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

对青冈近缘种的比较基因组分析表明，即使在亲缘关系较近的物种中，性染色体和性别决定基因在不同物种之间也是不同的，但宽叶野生稻和曲纹野生稻除外。宽叶野生稻和普通野生稻的性染色体均为连锁群(Lg)01，均具有XX-XY性别决定系统。吕宋野生稻的性染色体与宽叶野生稻LG12同源，其性别决定系统为XX-XY。巨型野生稻的性染色体与LG02同源，其性别决定系统为XX-XY。爪哇野生稻和哈布里野生稻的性染色体分别与LG16和LG05同源，性别决定系统为ZZ-ZW。这是首次在水稻近缘种中描述ZZ-ZW性别决定系统。Dancena的性染色体与LG10同源，性别决定系统为XX-XY。从系统发育的角度来看，宽叶野生稻、曲叶野生野生稻、吕州野生野生稻和湄公河流域野生野生稻是单系进化的物种，爪哇野生野生稻、哈布里野生野生稻和亚洲野生野生稻是爪哇种群的共同祖先(爪哇亚种)，而亚洲亚种是最基本的分化种。这些结果表明爪哇亚种群的共同祖先可能具有XX-XY性别决定系统和ZZ-ZW系统，从而导致爪哇亚种和哈布里亚种的进化。青冈近缘种的全球共性相互保存得很好。

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.