Different origins of bird and reptile sex chromosomes inferred from comparative mapping of chicken Z-linked genes
Different origins of bird and reptile sex chromosomes inferred from comparative mapping of chicken Z-linked genes
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DOI：
10.1159/000103169
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发表时间：
2007-01-01
影响因子：
1.7
通讯作者：
Matsuda, Y.
中科院分区：
文献类型：
--
作者：
Kawai, A.;Nishida-Umehara, C.;Matsuda, Y.
鸡基因组计划的最新进展表明，鸟类ZW和哺乳动物XY性染色体来源于共同祖先的不同常染色体对;然而，鸟类和爬行动物性染色体之间的进化关系仍然不清楚。中华鳖（Pelodiscus sinensis）具有遗传性别决定作用，但尚未发现明显的性染色体。为了进一步研究这一点，我们对该物种进行了分子细胞遗传学分析，从而确定了ZZ/ZW型微小性染色体。此外，我们从三个爬行动物物种中克隆了鸡Z-连锁基因的爬行动物同源物，中国甲鱼和日本四纹鼠蛇（Elaphe quadrivirgata）具有异形性染色体，和暹罗鳄（Crocodylus siamensis），表现出温度依赖性性别决定和缺乏性染色体。然后，我们使用FISH将它们映射到每个物种的染色体上。这些基因的连锁在所有物种中都是高度保守的：鸡的Z染色体对应于海龟的6 q染色体、蛇的2 p染色体和鳄鱼的3号染色体。这三个物种的基因顺序是相同的。鸟类Z染色体与蛇和龟的Z性染色体之间缺乏同源性，这表明鸟类和爬行动物的性染色体起源和性别决定的致病基因是不同的。版权所有（c）2007 S. Karger AG，巴塞尔
Recent progress of chicken genome projects has revealed that bird ZW and mammalian XY sex chromosomes were derived from different autosomal pairs of the common ancestor; however, the evolutionary relationship between bird and reptilian sex chromosomes is still unclear. The Chinese soft-shelled turtle (Pelodiscus sinensis) exhibits genetic sex determination, but no distinguishable ( heteromorphic) sex chromosomes have been identified. In order to investigate this further, we performed molecular cytogenetic analyses of this species, and thereby identified ZZ/ZW-type micro-sex chromosomes. In addition, we cloned reptile homologues of chicken Z-linked genes from three reptilian species, the Chinese soft-shelled turtle and the Japanese four-striped rat snake (Elaphe quadrivirgata) which have heteromorphic sex chromosomes, and the Siam crocodile (Crocodylus siamensis), which exhibits temperature-dependent sex determination and lacks sex chromosomes. We then mapped them to chromosomes of each species using FISH. The linkage of the genes has been highly conserved in all species: the chicken Z chromosome corresponded to the turtle chromosome 6q, snake chromosome 2p and crocodile chromosome 3. The order of the genes was identical among the three species. The absence of homology between the bird Z chromosome and the snake and turtle Z sex chromosomes suggests that the origin of the sex chromosomes and the causative genes of sex determination are different between birds and reptiles. Copyright (c) 2007 S. Karger AG, Basel