Moore D P, Miyazaki W Y, Tomkiel J E, Orr-Weaver T L
Department of Biology, Massachusetts Institute of Technology, Cambridge 02142.
Genetics. 1994 Mar;136(3):953-64. doi: 10.1093/genetics/136.3.953.
We describe a Drosophila mutation, Double or nothing (Dub), that causes meiotic nondisjunction in a conditional, dominant manner. Previously isolated mutations in Drosophila specifically affect meiosis either in females or males, with the exception of the mei-S332 and ord genes which are required for proper sister-chromatid cohesion. Dub is unusual in that it causes aberrant chromosome segregation almost exclusively in meiosis I in both sexes. In Dub mutant females both nonexchange and exchange chromosomes undergo nondisjunction, but the effect of Dub on nonexchange chromosomes is more pronounced. Dub reduces recombination levels slightly. Multiple nondisjoined chromosomes frequently cosegregate to the same pole. Dub results in nondisjunction of all chromosomes in meiosis I of males, although the levels are lower than in females. When homozygous, Dub is a conditional lethal allele and exhibits phenotypes consistent with cell death.
我们描述了一种果蝇突变体，“非此即彼”（Dub），它以条件性、显性方式导致减数分裂不分离。先前在果蝇中分离出的突变体专门影响雌性或雄性的减数分裂，除了对于姐妹染色单体正确黏连所必需的mei-S332和ord基因。Dub的不同寻常之处在于，它几乎只在两性的减数分裂I中导致异常的染色体分离。在Dub突变体雌性中，非交换染色体和交换染色体都会发生不分离，但Dub对非交换染色体的影响更为明显。Dub会略微降低重组水平。多条不分离的染色体经常共同分离到同一极。Dub导致雄性减数分裂I中所有染色体的不分离，尽管其程度低于雌性。当纯合时，Dub是一个条件致死等位基因，并表现出与细胞死亡一致的表型。
