Does diploidy increase the rate of adaptation?
Does diploidy increase the rate of adaptation?
复制标题
二倍体会增加适应率吗？
DOI：
10.1093/genetics/136.4.1475
复制
发表时间：
1994
期刊：
影响因子：
3.3
通讯作者：
Otto,SP
中科院分区：
文献类型：
--
作者：
Orr,HA;Otto,SP
对二倍体进化的解释主要集中在掩盖有害等位基因所获得的优势上。然而，最近的理论表明，掩蔽并不总是为二倍体提供优势，并且永远不会有利于主要无性生物中的二倍体。我们探索了一种被忽视的替代理论，该理论认为，通过使基因组大小加倍，二倍体使有利突变出现的速度加倍。因此，二倍体的适应速度被认为比单倍体更快。然而，适应率不仅取决于新的有利突变的出现率，还取决于这些突变的整合率（这取决于种群规模和有利突变的优势）。我们发现，无论是无性动物还是有性动物，通过二倍体使突变率加倍通常不会加快适应速度。事实上，在许多条件下，二倍体会减慢适应速度。
Explanations of the evolution of diploidy have focused on the advantages gained from masking deleterious alleles. Recent theory has shown, however, that masking does not always provide an advantage to diploidy and would never favor diploidy in predominantly asexual organisms. We explore a neglected alternative theory which posits that, by doubling the genome size, diploids double the rate at which favorable mutations arise. Consequently, the rate of adaptation in diploids is presumed to be faster than in haploids. The rate of adaptation, however, depends not only on the rate of appearance of new favorable mutations but also on the rate at which these mutations are incorporated (which depends on the population size and on the dominance of favorable mutations). We show that, in both asexuals and sexuals, doubling the mutation rate via diploidy often does not accelerate the rate of adaptation. Indeed, under many conditions, diploidy slows adaptation.