Takahasi K Ryo
Population and Quantitative Genomics Team, Genomic Sciences Center, RIKEN, Yokohama 230-0045, Japan.
Genetics. 2007 May;176(1):501-11. doi: 10.1534/genetics.106.063636. Epub 2007 Apr 3.
The interplay between population subdivision and epistasis is investigated by studying the fixation probability of a coadapted haplotype in a subdivided population. Analytical and simulation models are developed to study the evolutionary fate of two conditionally neutral mutations that interact epistatically to enhance fitness. We find that the fixation probability of a coadapted haplotype shows a marked increase when the population is genetically subdivided and subpopulations are loosely connected by migration. Moderate migration and isolation allow the propagation of the mutant alleles across subpopulations, while at the same time preserving the favorable allelic combination established within each subpopulation. Together they create the condition most favorable for the ultimate fixation of the coadapted haplotype. On the basis of the analytical and simulation results, we discuss the fundamental role of population subdivision and restricted gene flow in promoting the evolution of functionally integrated systems, with some implications for the shifting-balance theory of evolution.
通过研究细分种群中一个协同适应单倍型的固定概率,来探究种群细分与上位性之间的相互作用。构建了分析模型和模拟模型,以研究两个发生上位性相互作用以提高适合度的条件中性突变的进化命运。我们发现,当种群发生遗传细分且亚种群通过迁移松散连接时,协同适应单倍型的固定概率显著增加。适度的迁移和隔离使得突变等位基因能够在亚种群间传播,同时又能保留每个亚种群内已建立的有利等位基因组合。它们共同创造了最有利于协同适应单倍型最终固定的条件。基于分析和模拟结果,我们讨论了种群细分和有限基因流在促进功能整合系统进化中的基本作用,并对进化的推移平衡理论产生了一些影响。