Warren A C, Chakravarti A, Wong C, Slaugenhaupt S A, Halloran S L, Watkins P C, Metaxotou C, Antonarakis S E
Science. 1987 Aug 7;237(4815):652-4. doi: 10.1126/science.2955519.
Trisomy 21 usually results from nondisjunction during meiosis I. In order to determine whether nondisjunction results from failure of normal chromosome pairing or premature unpairing, recombination frequencies were estimated between DNA polymorphic markers on the long arm of chromosome 21 in families containing one individual with trisomy 21. The recombination frequencies on chromosomes 21 that had undergone nondisjunction were then compared to those on chromosomes 21 that had disjoined normally. The data indicate that recombination is reduced between DNA markers on nondisjoined chromosomes 21. These results are consistent with the hypothesis that reduced chiasma formation predisposes to nondisjunction, resulting in trisomy 21 in humans.
21三体综合征通常源于减数分裂I期的不分离。为了确定不分离是由于正常染色体配对失败还是过早解对所致，在含有一名21三体个体的家系中，对21号染色体长臂上的DNA多态性标记之间的重组频率进行了估计。然后将发生不分离的21号染色体上的重组频率与正常分离的21号染色体上的重组频率进行比较。数据表明，未分离的21号染色体上的DNA标记之间的重组减少。这些结果与以下假设一致：交叉形成减少易导致不分离，从而在人类中产生21三体综合征。
