High similarity at three MHC loci between the baiji and finless porpoise: trans-species or convergent evolution?
High similarity at three MHC loci between the baiji and finless porpoise: trans-species or convergent evolution?
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DOI：
10.1016/j.ympev.2007.05.026
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发表时间：
2008-04
影响因子：
4.1
通讯作者：
Shixia Xu;Bingyao Chen;K. Zhou;Guang Yang
中科院分区：
文献类型：
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作者：
Shixia Xu;Bingyao Chen;K. Zhou;Guang Yang
从15只白暨豚中鉴定出2个MHC-I等位基因和6个MHC-I等位基因。在MHC-I位点检测到很少的序列变异，但在MHC-I位点检测到广泛的变异。结合已报道的DQB位点的数据，白暨豚的3个MHC基因座外显子2均与江豚有显著的相似性。特别是，在MHC-I和DQB位点上，两个物种共享的一些相同的等位基因表明，趋同进化作为一个共同的适应性解决方案，以类似的环境压力在长江。而在ZH基因座上，不仅白暨豚和江豚具有相同的等位基因，而且海豚科和海豚科的其他鲸类物种也具有相同的等位基因，表明该基因存在跨种进化。
Two DRA alleles and six MHC-I alleles were identified from a group of 15 baiji (Lipotes vexillifer), the most threatened cetacean in the world. Little sequence variation was detected at the DRA locus but extensive variation at the MHC-I locus. In combination with data at the DQB locus previously reported, three MHC loci exon 2 of the baiji all revealed striking similarity with those of the finless porpoise. Especially, some identical alleles shared by both species at the MHC-I and DQB loci suggested the convergent evolution as a consequence of common adaptive solutions to similar environmental pressures in the Yangtze River. As for DRA locus, the identity alleles were shared not only by baiji and finless porpoise but by some other cetacean species of the families Phocoenidae and Delphinidae, suggesting trans-species evolution on this gene.