Recombination and maternal age-dependent nondisjunction: molecular studies of trisomy 16.
Recombination and maternal age-dependent nondisjunction: molecular studies of trisomy 16.
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发表时间：
1995-10
影响因子：
9.8
通讯作者：
T. Hassold;Michelle C. Merrill;K. Adkins;'. S. Freeman;S. Sherman
中科院分区：
文献类型：
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作者：
T. Hassold;Michelle C. Merrill;K. Adkins;'. S. Freeman;S. Sherman
16三体是最常见的人类三体，发生在>或= 1%的所有临床公认的怀孕。它被认为是完全依赖于母亲的年龄，因此提供了一个有用的模型，研究协会的母亲年龄和不分离。我们一直在进行一项研究，以确定父母和减数分裂阶段的起源三体16和可能的关联不分离和异常重组。在本报告中，我们总结了62例16三体自然流产的观察结果。所有的三体性都是来自母体的，而且几乎所有的错误都发生在减数分裂I。在遗传重组的研究中，我们观察到与正常的雌性减数分裂相比，在产生三体的减数分裂中重组显著减少。然而，大多数16三体的病例在未分离的染色体之间至少有一个可检测的交叉，这表明它是减少-而不是不存在-重组是重要的诱发因素。此外，我们的数据表明，16三体的交叉分布发生了变化，因为我们很少观察到近端长臂和短臂的交叉。因此，至少对于16三体，母体年龄和三体之间的关联可能是由于减少的重组，特别是在染色体的近端区域。
Trisomy 16 is the most common human trisomy, occurring in > or = 1% of all clinically recognized pregnancies. It is thought to be completely dependent on maternal age and thus provides a useful model for studying the association of increasing maternal age and nondisjunction. We have been conducting a study to determine the parent and meiotic stage of origin of trisomy 16 and the possible association of nondisjunction and aberrant recombination. In the present report, we summarize our observations on 62 spontaneous abortions with trisomy 16. All trisomies were maternally derived, and in virtually all the error occurred at meiosis I. In studies of genetic recombination, we observed a highly significant reduction in recombination in the trisomy-generating meioses by comparison with normal female meioses. However, most cases of trisomy 16 had at least one detectable crossover between the nondisjoined chromosomes, indicating that it is reduced--and not absent--recombination that is the important predisposing factor. Additionally, our data indicate an altered distribution of crossing-over in trisomy 16, as we rarely observed crossovers in the proximal long and short arms. Thus, it may be that, at least for trisomy 16, the association between maternal age and trisomy is due to diminished recombination, particularly in the proximal regions of the chromosome.