Zinn A R, Pohlman J K, Perlman P S, Butow R A
Plasmid. 1987 May;17(3):248-56. doi: 10.1016/0147-619x(87)90033-3.
A pair of yeast strains of opposite mating type was constructed to contain polymorphisms at three loci on the mitochondrial genome--the 21 S rRNA gene, var1, and cob--such that parental and recombinant forms of these genes could be easily detected by Southern blot analysis. These polymorphisms were used to measure in a single cross gene conversions at the 21 S rRNA and var1 loci and a reciprocal recombination at cob. For all three loci, recombination initiates at about the same time, 4 to 6 h after mixing cells, and increases with similar kinetics over a 24-h period. The segregation of parental and recombinant forms of these genes was then followed by pedigree analysis. The results, which show a high variance in the distribution of parental and recombinant forms of all three genes in cells derived from both the first bud and the mother zygote, are consistent with the segregation of a small number of mitochondrial DNA molecules from the zygote to diploid buds. Based on these results and previous experiments of this type, a limited "zone of mixing" of parental mitochondrial DNA molecules probably exists in the zygote. The extent of sampling from this zone, together with the intrinsic properties of the recombination events themselves, is likely to determine the observed pattern of recombination of mitochondrial DNA sequences at the population level.
构建了一对具有相反交配型的酵母菌株，使其线粒体基因组上的三个位点——21S rRNA基因、var1和cob——存在多态性，这样通过Southern印迹分析就可以轻松检测到这些基因的亲本形式和重组形式。这些多态性被用于在单次杂交中测量21S rRNA和var1位点的基因转换以及cob处的 reciprocal 重组。对于所有三个位点，重组大约在混合细胞后4至6小时同时开始，并在24小时内以相似的动力学增加。然后通过谱系分析追踪这些基因的亲本形式和重组形式的分离情况。结果表明，在来自第一个芽和母合子的细胞中，所有三个基因的亲本形式和重组形式的分布存在高度差异，这与少量线粒体DNA分子从合子分离到二倍体芽的情况一致。基于这些结果和此类先前的实验，合子中可能存在亲本线粒体DNA分子的有限“混合区”。从该区域的采样范围，以及重组事件本身的内在特性，可能决定了在群体水平上观察到的线粒体DNA序列重组模式。
