviidae and the genus Cavia, originally indigenous to the Andes. ... Subfamilies see article text Feral Rock Pigeon beside Weiming Lake, Peking University Dove redirects here. ... The name snail applies to most members of the molluscan class Gastropoda that have coiled shells. ... Families   Acanthodrilidae   Ailoscolecidae   Alluroididae   Almidae   Criodrilidae   Eudrilidae   Exxidae   Glossoscolecidae   Lumbricidae   Lutodrilidae   Megascolecidae   Microchaetidae   Ocnerodrilidae   Octochaetidae   Sparganophilidae Earthworm is the common name for the largest members of the Oligochaeta (which is either a class or subclass depending on the author) in the phylum Annelida. ... Tibetan Fox (Vulpes ferrilata) Lives at a high plateau of Tibet, bordering on China and India. ... Trinomial name Felis silvestris catus Schreber, 1775 For alternative meanings see cat (disambiguation). ... Binomial name Sus scrofa Linnaeus, 1758 Synonyms Sus domesticus The domestic pig (Sus scrofa domesticus) is usually given the scientific name Sus scrofa, though some authors call it , reserving for the wild boar. ... Binomial name Mus musculus Linnaeus, 1758 Mus musculus is the house mouse. ... Binomial name Mus musculus Linnaeus, 1758 Mus musculus is the house mouse. ... Genera Pentalagus Bunolagus Nesolagus Romerolagus Brachylagus Sylvilagus Oryctolagus Poelagus Rabbits are small mammals in the family Leporidae of the order Lagomorpha, found in several parts of the world. ... Binomial name Mesocricetus auratus Waterhouse, 1839 The Syrian Hamster or Golden Hamster, Mesocricetus auratus, is the best known member of the rodent subfamily Cricetinae, the hamsters. ... Jack rabbit and Jackrabbit redirect here. ... Trinomial name Homo sapiens sapiens Linnaeus, 1758 Humans, or human beings, are bipedal primates belonging to the mammalian species Homo sapiens (Latin: wise man or knowing man) in the family Hominidae (the great apes). ... Type species Troglodytes gorilla Savage, 1847 distribution of Gorilla Species Gorilla gorilla Gorilla beringei The gorilla, the largest of the living primates, is a ground-dwelling omnivore that inhabits the forests of Africa. ... Type species Simia troglodytes Blumenbach, 1775 distribution of Species Pan troglodytes Pan paniscus Chimpanzee, often shortened to chimp, is the common name for the two extant species in the genus Pan. ... “Lamb” redirects here. ... Genera and Species Loxodonta Loxodonta cyclotis Loxodonta africana Elephas Elephas maximus Elephas antiquus † Elephas beyeri † Elephas celebensis † Elephas cypriotes † Elephas ekorensis † Elephas falconeri † Elephas iolensis † Elephas planifrons † Elephas platycephalus † Elephas recki † Stegodon † Mammuthus † Elephantidae (the elephants) is a family of pachyderm, and the only remaining family in the order Proboscidea... Binomial name Bos taurus Linnaeus, 1758 Cattle (often called cows in vernacular and contemporary usage, or kye as the Scots plural of cou) are domesticated ungulates, a member of the subfamily Bovinae of the family Bovidae. ... Binomial name Equus asinus Linnaeus, 1758 For other uses, see Donkey (disambiguation). ... Binomial name Equus caballus Linnaeus, 1758 The horse (Equus caballus, sometimes seen as a subspecies of the Wild Horse, Equus ferus caballus) is a large odd-toed ungulate mammal, one of ten modern species of the genus Equus. ... Trinomial name Canis lupus familiaris The dog (Canis lupus familiaris) is a domestic subspecies of the wolf, a mammal of the Canidae family of the order Carnivora. ... This article or section does not adequately cite its references or sources. ... Trinomial name Carassius auratus auratus (Linnaeus, 1758) For the baked snack crackers, please see Goldfish (snack). ... Superfamilies and families Superfamily Hedyloidea: Hedylidae Superfamily Hesperioidea: Hesperiidae Superfamily Papilionoidea: Papilionidae Pieridae Nymphalidae Lycaenidae Riodinidae A butterfly is an insect of the order Lepidoptera. ... Trypanosoma brucei is a species of parasitic protozoan trypanosomes. ... Image File history File linksMetadata Download high-resolution version (439x612, 117 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Cell nucleus Chromosome Metadata This file contains additional information, probably added from the digital camera or scanner used... Image File history File linksMetadata Download high-resolution version (439x612, 117 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Cell nucleus Chromosome Metadata This file contains additional information, probably added from the digital camera or scanner used... Mouse Embryonic Fibroblasts (MEF) A fibroblast is a type of cell that synthesizes and maintains the extracellular matrix of many animal tissues. ... In biology, a species is one of the basic units of biodiversity. ...

