Isochromosome

Isochromosome

An isochromosome is a chromosome that has lost one of its arms and replaced it with an exact copy of the other arm[1]. This is sometimes seen in some females with Turner syndrome or in tumor cells. This may also cause an isochromosome to have two centromeres (Tobias, 2011)

Isochromosome.gif

The chromosome arm is already copied during S phase of the cell cycle. During mitosis (or meiosis I or II), the sister chromatid sets line up along the midline in metaphase. The affected chromosome simply lines up at a right angle to its normal position, and as anaphase begins, the centromere is divided in the opposite plane from all the other chromosomes. This leaves the two long arms together and the two short arms together. The two new mirror-image chromosomes are pulled into opposite daughter cells. This produces two cells, each lacking one arm (e.g. the short arm) and containing an extra arm (e.g. the long arm) of the affected chromatid (or vice versa).It can also be formed by exchange involving one arm of a chromosome and its homolog(or sister chromatid)at the proximal edge of the arm,adjacent to the centromere.

If the chromosomal material contains imprinted genes, there will either be a deletion or duplication of the genetic material (genes on the arm lost are deleted, genes on the arm mirrored are duplicated).

Essential Medical Genetics by Edward S. Tobias, Michael Conner and Malcolm Ferguson-Smith, Wiley-Blackwell 2011


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Look at other dictionaries:

  • isochromosome — isochromosome. См. изохромосома. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • isochromosome — izochromosoma statusas T sritis augalininkystė apibrėžtis Lygiapetė chromosoma su tapačiais genais pečiuose. atitikmenys: angl. isochromosome rus. изохромосома …   Žemės ūkio augalų selekcijos ir sėklininkystės terminų žodynas

  • isochromosome — A chromosome produced following an error in meiosis, in which the two arms are mirror images of each other. The presence of an isochromosome results in the duplication of all genes present on the originating chromosome arm …   Glossary of Biotechnology

  • isochromosome — | ̷ ̷ ̷ ̷+ noun : a chromosome with identical arms believed to be derived from a telocentric chromosome by fusion of two daughter chromosomes * * * isochromosome see iso …   Useful english dictionary

  • isochromosome — noun Date: 1939 a chromosome produced by transverse splitting of the centromere so that both arms are derived from the dyad on one side of the centromere of the parental chromosome and each arm has identical genes arranged in the same order… …   New Collegiate Dictionary

  • isochromosome — adj. [Gr. isos, equal; chromos, color; soma, body] Monocentric or dicentric chromosome with equal and genetically identical arms which are mirror images …   Dictionary of invertebrate zoology

  • isochromosome — noun An abnormal chromosome in which one arm has been lost and replaced with an exact copy of the other arm …   Wiktionary

  • Isochromosome — An abnormal chromosome with two identical arms due to duplication of one arm and loss of the other arm. (Found in some girls with Turner syndrome and in tumors.) * * * A chromosomal aberration that arises as a result of transverse rather than… …   Medical dictionary

  • isochromosome — iso·chromosome …   English syllables

  • intermediate; intermittent; internal; internal medicine; intervention; intestine; involvement of a single lymph node [Ann Arbor staging system for Hodgkin disease]; iodine; ionic current; ionic strength; iris; ischemia; isochromosome; isoleucine; isotope; isotropic; nuclear spin quantum number; regi — electric current; incisor [deciduous]; insoluble; isochromosome; optically inactive …   Medical dictionary

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