Keightley P D, Hill W G
Institute of Cell, Animal and Population Biology, University of Edinburgh, Scotland.
Genetics. 1992 Jul;131(3):693-700. doi: 10.1093/genetics/131.3.693.
To measure the amount of new genetic variation in 6-week weight of mice arising each generation from mutation, selection lines derived from an initially inbred strain were maintained for 25 generations. An analysis using an animal model with restricted maximum likelihood was applied to estimate a mutational genetic component of variance for the infinitesimal model of many genes of small effect. Assuming that the inbred base population was at a mutation-drift equilibrium, it is estimated that the heritability for body size has increased by 1.0% per generation, with lower and upper confidence limits of 0.6% and 1.6%, respectively. A model which includes a mutational genetic component of variance fits the data much better than one involving only base population genetic variance. A model with no genetic component fits the data very poorly. An environmental covariance of body size of mother and offspring was included in the model and accounts for 10% of the variance. By using information only from the observed response to selection, the estimated increase in heritability from mutation is 0.3% per generation. These values are higher than published estimates for the increase in variance from spontaneous mutations in bristle traits of Drosophila, for which there are extensive data, but similar to estimates for various skeletal traits in mice.
为了测量每一代小鼠因突变产生的6周龄体重新遗传变异量，我们从一个最初的近交系中维持了25代选择品系。采用限制最大似然法的动物模型分析来估计许多小效应基因的无穷小模型的突变遗传方差成分。假设近交基础群体处于突变-漂变平衡状态，估计体型的遗传力每代增加1.0%，置信下限和上限分别为0.6%和1.6%。一个包含突变遗传方差成分的模型比仅涉及基础群体遗传方差的模型能更好地拟合数据。一个没有遗传成分的模型对数据的拟合非常差。模型中包含了母体和后代体型的环境协方差，其占方差的10%。仅利用观察到的选择反应信息，估计突变导致的遗传力每代增加0.3%。这些值高于已发表的关于果蝇刚毛性状自发突变导致的方差增加的估计值（果蝇有大量相关数据），但与小鼠各种骨骼性状的估计值相似。