Asexually reproducing species have one set of chromosomes, which is the same in all body cells. It has been suggested that Parthenogenesis be merged into this article or section. ...

Sexually reproducing species have somatic cells (body cells), which are diploid [2n] having two sets of chromosomes, one from the mother and one from the father. Gametes, reproductive cells, are haploid [n]: they have one set of chromosomes. Gametes are produced by meiosis of a diploid germ line cell. During meiosis, the matching chromosomes of father and mother can exchange small parts of themselves (crossover), and thus create new chromosomes that are not inherited solely from either parent. When a male and a female gamete merge (fertilization), a new diploid organism is formed. Sexual reproduction is a union that results in increasing genetic diversity of the offspring. ... A somatic cell is generally taken to mean any cell forming the body of an organism: the word somatic is derived from the Greek word sōma (σώμα), meaning body. Somatic cells, by definition, are not germline cells. ... Ploidy is the number of homologous sets of chromosomes in a biological cell. ... A gamete is a specialized germ cell that fuses with another gamete during fertilization (conception) in organisms that reproduce sexually. ... Ploidy is the number of homologous sets of chromosomes in a biological cell. ... Distinguish from miosis. ... Germline is a word used in biology and genetics. ... Thomas Hunt Morgans illustration of crossing over (1916) Homologous Recombination 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... Categories: Biology stubs ...

Some animal and plant species are polyploid [Xn]: they have more than two sets of homologous chromosomes. Agriculturally important plants such as tobacco or wheat are often polyploid compared to their ancestral species. Wheat has a haploid number of seven chromosomes, still seen in some cultivars as well as the wild progenitors. The more common pasta and bread wheats are polyploid having 28 (tetraploid) and 42 (hexaploid) chromosomes compared to the 14 (diploid) chromosomes in the wild wheat.^[4] Ploidy is the number of homologous sets of chromosomes in a biological cell. ... Homologous chromosomes are chromosomes in a biological cell that pair (synapse) during meiosis, or alternatively, non-identical chromosomes that contain information for the same biological features and contain the same genes at the same loci but possibly different genetic information, called alleles, at those genes. ... This article is about the product manufactured from Tobacco plants (Nicotiana spp. ... Species T. aestivum T. boeoticum T. compactum T. dicoccoides T. dicoccon T. durum T. monococcum T. spelta T. sphaerococcum T. timopheevii References:   ITIS 42236 2002-09-22 For the indie rock group see: Wheat (band). ... This Osteospermum Pink Whirls is a successful cultivar. ... Percentages are relative to US recommendations for adults. ... Percentages are relative to US recommendations for adults. ...

Historical note: In 1921, Theophilus Painter claimed, based on his observations, that human sex cells had 24 chromosomes each, giving humans 48 chromosomes total. It wasn't until 1955 that the number of chromosomes was clearly shown to be 23. This article needs cleanup. ...

