Functional Analysis on the sex-related genes using the inter-specific hybrids among Oryzias fishes.

用Hd-rR品系的雌性青鳉与雄性弯尾青鳉进行种间杂交，XY鱼均发育为雌性，而用HO 4C品系的雌性青鳉进行杂交，没有出现性反转现象。利用HdrR和HO 4C之间的多态性，我们进行了连锁分析，以发现一个位点（hml）的连锁群17负责性逆转。Dmy基因在杂种中的表达分析表明，性反转是由于Dmy基因在性别决定阶段表达量下降所致，表明hml基因与Dmy基因的表达调控有关。hml的精细定位将17号染色体上的基因座区域缩小到624 KB。我们仍在继续研究如何鉴定人类白细胞瘤。

Inter-specific hybrids between female of Hd-rR strain of medaka and male Oryzias curvinotus, all XY fish developed into females, but when we used females of HO4C strain of medaka for hybridization, no sex-reversals appeared. Utilizing the polymorphism between HdrR and HO4C, we conducted a linkage analysis to uncover a locus(hml) on the linkage group 17 responsible for the sex reversal. The analysis of the expression of Dmy in the hybrid revealed that the sex-reversal resulted from the decrease of the expression of Dmy during the sex-determining stage, indicating that hml is related to the regulation of Dmy expression. Fine mapping for hml narrowed the region of the locus on the chromosome 17 to 624 KB. We are continuing the study for the identification of hml.