在通过迁移连接的补丁或环境中,本地自适应经常演变。在这些情况下,与局部适应基因座相关的基因组区域的有效迁移率降低。通过基于个人的双补丁系统的模拟,我们表明,这种减少的有效迁移导致条件有害突变的积累,但不是普遍的有害突变,邻近自适应基因座。当局部适应的遗传基础存在冗余时(即,基因型冗余),局部适应的多态性的周转允许清除有条件的有害突变负荷。与局部适应基因座相邻累积的突变负荷的量取决于冗余,重组率,迁移率,人口规模,选择的强度,和适应性等位基因的表型效应大小。我们的结果强调了在表型或适应度水平上解释局部适应模式时需要谨慎。因为局部适应的遗传基础可能是短暂的,进化可能会导致对非本地环境的适应不良。
AbstractLocal adaptation frequently evolves in patches or environments that are connected via migration. In these cases, genomic regions that are linked to a locally adapted locus experience reduced effective migration rates. Via individual-based simulations of a two-patch system, we show that this reduced effective migration results in the accumulation of conditionally deleterious mutations, but not universally deleterious mutations, adjacent to adaptive loci. When there is redundancy in the genetic basis of local adaptation (i.e., genotypic redundancy), turnover of locally adapted polymorphisms allows conditionally deleterious mutation load to be purged. The amount of mutational load that accumulates adjacent to locally adapted loci is dependent on redundancy, recombination rate, migration rate, population size, strength of selection, and the phenotypic effect size of adaptive alleles. Our results highlight the need to be cautious when interpreting patterns of local adaptation at the level of phenotype or fitness, as the genetic basis of local adaptation can be transient, and evolution may confer a degree of maladaptation to nonlocal environments.