Prokaryotes

Prokaryote species generally have one copy of each major chromosome, but most cells can easily survive with multiple copies. Plasmids and plasmid-like small chromosomes are, like in eukaryotes, very variable in copy number. The number of plasmids in the cell is almost entirely determined by the rate of division of the plasmid - fast division causes high copy number, and vice versa. Prokaryotes (pro-KAR-ee-oht) (from Old Greek pro- before + karyon nut or kernel, referring to the cell nucleus, + suffix -otos, pl. ... In biology, a species is one of the basic units of biodiversity. ...

Karyotype

Main article: Karyotype

Figure 3: Karyotype of a human male

Karyotyping is a technique used to determine the (diploid) number of nuclear chromosomes of a eukaryotic organism, and may be used for determining sex and spotting chromosomal abnormalities. Cells can be locked part way through division (in metaphase) in vitro (in a reaction vial) with colchicine. These cells are then stained, photographed and arranged into a karyotype (an ordered set of chromosomes, Fig. 3), also called karyogram. Karyogram of human male using Giemsa staining. ... Image File history File links NHGRI_human_male_karyotype. ... Image File history File links NHGRI_human_male_karyotype. ... Wiktionary has a definition of: In vitro In vitro (Latin: within glass) means within a test tube, or, more generally, outside a living organism or cell. ... Colchicine is a highly deadly poisonous alkaloid, originally extracted from plants of the genus Colchicum (Autumn crocus, also known as the Meadow saffron). Originally used to treat rheumatic complaints and especially gout, it was also prescribed for its cathartic and emetic effects. ... Karyogram of human male using Giemsa staining. ...

Like many sexually reproducing species, humans have special gonosomes (sex chromosomes, in contrast to autosomes). These are XX in females and XY in males, and can be seen in the karyotype, Fig. 3.
The XY sex-determination system is a well-known sex-determination system. ... An autosome is a non-sex chromosome. ...

Chromosomal aberrations

Main articles: Chromosome abnormalities and aneuploidy

The three major single chromosome mutations; deletion (1), duplication (2) and inversion (3).

The two major two-chromosome mutations; insertion (1) and translocation (2).

In Down syndrome, chromosome 21 is affected

Chromosomal aberrations are disruptions in the normal chromosomal content of a cell, and are a major cause of genetic disease in humans, such as Down syndrome. Some chromosome abnormalities do not cause disease in carriers, such as translocations, or chromosomal inversions, although they may lead to a higher chance of having a child with a chromosome disorder. Abnormal numbers of chromosomes or chromosome sets, aneuploidy, may be lethal or give rise to genetic disorders. Genetic counseling is offered for families that may carry a chromosome rearrangement. A chromosome abnormality reflects an abnormality of chromosome number or structure. ... Aneuploidy is a change in the number of chromosomes that can lead to a chromosomal disorder. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Image File history File links Size of this preview: 431 × 599 pixel Image in higher resolution (616 × 856 pixel, file size: 19 KB, MIME type: image/png) By Richard Wheeler (Zephyris) 2007. ... Image File history File links Size of this preview: 431 × 599 pixel Image in higher resolution (616 × 856 pixel, file size: 19 KB, MIME type: image/png) By Richard Wheeler (Zephyris) 2007. ... Image File history File links The human chromosome 21 is affected in Down syndrome. ... Image File history File links The human chromosome 21 is affected in Down syndrome. ... 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. ... Genetic counseling is the process by which patients or relatives, at risk of an inherited disorder, are advised of the consequences and nature of the disorder, the probability of developing or transmitting it, and the options open to them in management and family planning in order to prevent, avoid or...

The gain or loss of chromosome material can lead to a variety of genetic disorders. Human examples include: A genetic disorder, or genetic disease is a disease caused, at least in part, by the genes of the person with the disease. ...

