Comparative genomic analysis using inter-specific hybrids between O. luzonensis and 0. curvinotus

比较基因组学分析表明，除青鳉外，青鳉的性染色体和性别决定基因在种与种之间存在差异。latipes和O. curvinotus甚至在密切相关的物种。性染色体。latipes和O.两种鱼均为连锁群（LG）01，均为XX-XY性别决定系统。性染色体。luzonensis是O. curvinotus与O.性决定系统为XX-XY。性染色体。Mekongensis与LG 02同源，性别决定系统为XX-XY。O. javanicus和O.性染色体分别与LG 16和LG 05正交，性决定系统为ZZ-ZW。这是ZZ-ZW性别决定系统在稻属近缘种中的首次描述。性染色体。dancena与LG 10同源，性别决定系统为XX-XY。从系统发育的角度来看，O. latipes、宽叶野百合O. curvinoutus，O. luzonensis和O. mekongnensis为单系（latipes种群），O. javanicus，O. habsi和O. dancena和O. dancena是javanicus种组中最基部分化的种。这些结果表明爪哇种组的共同祖先可能具有XX-XY性别决定系统和ZZ-ZW系统，并在该谱系中进化为O。javanicus和O.哈布西青鳉近缘种间的共线性关系相互保守。

Comparative genomic analysis using medaka related species revealed that the sex chromosomes and sex determination genes differ from species to species except O. latipes and O. curvinotus even in the closely relates species. Sex chromosomes of O. latipes and O. curvinotus were linkage group (LG) 01 and both species had XX-XY sex determination system. Sex chromosome of O. luzonensis, which is the sister species of O. curvinotus, was orthologous to LG12 of O. latipes and its sex determination system was XX-XY. Sex chromosome of O. mekongensis was orthologous to LG02 and its sex determination system was XX-XY. O. javanicus and O. habsi had the sex chromosomes which were orthologous to LG16 and LG05, respectively and their sex determination systems were ZZ-ZW. This is the first description of ZZ-ZW sex determination system in the Oryzias related species. Sex chromosome of O. dancena was orthologous to LG10 and sex determination system was XX-XY. From phylogenetic point of view, O. latipes, O. curvinoutus, O. luzonensis and O. mekongnensis are monophyletic (the latipes species group) and O. javanicus, O. habsi and O. dancena share the common ancestor (the javanicus species group) and O. dancena was the most basally diverged species in the javanicus species group. These results suggest the common ancestor of the javanicus species group might have XX-XY sex determination system and ZZ-ZW system evolved in the lineage leading to O. javanicus and O. habsi. The global synteny of medaka related species were well conserved each other.