Evolution of ZZ/ZW and XX/XY sex-determination systems in the closely related medaka species, Oryzias hubbsi and O-dancena
Evolution of ZZ/ZW and XX/XY sex-determination systems in the closely related medaka species, Oryzias hubbsi and O-dancena
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DOI：
10.1007/s00412-007-0110-z
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发表时间：
2007-10-01
期刊：
影响因子：
1.6
通讯作者：
Sakaizumi, Mitsuru
中科院分区：
文献类型：
--
作者：
Takehana, Yusuke;Naruse, Kiyoshi;Sakaizumi, Mitsuru
Y染色体上的一个dm结构域基因被鉴定为水稻的性别决定基因，并命名为DMY（也称为dmrt1bY）。然而，这一基因在大多数米子鱼中都不存在，这表明与米子鱼密切相关的物种有另一种决定性别的基因。事实上，已经证明舞蹈花的Y染色体与拉丁花的Y染色体并不同源，而这两个物种都有一个XX/XY性别决定系统。通过性别反转鱼的后代测试和分离的性别连锁DNA标记的连锁分析，我们发现O. hubbsi是与O. dancena亲缘关系最近的物种之一，具有ZZ/ZW系统。此外，性别连锁标记的遗传和荧光原位杂交图谱显示，O. hubbsi和O. dancena的性染色体不是同源的，表明它们的ZW和XY性染色体的起源不同。此外，我们发现O. hubbsi在形态上具有异型性染色体，其中W染色体具有4,6-diamidino-2-phenylindole （DAPI）阳性的异染色质块，并且比Z染色体大，尽管这种分化的性染色体在其他稻属物种中未被观察到。这些发现表明，多种性别决定机制和性染色体在水稻中已经进化。
A DM-domain gene on the Y chromosome was identified as the sex-determining gene in the medaka, Oryzias latipes, and named DMY (also known as dmrt1bY). However, this gene is absent in most Oryzias fishes, suggesting that closely related species have another sex-determining gene. In fact, it has been demonstrated that the Y chromosome in O. dancena is not homologous to that in O. latipes, whereas both species have an XX/XY sex-determination system. Through a progeny test of sex-reversed fish and a linkage analysis of isolated sex-linked DNA markers, we show that O. hubbsi, which is one of the most closely related species to O. dancena, has a ZZ/ZW system. In addition, genetic and fluorescence in situ hybridization mapping of the sex-linked markers revealed that sex chromosomes in O. hubbsi and O. dancena are not homologous, indicating different origins of these ZW and XY sex chromosomes. Furthermore, we found that O. hubbsi has morphologically heteromorphic sex chromosomes, in which the W chromosome has 4,6-diamidino-2-phenylindole (DAPI)-positive heterochromatin blocks and is larger than the Z chromosome, although such differentiated sex chromosomes have not been observed in other Oryzias species. These findings suggest that a variety of sex-determining mechanisms and sex chromosomes have evolved in Oryzias.