分子進化の集団遺伝学 : 変動環境下での定常進化

抄録

Population genetics theory of molecular evolution under a fluctuating environment was reviewed. Taking the Parity Model (a two allele model under a two state Markov environment) as a prototype model, a comprehensive picture of the stationary evolution under a joint effect of mutation, stochastic selection and random genetic drift due to a finite population size was studied both on the evolution rate and the genetic polymorphism. Besides the neutral mutaion model and the slightly deleterious model as its special cases, this model has a fluctuating evolution case where the evolution rate is approximated by the environment fluctuation rate. General formulas of evolution rate were given for the weak mutation limit and the infinitely large population case. Formula of the index of dispersion of substitution numbers was given for arbitrary jump Markov process model of wild type adaptive state. Power series solution method was developed to calculate the stationary distribution of the replicon frequency for the Parity Model.