Sawamura K, Taira T, Watanabe T K
Department of Genetics, Graduate University for Advanced Studies, National Institute of Genetics, Shizuoka, Japan.
Genetics. 1993 Feb;133(2):299-305. doi: 10.1093/genetics/133.2.299.
Hybrid females from Drosophila simulans females x Drosophila melanogaster males die as embryos while hybrid males from the reciprocal cross die as late larvae. The other two classes are sterile adults. Letting C, X, and Y designate egg cytoplasm, X, and Y chromosomes, respectively, and subscripts m and s stand for melanogaster and simulans, CmXmYs males are lethal in the larval stage and are rescued by the previously reported genes, Lhr (Lethal hybrid rescue) in simulans or Hmr (Hybrid male rescue) in melanogaster. We report here another rescue gene located on the second chromosome of simulans, mhr (maternal hybrid rescue) that, when present in the mother, rescues CsXmXs females from embryonic lethality. It has been postulated that the hybrids not carrying the Xs like CmXmYs males are larval lethal and that the hybrids carrying both the Cs and the Xm like CsXmXs females are embryonic lethal. According to these postulates CsXmYs males (obtained by mating attached-X simulans females to melanogaster males) should be doubly lethal, at both embryo and larval stages. When both rescuing genes are present, Hmr in the father and mhr in the mother, males of this genotype are fully viable, as predicted.
黑腹果蝇雄蝇与拟暗果蝇雌蝇杂交产生的杂种雌性胚胎期死亡，而反交产生的杂种雄性在幼虫后期死亡。另外两类是不育的成虫。分别用C、X和Y代表卵细胞质、X染色体和Y染色体，下标m和s分别代表黑腹果蝇和拟暗果蝇，CmXmYs雄性在幼虫期致死，可被先前报道的基因拯救，拟暗果蝇中的Lhr（杂种致死拯救）或黑腹果蝇中的Hmr（杂种雄性拯救）。我们在此报道另一个位于拟暗果蝇第二条染色体上的拯救基因mhr（母本杂种拯救），当它存在于母体中时，可使CsXmXs雌性免于胚胎致死。据推测，像CmXmYs雄性那样不携带Xs的杂种在幼虫期致死，而像CsXmXs雌性那样同时携带Cs和Xm的杂种在胚胎期致死。根据这些推测，CsXmYs雄性（通过将并联X的拟暗果蝇雌蝇与黑腹果蝇雄蝇交配获得）在胚胎期和幼虫期都应该是双重致死的。当两个拯救基因都存在时，即父本中的Hmr和母本中的mhr，这种基因型的雄性完全存活，正如预测的那样。
