黑腹果蝇卵母细胞中自发的X染色体减数第一次分裂和减数第二次分裂不分离事件具有不同的重组历史。
Spontaneous X chromosome MI and MII nondisjunction events in Drosophila melanogaster oocytes have different recombinational histories.
作者信息
Koehler K E, Boulton C L, Collins H E, French R L, Herman K C, Lacefield S M, Madden L D, Schuetz C D, Hawley R S
机构信息
Department of Genetics, University of California at Davis 95616, USA.
出版信息
Nat Genet. 1996 Dec;14(4):406-14. doi: 10.1038/ng1296-406.
Recent studies of human oocytes have demonstrated an enrichment for distal exchanges among meiosis I (MI) nondisjunction events and for proximal exchanges among meiosis II (MII) events. Our characterization of 103 cases of spontaneous X chromosome nondisjunction in Drosophila oocytes strongly parallels these observations. The recombinational histories of MI (97/103) and MII (6/103) nondisjunctional ova were strikingly different. MI nondisjunction occurred primarily in oocytes with non-exchange X chromosomes; of the new nondisjoining exchange bivalents, most carried distal crossovers. Thus, spontaneous MI nondisjunction reflects the failure of the achiasmate segregation systems. MII nondisjunction occurred only in oocytes with proximal exchanges. We propose several models to explain how very proximal exchanges might impair proper segregation.
近期对人类卵母细胞的研究表明，在减数分裂I（MI）不分离事件中远端交换富集，而在减数分裂II（MII）事件中近端交换富集。我们对果蝇卵母细胞中103例自发性X染色体不分离的特征描述与这些观察结果非常相似。MI（97/103）和MII（6/103）不分离卵的重组历史显著不同。MI不分离主要发生在具有非交换X染色体的卵母细胞中；在新的不分离交换二价体中，大多数携带远端交叉。因此，自发性MI不分离反映了无交叉分离系统的失败。MII不分离仅发生在具有近端交换的卵母细胞中。我们提出了几个模型来解释非常近端的交换可能如何损害正确的分离。
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