Recurrent Turnover of Chromosome-Specific Satellites in Drosophila
Recurrent Turnover of Chromosome-Specific Satellites in Drosophila
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DOI：
10.1093/gbe/evu104
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发表时间：
2014-06-01
影响因子：
3.3
通讯作者：
Gallach, Miguel
中科院分区：
文献类型：
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作者：
Gallach, Miguel
重复DNA是在基因组中重复多次的DNA序列，通常被认为是无功能的。一些研究预测，染色体特异性卫星的快速进化导致了杂交不相容性和物种形成。有趣的是，在果蝇中，X染色体和点染色体有一个独特而值得注意的特性：它们由染色体特异性结合蛋白识别，并且它们特别涉及密切相关物种之间的遗传不相容性。在这里，我表明，X和点染色体是由某些重复的元素，在果蝇物种进行经常性营业额过剩。X染色体和圆点染色体被这些随体覆盖的部分分别是其他染色体的52倍和44倍。此外，D. pseudobscura（染色体臂XR）已经被定殖祖先X染色体（染色体臂XL）的相同卫星侵入，而其他物种中的常染色体同源物仍然大多缺乏卫星。因此，D. ananassae，与D.与其他染色体相比，黑腹果蝇没有过多的DNA序列。这些卫星的生物学和进化模式表明，它们为两条染色体提供了某种结构特征，并受到自然选择的影响。快速的随体更替符合一些物种形成模型，并且可以解释为什么这两条染色体通常参与杂交不亲和性。
Repetitive DNA are DNA sequences that are repeated multiple times in the genome and normally considered nonfunctional. Several studies predict that the rapid evolution of chromosome-specific satellites led to hybrid incompatibilities and speciation. Interestingly, in Drosophila, the X and dot chromosomes share a unique and noteworthy property: They are identified by chromosome-specific binding proteins and they are particularly involved in genetic incompatibilities between closely related species. Here, I show that the X and dot chromosomes are overpopulated by certain repetitive elements that undergo recurrent turnover in Drosophila species. The portion of the X and dot chromosomes covered by such satellites is up to 52 times and 44 times higher than in other chromosomes, respectively. In addition, the newly evolved X chromosome in D. pseudoobscura (the chromosomal arm XR) has been invaded by the same satellite that colonized the ancestral X chromosome (chromosomal arm XL), whereas the autosomal homologs in other species remain mostly devoid of satellites. Contrarily, the Muller element F in D. ananassae, homolog to the dot chromosome in D. melanogaster, has no overrepresented DNA sequences compared with any other chromosome. The biology and evolutionary patterns of the characterized satellites suggest that they provide both chromosomes with some kind of structural identity and are exposed to natural selection. The rapid satellite turnover fits some speciation models and may explain why these two chromosomes are typically involved in hybrid incompatibilities.