Sawamura K, Yamamoto M T
Department of Genetics, Graduate University for Advanced Studies, National Institute of Genetics, Shizuoka, Japan.
Mol Gen Genet. 1993 Jun;239(3):441-9. doi: 10.1007/BF00276943.
Hybrid females from crosses between Drsophila melanogaster males and females of its sibling species, D. simulans, D. mauritiana, or D. sechellia die as embryos. This lethality is believed to be caused by incompatibility between the X chromosome of D. melanogaster and the maternal cytoplasm. Zygotic hybrid rescue (Zhr) prevents this embryonic lethality and has been cytogenetically mapped to a proximal region of the X chromosome of D. melanogaster, probably in the centromeric heterochromatin. We have carried out high resolution cytological mapping of Zhr using deficiencies and duplications of the X heterochromatin. Deletions of the Zhr+ gene from the hybrid genome exhibit the Zhr phenotype. On the contrary, addition of the wild-type gene to the hybrid genome causes embryonic lethality, regardless of sex. The Zhr locus has been narrowed down to the region covered by Dp(1;f)1162 but not covered Dp(1;f)1205, a chromosome carrying a duplication of heterochromatin located slightly distal to the In(1)sc8 heterochromatic break-point.
在黑腹果蝇雄性与它的近缘物种（拟果蝇、毛里求斯果蝇或塞舌尔果蝇）雌性杂交产生的杂种雌性胚胎会死亡。这种致死性被认为是由黑腹果蝇的X染色体与母体细胞质之间的不相容性引起的。合子杂种拯救（Zhr）可防止这种胚胎致死性，并且已通过细胞遗传学方法定位到黑腹果蝇X染色体的近端区域，可能位于着丝粒异染色质中。我们利用X异染色质的缺失和重复对Zhr进行了高分辨率的细胞学定位。从杂种基因组中缺失Zhr +基因会表现出Zhr表型。相反，将野生型基因添加到杂种基因组中会导致胚胎致死，无论性别如何。Zhr基因座已被缩小到由Dp(1;f)1162覆盖但未被Dp(1;f)1205覆盖的区域，Dp(1;f)1205是一条染色体，其携带的异染色质重复位于In(1)sc8异染色质断点稍远的位置。
