Emergence of mammals by emergency : exaptation
Emergence of mammals by emergency : exaptation
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哺乳动物因紧急情况而出现：迁徙
DOI：
10.1111/j.1365-2443.2010.01429.x
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发表时间：
2010
期刊：
影响因子：
2.1
通讯作者：
Nishihara H
中科院分区：
文献类型：
--
作者：
Okada N;Sasaki T;Shimogori T;Nishihara H
随着分子胚胎学的发展和后基因组时代的到来，植物形态进化的分子机制开始被阐明。许多脊椎动物物种的全基因组序列已经确定，比较基因组学表明，生物多样性的一个来源是保守的非编码元件（CNE），它可能参与产生新的基因表达网络。Nishiharaet al.（Genome Res.2006; 16，864）在人类基因组中发现了逆转录酶（AmnSINE 1）衍生的CNE，并表明AmnSINE 1获得了它们的功能（即，exapted）在共同的哺乳动物祖先中，并参与产生哺乳动物特异性形态。因此，研究AmnSINE 1衍生的CNE在形态发生中的功能有助于我们了解哺乳动物如何通过外适应获得其特定形态特征的分子事件，这些事件发生在大约250 Ma（百万年前）的第一个哺乳动物祖先出现时。 因为在哺乳动物基因组中有超过100个AmnSINE 1衍生的CNE基因座，AmnSINE 1的突然适应一定发生了，可能是由二叠纪-三叠纪大灭绝250 Ma引发的。 在这篇综述中，我们讨论了哺乳动物特有的字符，包括大脑，exapted后，通过参考Sasakiet al.（Proc. Natl. Acad. Sci. USA2008; 105，4220）。
With the development of molecular embryology and the coming of the post‐genomic era, the molecular mechanisms of morphological evolution have recently begun to be elucidated. Whole genome sequences of many vertebrate species have been determined, and comparative genomics has suggested that one source of biodiversity is conserved non‐coding elements (CNEs), which may be involved in generating new networks of gene expression. Nishiharaet al.(Genome Res.2006; 16, 864) discovered retroposon (AmnSINE1s)‐derived CNEs in the human genome, and suggested that the AmnSINE1s obtained their function (i.e., exapted) in a common mammalian ancestor and are involved in generating mammalian‐specific morphology. Therefore, investigation of the function of AmnSINE1‐derived CNEs in morphogenesis helps us understand the molecular events of how mammals obtained their specific morphological characters by exaptation that occurred when the first mammalian ancestor emerged about 250 Ma (million years ago). Because there are more than 100 AmnSINE1‐derived CNE loci in the mammalian genome, a burst of exaptation of AmnSINE1s must have occurred, possibly triggered by the Permian‐Triassic mass extinction 250 Ma. In this review, we discuss morphological evolution of the mammalian‐specific characters including brain that were exapted after retrotransposition of AmnSINE1s by referring to two CNE loci described by Sasakiet al.(Proc. Natl. Acad. Sci. USA2008; 105, 4220).