Wu C I, Li W H
Proc Natl Acad Sci U S A. 1985 Mar;82(6):1741-5. doi: 10.1073/pnas.82.6.1741.
When the coding regions of 11 genes from rodents (mouse or rat) and man are compared with those from another mammalian species (usually bovine), it is found that rodents evolve significantly faster than man. The ratio of the number of nucleotide substitutions in the rodent lineage to that in the human lineage since their divergence is 2.0 for synonymous substitutions and 1.3 for nonsynonymous substitutions. Rodents also evolve faster in the 5' and 3' untranslated regions of five different mRNAs; the ratios are 2.6 and 3.1, respectively. The numbers of nucleotide substitutions between members of the beta-globin gene family that were duplicated before the man-mouse split are also higher in mouse than in man. The difference is, again, greater for synonymous substitutions than for nonsynonymous substitutions. This tendency is more consistent with the neutralist view of molecular evolution than with the selectionist view. A simple explanation for the higher rates in rodents is that rodents have shorter generation times and, thus, higher mutation rates. The implication of our findings for the study of molecular phylogeny is discussed.
当将啮齿动物（小鼠或大鼠）和人类的11个基因的编码区与另一种哺乳动物物种（通常是牛）的编码区进行比较时，发现啮齿动物的进化速度明显比人类快。自啮齿动物和人类谱系分化以来，啮齿动物谱系中同义替换的核苷酸替换数与人类谱系中的比率为2.0，非同义替换的比率为1.3。在五种不同mRNA的5'和3'非翻译区，啮齿动物的进化速度也更快；比率分别为2.6和3.1。在人类与小鼠分化之前复制的β-珠蛋白基因家族成员之间的核苷酸替换数在小鼠中也高于人类。同样，同义替换的差异比非同义替换的差异更大。这种趋势与分子进化的中性论观点比与选择论观点更一致。对啮齿动物中较高进化速率的一个简单解释是，啮齿动物的世代时间较短，因此突变率较高。我们讨论了这些发现对分子系统发育研究的意义。
