Trisomy 21: Difference between revisions
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Trisomy 21 is the name given to the most common occuring mutation that leads to [[Down' | Trisomy 21 is the name given to the most common occuring mutation that leads to [[Down's syndrome|Down's syndrome]]. "Trisomy" because, due to a nondisjunction event (failed separation of the chromosome), there is an extra copy of chromosome 21 in the gamete. And "21" states that the trisomy occurs on chromosome 21. | ||
The non-disjuntion event describes the failure of the chromosome pairs to separate properly during meiosis, either stage 1 or stage 2, such that one of the gametes will contain 1 chromosome 21 and one will contain 1 more, the latter being the trisomy. | |||
Revision as of 17:44, 19 October 2012
Trisomy 21 is the name given to the most common occuring mutation that leads to Down's syndrome. "Trisomy" because, due to a nondisjunction event (failed separation of the chromosome), there is an extra copy of chromosome 21 in the gamete. And "21" states that the trisomy occurs on chromosome 21.
The non-disjuntion event describes the failure of the chromosome pairs to separate properly during meiosis, either stage 1 or stage 2, such that one of the gametes will contain 1 chromosome 21 and one will contain 1 more, the latter being the trisomy.