• Cri du chat, which is caused by the deletion of part of the short arm of chromosome 5. "Cri du chat" means "cry of the cat" in French, and the condition was so-named because affected babies make high-pitched cries that sound like a cat. Affected individuals have wide-set eyes, a small head and jaw and are moderately to severely mentally retarded and very short.
• Wolf-Hirschhorn syndrome, which is caused by partial deletion of the short arm of chromosome 4. It is characterized by severe growth retardation and severe to profound mental retardation.
• Down's syndrome, usually is caused by an extra copy of chromosome 21 (trisomy 21). Characteristics include decreased muscle tone, asymmetrical skull, slanting eyes and mild to moderate mental retardation.
• Edward's syndrome, which is the second most common trisomy after Down syndrome. It is a trisomy of chromosome 18. Symptoms include mental and motor retardation and numerous congenital anomalies causing serious health problems. Ninety percent die in infancy; however, those who live past their first birthday usually are quite healthy thereafter. They have a characteristic hand appearance with clenched hands and overlapping fingers.
• Patau Syndrome, also called D-Syndrome or trisomy-13. Symptoms are somewhat similar to those of trisomy-18, but they do not have the characteristic hand shape.
• Idic15, abbreviation for Isodicentric 15 on chromosome 15; also called the following names due to various researches, but they all mean the same; IDIC(15), Inverted dupliction 15, extra Marker, Inv dup 15, partial tetrasomy 15
• Jacobsen syndrome, also called the terminal 11q deletion disorder.[1] This is a very rare disorder. Those affected have normal intelligence or mild mental retardation, with poor expressive language skills. Most have a bleeding disorder called Paris-Trousseau syndrome.
• Klinefelter's syndrome (XXY). Men with Klinefelter syndrome are usually sterile, and tend to have longer arms and legs and to be taller than their peers. Boys with the syndrome are often shy and quiet, and have a higher incidence of speech delay and dyslexia. During puberty, without testosterone treatment, some of them may develop gynecomastia.
• Turner syndrome (X instead of XX or XY). In Turner syndrome, female sexual characteristics are present but underdeveloped. People with Turner syndrome often have a short stature, low hairline, abnormal eye features and bone development and a "caved-in" appearance to the chest.
• XYY syndrome. XYY boys are usually taller than their siblings. Like XXY boys and XXX girls, they are somewhat more likely to have learning difficulties.
• Triple-X syndrome (XXX). XXX girls tend to be tall and thin and are often shy. They have a higher incidence of dyslexia.
• Small supernumerary marker chromosome. This means there is an extra, abnormal chromosome. Features depend on the origin of the extra genetic material. Cat-eye syndrome and isodicentric chromosome 15 syndrome (or Idic15) are both caused by a supernumerary marker chromosome, as is Pallister-Killian syndrome.

Chromosomal mutations produce changes in whole chromosomes (more than one gene) or in the number of chromosomes present. This article does not cite any references or sources. ... A genetic deletion is a genetic aberration in which part of a chromosome is missing. ... Wolf-Hirschhorn syndrome, also known as deletion 4p and 4p- syndrome was first described in 1961 by U. Wolf and K. Hirschhorn and their co-workers. ... A child with Down syndrome Down syndrome (also called Downs syndrome) encompasses a number of genetic disorders, of which trisomy 21 (a nondisjunction) is the most representative, causing highly variable degrees of learning difficulties and physical disabilities. ... Trisomy 18 or Edwards Syndrome (named after John H. Edwards) is a genetic disorder. ... Patau syndrome, also known as trisomy 13, is a chromosomal aberration, a disease in which a patient has an additional chromosome 13 due to a non-disjunction of chromosomes during meiosis. ... To meet Wikipedias quality standards, this article may require cleanup. ... Summary Jacobsen Syndrome, also known as 11q deletion, is a congenital disorder that occurs due to a partial deletion of the terminal band on chromosome 11. ... Not to be confused with XYY syndrome or XXX syndrome. ... Dyslexia is a condition or learning disability which causes difficulty with reading and/or writing, not due to an intelligence below the normal range or to sensory problems such as poor eyesight. ... Gynecomastia, pronounced is the development of abnormally large mammary glands in males resulting in breast enlargement, which can sometimes cause secretion of milk. ... XYY syndrome is an aneuploidy (specifically a trisomy) of the sex chromosomes in which a human male receives an extra Y chromosome, producing a 47,XYY karyotype. ... Triple X syndrome is a chromosomal aneuploid abnormality characterized by the presence of an extra X chromosome in each cell of a human female. ... Humans typically have 22 pairs autosomal chromosomes in our cells, and a pair of sex chromosomes. ... Synonyms CES Schmid-Fraccaro Syndrome Chromosome 22, Partial Tetrasomy (22pter-22q11) Chromosome 22, Partial Trisomy (22pter-22q11) Chromosome 22, Inverted Duplication (22pter-22q11) Cat-eye syndrome is a rare chromosomal disorder that may be evident at birth. ... To meet Wikipedias quality standards, this article may require cleanup. ... Pallister-Killian syndrome (also tetrasomy 12p mosaicism or Pallister mosaic aneuploidy syndrome) is an extremely rare genetic disorder occurring in humans. ...

