EXAMINATION OF CONSTANCY OF RATE OF MOLECULAR EVOLUTION
EXAMINATION OF CONSTANCY OF RATE OF MOLECULAR EVOLUTION
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DOI：
10.1007/bf01797451
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发表时间：
1974-01-01
影响因子：
3.9
通讯作者：
FITCH, WM
中科院分区：
文献类型：
--
作者：
LANGLEY, CH;FITCH, WM
通过最大似然法研究了四种蛋白质(6和β血红蛋白、细胞色素和纤维蛋白肽A)在脊椎动物中的进化。基本假设是，最小系统距离法(Fitch，1971)揭示的核苷酸替代过程是泊松过程，每个蛋白质的时间平均值是恒定的。该方法允许同时估计所有共同祖先的相对分化时间，同时利用所有四种蛋白质的信息。它还提供了对几个具有生物学意义的假说进行统计检验的可能性。结果如下：1.在脊椎动物的整个进化过程中，核苷酸替换的总速率(所有蛋白质的总和)并不是恒定的。2.在脊椎动物的进化过程中，核苷酸替换的相对速率(蛋白质之间)不是恒定的。3.尽管核苷酸替换的速率不同，但所采用的方法提供了与古生物学数据很好地相关的相对时间的估计。4.灵长类动物内的总的核苷酸替换速率再次被发现低于哺乳动物的其他部分。
The vertebrate evolution of four proteins (6andβhemoglobins, cytochromec, and fibrinopeptide A) is examined via a maximum likelihood procedure. The fundamental hypothesis is that the process of nucleotide substitution as revealed by the minimum phyletic distance procedure (Fitch, 1971) is Poisson with a constant time average for each protein. The method allows the simultaneous estimation of the relative times of divergence of all common ancestors while utilizing the information from all four proteins. It also affords the possibility of statistically testing several biologically meaningful hypotheses. The results are the following:1.The total rate (sum of all proteins) of nucleotide substitution is not constant in time throughout the evolution of vertebrates.2.The relative rates (among proteins) of nucleotide substitution are not constant throughout vertebrate evolution.3.Despite the variation in the rates of nucleotide substitution the procedure employed provides estimates of the relative time of divergence which correlate well with paleontological dates.4.The overall rate of nucleotide substitution within the primates is again found to be less than the rest of the mammals.