The asymmetry of female meiosis reduces the frequency of inheritance of unpaired chromosomes
The asymmetry of female meiosis reduces the frequency of inheritance of unpaired chromosomes
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DOI：
10.7554/elife.06056
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发表时间：
2015-04-07
期刊：
影响因子：
7.7
通讯作者：
McNally, Francis J.
中科院分区：
文献类型：
--
作者：
Cortes, Daniel;McNally, Karen;McNally, Francis J.
三体，即一条染色体的第三个拷贝的存在，是有害的，并且如果通过生殖系传递，则会导致不能存活或有缺陷的后代。预测额外染色体的随机分离导致来自三体亲本的三体后代的高频率。C.然而，具有X染色体三体性的秀丽线虫的三体后代比预期的要少得多。我们发现额外的X染色体在雌性减数分裂后期I被优先消除。我们利用一个突变体的特定缺陷配对的X染色体作为一个模型，调查对单价遗传的明显偏见。第一，单价体在后期I滞后，它们的运动偏向于皮层和未来的极体。第二，晚滞后的单价体经常被向内的极体收缩环捕获。因此，雌性减数分裂的不对称性可以部分纠正先前存在的三体性。
Trisomy, the presence of a third copy of one chromosome, is deleterious and results in inviable or defective progeny if passed through the germ line. Random segregation of an extra chromosome is predicted to result in a high frequency of trisomic offspring from a trisomic parent. C. elegans with trisomy of the X chromosome, however, have far fewer trisomic offspring than expected. We found that the extra X chromosome was preferentially eliminated during anaphase I of female meiosis. We utilized a mutant with a specific defect in pairing of the X chromosome as a model to investigate the apparent bias against univalent inheritance. First, univalents lagged during anaphase I and their movement was biased toward the cortex and future polar body. Second, late-lagging univalents were frequently captured by the ingressing polar body contractile ring. The asymmetry of female meiosis can thus partially correct pre-existing trisomy.