• Deletion- loss of part of a chromosome
• Duplication- extra copies of a part of a chromosome
• Inversion- reverse the direction of a part of a chromosome
• Translocation- part of a chromosome breaks off and attaches to another chromosome

Most mutations are neutral- have little or no effect

A detailed graphical display of all human chromosomes and the diseases annotated at the correct spot may be found at [2].

The human chromosomes

Human cells have 23 pairs of large linear nuclear chromosomes, giving a total of 46 per cell. In addition to these, human cells have many hundreds of copies of the mitochondrial genome. All of the human chromosomes have been sequenced and a great deal is known about each of them. The mitochondrial genome is the genetic material of the mitochondria. ...

• † Human Genome Project goals called for determination of only the euchromatic portion of the genome. Telomeres, centromeres, and other heterochromatic regions have been left undetermined, as have a small number of unclonable gaps.^[5]

See also

• Locus (explains gene location nomenclature)
• Sex-determination system
  • XY sex-determination system
    • X chromosome
      • X-inactivation
    • Y chromosome
      • Y-chromosomal Adam
      • Y-chromosomal Aaron
• Genetic genealogy
  • Genealogical DNA test
• Genetic deletion
• List of number of chromosomes of various organisms

External links

• What Can Our Chromosomes Tell Us?,an accessible and comprehensive look at chromosomes, from the University of Utah's Genetic Science Learning Center
• Try making a karyotype yourself, from the University of Utah's Genetic Science Learning Center
• Kimballs Chromosome pages
• Chromosome News from Genome News Network
• European Chromosome 11q Network
• Eurochromnet, European network for Rare Chromosome Disorders on the Internet
• http://www.ensembl.org Ensembl project, presenting chromosomes, their genes and syntenic loci graphically via the web
• [Genographic Project]
• A Yahoo! group for Isodicentric 15

References

1. ^ Bogin, Barry, Edward Alcamo, Curtis Chubb, William J. Ehmann, Mark R. Feil, David R. Hershey, Mitchell Leslie, Karel F. Liem, William Thwaites, and Salvatore Tocci. Austin: Holt, Rinehart, and Winston, 1999. 146.
2. ^ Bogin, Barry, Edward Alcamo, Curtis Chubb, William J. Ehmann, Mark R. Feil, David R. Hershey, Mitchell Leslie, Karel F. Liem, William Thwaites, and Salvatore Tocci. Austin: Holt, Rinehart, and Winston, 1999. 146.
3. ^ Singapore Science Center ScienceNet, accessed January 30, 2007
4. ^ Sakamura, T. (1918), Kurze Mitteilung uber die Chromosomenzahlen und die Verwandtschaftsverhaltnisse der Triticum-Arten. Bot. Mag., 32: 151-154.
5. ^ http://www.ncbi.nlm.nih.gov/genome/seq/