Evolution of different Y chromosomes in two medaka species, Oryzias dancena and O-latipes
Evolution of different Y chromosomes in two medaka species, Oryzias dancena and O-latipes
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DOI：
10.1534/genetics.106.068247
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发表时间：
2007-03-01
期刊：
影响因子：
3.3
通讯作者：
Sakaizumi, Mitsuru
中科院分区：
文献类型：
--
作者：
Takehana, Yusuke;Demiyah, Diana;Sakaizumi, Mitsuru
尽管 scx 决定基因 DMY 已在青鳉 (Oryzias latipes) 的 Y 染色体上被发现，但该基因在大多数青鳉物种中不存在，这表明密切相关的物种具有不同的性别决定基因。在这里，我们研究了不具有 DMY 基因的 O. dancena 的性别决定机制。由于该物种尚未报道异形性染色体，因此对通过激素治疗产生的性别逆转个体进行了后代测试。性别逆转的雄性产生全雌性后代，表明 O. dancena 具有 XX/XY 性别决定系统。为了揭示神秘的性染色体，使用在 O. latipes 中建立的表达序列标签 (EST) 筛选与性别相关的 DNA 标记。对分离的性别连锁 EST 的连锁分析表明，O. dancena 的性染色体和 O. latipes 的常染色体之间存在保守的同线性。这些标记的荧光原位杂交（FISH）分析证实这些物种的性染色体不是同源的。这些发现强烈表明O. dancena 和O. latipes 性染色体的独立起源。对O. dancena性别决定区域的进一步分析应该为脊椎动物性别决定机制的进化提供重要的见解。
Although the scx-determining gene DMY has been identified on the Y chromosome in the medaka (Oryzias latipes), this gene is absent in most Oryzias species, suggesting that closely related species have different sex-determining genes. Here, we investigated the sex-determination mechanism in O. dancena, which does not possess the DMY gene. Since heteromorphic sex chromosomes have not been reported in this species, a progeny test of sex-reversed individuals produced by hormone treatment was performed. Sex-reversed males yielded all-female progeny, indicating that O. dancena has an XX/XY sex-determination system. To uncover the cryptic sex chromosomes, sex-linked DNA markers were screened using expressed sequence tags (ESTs) established in O. latipes. Linkage analysis of isolated sex-linked ESTs showed a conserved synteny between the sex chromosomes in O. dancena and an autosome in O. latipes. Fluorescence in situ hybridization (FISH) analysis of these markers confirmed that sex chromosomes of these species are not homologous. These findings strongly suggest an independent origin of sex chromosomes in O. dancena and O. latipes. Further analysis of the sex-determining region in O. dancena should provide crucial insights into the evolution of sex-determination mechanisms in vertebrates.