Mismatch repair, gene conversion, and crossing-over in two recombination-defective mutants of Drosophila melanogaster.
Mismatch repair, gene conversion, and crossing-over in two recombination-defective mutants of Drosophila melanogaster.
复制标题
果蝇两个重组缺陷突变体中的错配修复、基因转换和交换。
DOI：
--
复制
发表时间：
1982
影响因子：
11.1
通讯作者：
A. T. Carpenter
中科院分区：
文献类型：
--
作者：
A. T. Carpenter
已知两个位点上的重组缺陷突变体会大幅降低减数分裂交叉的频率，但不会降低玫瑰色位点上基因转换的频率。Mei-9突变体产生频繁的减数分裂后分离，表现为花叶后代，而对照和mei-218突变体则不产生花叶后代。结果表明：(1)果蝇的重组涉及到一个双亲本DNA中间体；(2)异双工DNA的校正或双亲本DNA的识别是必要的，但不是充分的，因为这个中间体导致了两侧标记的交叉。因此，至少在果蝇中，meselson - radd型重组分子模型中的异构化步骤可能是受遗传控制的。
Recombination-defective mutants at two loci that are known to decrease drastically the frequency of meiotic crossing-over do not decrease the frequency of gene conversion at the rosy locus. mei-9 mutant alleles produce frequent postmeiotic segregants manifested as mosaic progeny whereas controls and mei-218 mutants produce none. It is concluded that (i) recombination in Drosophila involves a biparental DNA intermediate and (ii) correction of heteroduplex DNA or recognition of biparental DNA or both is necessary, but not sufficient, for this intermediate to result in crossing-over of flanking markers. It is therefore likely, at least in Drosophila, that the isomerization step in Meselson-Radding type molecular models of recombination is under genetic control.