Proceedings of the National Academy of Sciences of the United States of America ( IF 9.412 ) Pub Date : 2021-05-11 , DOI: 10.1073/pnas.2022805118 Denis Roze
One of the most widely cited hypotheses to explain the evolutionary maintenance of genetic recombination states that the reshuffling of genotypes at meiosis increases the efficiency of natural selection by reducing interference among selected loci. However, and despite several decades of theoretical work, a quantitative estimation of the possible selective advantage of a mutant allele increasing chromosomal map length (the average number of cross-overs at meiosis) remains difficult. This article derives a simple expression for the strength of selection acting on a modifier gene affecting the genetic map length of a whole chromosome or genome undergoing recurrent mutation. In particular, it shows that indirect selection for recombination caused by interference among mutations is proportional to , where is the effective population size, U is the deleterious mutation rate per chromosome, and R is the chromosome map length. Indirect selection is relatively insensitive to the fitness effects of deleterious alleles, epistasis, or the genetic architecture of recombination rate variation and may compensate for substantial costs associated with recombination when linkage is tight. However, its effect generally stays weak in large, highly recombining populations.
解释基因重组的进化维持的最广泛引用的假设之一指出，减数分裂时基因型的改组通过减少选定基因座之间的干扰而提高了自然选择的效率。然而，尽管进行了数十年的理论研究，但仍难以对突变等位基因增加染色体图谱长度（减数分裂时的平均交换次数）的可能选择优势进行定量估计。本文得出一个简单的表达式，表明选择强度作用于修饰子基因上，该修饰子基因影响经历反复突变的整个染色体或基因组的遗传图谱长度。特别是，它表明由突变之间的干扰引起的重组的间接选择与， 在哪里 是有效种群大小，U是每条染色体的有害突变率，R是染色体图长度。间接选择对有害等位基因的适应性效应，上位性或重组率变异的遗传结构相对不敏感，当连锁紧密时，可能会补偿与重组相关的大量成本。但是，在大量高度重组的人群中，其效果通常仍然很弱。