Ohta T, Ina Y
National Institute of Genetics, Mishima, Japan.
J Mol Evol. 1995 Dec;41(6):717-20. doi: 10.1007/BF00173150.
Using mammalian gene sequences, the variances in the numbers of synonymous and nonsynonymous substitutions among genes were estimated together with the correlation coefficient between the two. The expected correlation coefficient can be obtained under the neutral theory using these estimated values of the variances. The expected coefficient is found to often be one-half to two-thirds of the observed value. Possible causes for the disagreement were discussed, such as correlated selective constraints on the two types of substitutions and excess doublet mutations. The variance of mutation rate and that of selective constraint were also estimated. The results show that the coefficient of variation of the former is 0.2-0.3, whereas that of the latter is 0.7-0.9.
利用哺乳动物基因序列，估算了基因间同义替换和非同义替换数量的方差以及二者之间的相关系数。根据中性理论，利用这些方差的估计值可以得到预期相关系数。结果发现，预期系数通常为观测值的二分之一到三分之二。讨论了导致这种差异的可能原因，如对这两种替换的相关选择限制和过量的双联体突变。还估算了突变率方差和选择限制方差。结果表明，前者的变异系数为0.2 - 0.3，而后者的变异系数为0.7 - 0.9。
