Department of Environmental Changes, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan.
Department of Contemporary Social Studies, Chikushi Jogakuen University, Dazaifu, Japan.
J Theor Biol. 2019 Apr 21;467:134-141. doi: 10.1016/j.jtbi.2019.02.001. Epub 2019 Feb 6.
Gene duplication is one of the major mechanisms of molecular evolution. Gene duplication enables copies of a gene to accumulate mutations through functional redundancy. If a gene encodes a specific protein that interacts with other proteins, RNA, or DNA, the relaxation of selective constraints caused by gene duplication might contribute to the fixation of compensatory mutations that occur at the interacting sites. In this study, we investigate the effect of gene duplication, epistasis among the duplicated copies and gene conversion on the fixation time of compensatory mutations by extending the original model of compensatory evolution proposed by Kimura in 1985. Our simulation results reveal that the time to fixation of compensatory mutations can be decreased remarkably by gene duplication if one of the duplicated loci can completely mask the deleterious effects of a mutation that occurs at the other locus. Conversely, the fixation time can be increased by gene duplication if such functional compensation is weak. We also show that the combination of the degree of functional compensation and the rate of gene conversion between duplicate loci have contrasting effects on the time to fixation of compensatory mutations.
基因复制是分子进化的主要机制之一。基因复制使基因的副本能够通过功能冗余积累突变。如果一个基因编码一种与其他蛋白质、RNA 或 DNA 相互作用的特定蛋白质，那么基因复制引起的选择压力放松可能有助于在相互作用位点发生的补偿性突变的固定。在这项研究中，我们通过扩展 Kimura 在 1985 年提出的补偿性进化的原始模型，研究了基因复制、复制副本之间的上位性和基因转换对补偿性突变固定时间的影响。我们的模拟结果表明，如果复制的一个位点可以完全掩盖另一位点发生的突变的有害影响，那么基因复制可以显著降低补偿性突变的固定时间。相反，如果这种功能补偿较弱，则复制的固定时间可能会增加。我们还表明，功能补偿的程度和重复位点之间的基因转换率的组合对补偿性突变固定时间具有相反的影响。
