Fish of the superfamily Cobitoidea sensu stricto （namely Ioaches） exhibit extremely high diversity of color patterns, but so far little is known about their evolutionary mechanism. Melanocortin 1 receptor gene （MCI...Fish of the superfamily Cobitoidea sensu stricto （namely Ioaches） exhibit extremely high diversity of color patterns, but so far little is known about their evolutionary mechanism. Melanocortin 1 receptor gene （MCIR） plays an important role during the synthesis of melanin and formation of animal body color patterns. In this study, we amplified and sequenced the partial MCIR gene for 44 loach individuals representing 31 species of four families. Phylogenetic analyses yielded a topology congruent with previous studies using multiple nuclear loci, showing that each of the four families was monophyletic with sister relationships of Botiidae＋ （Cobitidae＋（Balitoridae＋Nemacheilidae））. Gene evolutionary analyses indicated that MCIR in Ioaches was under purifying selection pressure, with various sites having different dNIds values. Both Botiidae and Cobitidae had lower dN/ds values than those of background lineages, suggesting their evolution might be strongly affected by purifying selection pressure. For Balitoddae and Nemacheilidae, both had larger dNIds values than those of background lineages, suggesting they had a faster evolutionary rate under more relaxed selection pressure. Consequently, we inferred that the relatively stable color patterns in Botiidae and Cobitidae might result from the strong purifying selection pressure on the MC1R gene, whereas the complicated and diverse color patterns in Balitoridae and Nemacheilidae might be associated with the relaxed selection pressure. Given the easy experimental procedure for the partial MCTR gene and its excellent performance in reconstructing phylogeny, we suggest this gene could be used as a good molecular marker for the phylogenetic study of fish species.展开更多
黑色素皮质激素受体1基因(Melanocortin receptor 1,Mc1r)作为控制动物毛色的主效候选基因,在动物的毛色中发挥了重要作用。以10个地理种群112只中缅树鼩为研究对象,采用PCR扩增测序共获得954 bp mc1r序列。结果显示:1)954 bp mc1r序列...黑色素皮质激素受体1基因(Melanocortin receptor 1,Mc1r)作为控制动物毛色的主效候选基因,在动物的毛色中发挥了重要作用。以10个地理种群112只中缅树鼩为研究对象,采用PCR扩增测序共获得954 bp mc1r序列。结果显示:1)954 bp mc1r序列共编码317个氨基酸,蛋白质二级结构以α-螺旋为主,并含有7个跨膜结构域。2)mc1r构建的系统进化树结果显示,10个地理种群中缅树鼩聚为4支,海南种群一支、大新种群一支、片马种群一支、其他种群一支。结果说明,不同地理种群中缅树鼩生存环境的差异导致了毛色的差异。展开更多
基金supported by the National Natural Science Foundation of China(NSFC 31272306,31400359,31401968)
文摘Fish of the superfamily Cobitoidea sensu stricto （namely Ioaches） exhibit extremely high diversity of color patterns, but so far little is known about their evolutionary mechanism. Melanocortin 1 receptor gene （MCIR） plays an important role during the synthesis of melanin and formation of animal body color patterns. In this study, we amplified and sequenced the partial MCIR gene for 44 loach individuals representing 31 species of four families. Phylogenetic analyses yielded a topology congruent with previous studies using multiple nuclear loci, showing that each of the four families was monophyletic with sister relationships of Botiidae＋ （Cobitidae＋（Balitoridae＋Nemacheilidae））. Gene evolutionary analyses indicated that MCIR in Ioaches was under purifying selection pressure, with various sites having different dNIds values. Both Botiidae and Cobitidae had lower dN/ds values than those of background lineages, suggesting their evolution might be strongly affected by purifying selection pressure. For Balitoddae and Nemacheilidae, both had larger dNIds values than those of background lineages, suggesting they had a faster evolutionary rate under more relaxed selection pressure. Consequently, we inferred that the relatively stable color patterns in Botiidae and Cobitidae might result from the strong purifying selection pressure on the MC1R gene, whereas the complicated and diverse color patterns in Balitoridae and Nemacheilidae might be associated with the relaxed selection pressure. Given the easy experimental procedure for the partial MCTR gene and its excellent performance in reconstructing phylogeny, we suggest this gene could be used as a good molecular marker for the phylogenetic study of fish species.
文摘黑色素皮质激素受体1基因(Melanocortin receptor 1,Mc1r)作为控制动物毛色的主效候选基因,在动物的毛色中发挥了重要作用。以10个地理种群112只中缅树鼩为研究对象,采用PCR扩增测序共获得954 bp mc1r序列。结果显示:1)954 bp mc1r序列共编码317个氨基酸,蛋白质二级结构以α-螺旋为主,并含有7个跨膜结构域。2)mc1r构建的系统进化树结果显示,10个地理种群中缅树鼩聚为4支,海南种群一支、大新种群一支、片马种群一支、其他种群一支。结果说明,不同地理种群中缅树鼩生存环境的差异导致了毛色的差异。
基金Supported by Key Project of Science and Technology of Shanxi Province(No.20140311019-3)Doctoral research Project of Shanxi Agricultural University(No.XB2009022)~~
