Davis A W, Noonburg E G, Wu C I
Department of Ecology and Evolution, University of Chicago, Illinois 60637.
Genetics. 1994 May;137(1):191-9. doi: 10.1093/genetics/137.1.191.
F1 hybrid females between the sibling species Drosophila simulans, Drosophila mauritiana and Drosophila sechellia are completely fertile. However, we have found that female sterility can be observed in F2 backcross females who are homozygous for D. simulans X chromosomes and homozygous for autosomal regions from either D. mauritiana or D. sechellia. Our results indicate that neither D. mauritiana autosome (2 or 3) can cause complete female sterility in a D. simulans background. The simultaneous presence of homozygous regions from both the second and third chromosomes of D. mauritiana, however, causes nearly complete female sterility which cannot be accounted for by their individual effects. The two autosomes of D. sechellia may show a similar pattern. From the same crosses, we also obtained evidence against a role for cytoplasmic or maternal effects in causing hybrid male sterility between these species. Taken with the results presented elsewhere, these observations suggest that epistatic interactions between conspecific genes in a hybrid background may be the prevalent mode of hybrid sterility between recently diverged species.
近缘物种拟暗果蝇、毛里求斯果蝇和塞舌尔果蝇之间的 F1 杂交雌性完全可育。然而，我们发现，在 F2 回交雌性中可观察到雌性不育现象，这些雌性对于拟暗果蝇的 X 染色体是纯合的，并且对于来自毛里求斯果蝇或塞舌尔果蝇的常染色体区域是纯合的。我们的结果表明，毛里求斯果蝇的任何一条常染色体（2 号或 3 号）都不会在拟暗果蝇的背景中导致完全的雌性不育。然而，毛里求斯果蝇的第二和第三条染色体上纯合区域的同时存在会导致近乎完全的雌性不育，这无法用它们各自的效应来解释。塞舌尔果蝇的两条常染色体可能表现出类似的模式。从相同的杂交实验中，我们还获得了证据，表明细胞质或母体效应在导致这些物种之间的杂交雄性不育中不起作用。结合其他地方呈现的结果，这些观察结果表明，杂交背景下同种基因之间的上位相互作用可能是最近分化物种之间杂交不育的普遍模式。
