The Population Genetics of Evolutionary Rescue in Diploids: X Chromosomal versus Autosomal Rescue.
The Population Genetics of Evolutionary Rescue in Diploids: X Chromosomal versus Autosomal Rescue.
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二倍体进化拯救的群体遗传学：X 染色体与常染色体拯救。
DOI：
10.1086/707139
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Orr,HAllen
中科院分区：
文献类型：
--
作者：
Unckless,RobertL;Orr,HAllen
大多数种群遗传理论假设种群适应环境变化而不改变种群规模。然而，环境变化可能如此严重，以至于种群规模下降，如果没有适应，就会灭绝。这种“进化拯救”的情景与传统的适应模式不同，因为拯救涉及适应与灭绝之间的竞赛。虽然大多数以前的工作通常集中在单倍体的进化拯救模型，在这里，我们考虑二倍体。在许多物种中，二倍体为适应引入了一个新的特征：适应性进化可能发生在性染色体或常染色体上。先前的非拯救适应研究表明，X染色体与常染色体上的相对适应率取决于有益突变的优势，反映了有效群体大小和选择效力的差异。在这里，我们将这些结果扩展到进化救援，并发现，给定相等大小的染色体，有更大的参数空间，其中X更有可能有助于适应比常染色体相对于标准nonrescue模型。我们还讨论了如何微妙的影响，显性可以增加二倍体的进化救援的机会时，绝对杂合体健身接近1。这些影响在标准非救援模型中不会出现。
Most population genetic theory assumes that populations adapt to an environmental change without a change in population size. However, environmental changes might be so severe that populations decline in size and, without adaptation, become extinct. This “evolutionary rescue” scenario differs from traditional models of adaptation in that rescue involves a race between adaptation and extinction. While most previous work has usually focused on models of evolutionary rescue in haploids, here we consider diploids. In many species, diploidy introduces a novel feature into adaptation: adaptive evolution might occur either on sex chromosomes or on autosomes. Previous studies of nonrescue adaptation revealed that the relative rates of adaptation on the X chromosome versus autosomes depend on the dominance of beneficial mutations, reflecting differences in effective population size and the efficacy of selection. Here, we extend these results to evolutionary rescue and find that, given equal-sized chromosomes, there is greater parameter space in which the X is more likely to contribute to adaptation than the autosomes relative to standard nonrescue models. We also discuss how subtle effects of dominance can increase the chance of evolutionary rescue in diploids when absolute heterozygote fitness is close to 1. These effects do not arise in standard nonrescue models.