Dynamics of vertebrate sex chromosome evolution: from equal size to giants and dwarfs
Dynamics of vertebrate sex chromosome evolution: from equal size to giants and dwarfs
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DOI：
10.1007/s00412-015-0569-y
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发表时间：
2015-12
期刊：
影响因子：
1.6
通讯作者：
M. Schartl;M. Schmid;I. Nanda
中科院分区：
文献类型：
--
作者：
M. Schartl;M. Schmid;I. Nanda
已知哺乳动物和鸟类的Y和W染色体很小，因为它们的大部分遗传内容退化，并分别由于缺乏与X或Z的重组而丢失。因此，出现了一幅不断缩小的Y和W的图景，它们最终甚至可能消失。我们回顾了大量关于脊椎动物性染色体的文献，通过仔细观察，特别是鱼类、两栖动物和爬行动物的性染色体，发现其中几个群体的染色体比哺乳动物和鸟类的染色体进化更年轻，认为性染色体注定要缩小的观点是不完整的。在这里，性别决定机制显示出高周转率和新的性染色体反复出现。在许多物种中，Ys和Ws大于它们的X和Z对应物。这带来了关于性染色体进化动力学的有趣观点。可以得出结论，由于重复DNA和转座子的积累，Y和W染色体在其分化的初始阶段可以增加大小。
The Y and W chromosomes of mammals and birds are known to be small because most of their genetic content degenerated and were lost due to absence of recombination with the X or Z, respectively. Thus, a picture has emerged of ever-shrinking Ys and Ws that may finally even fade into disappearance. We review here the large amount of literature on sex chromosomes in vertebrate species and find by taking a closer look, particularly at the sex chromosomes of fishes, amphibians and reptiles where several groups have evolutionary younger chromosomes than those of mammals and birds, that the perception of sex chromosomes being doomed to size reduction is incomplete. Here, sex-determining mechanisms show a high turnover and new sex chromosomes appear repeatedly. In many species, Ys and Ws are larger than their X and Z counterparts. This brings up intriguing perspectives regarding the evolutionary dynamics of sex chromosomes. It can be concluded that, due to accumulation of repetitive DNA and transposons, the Y and W chromosomes can increase in size during the initial phase of their differentiation.