Muirhead Christina A, Lande Russell
Department of Biology, University of Oregon, Eugene, Oregon, 97403-1210.
Evolution. 1997 Oct;51(5):1409-1415. doi: 10.1111/j.1558-5646.1997.tb01464.x.
Partial asexual reproduction was introduced into a model of inbreeding depression due to nearly recessive lethal mutations in a partially selfing population. The frequencies of asexuality, selfing, and outcrossing were either constant or occurred in cycles of a single sexual generation followed by one or more asexual generations. We found that increasing the degree of asexuality generally increases the inbreeding depression maintained in an equilibrium population with a given selfing rate. This is due to the increase in the number of mutations relative to sexual generations during which selfing-induced purging of mutations may take place. For very high genomic mutation rates, sufficient to produce a threshold rate of self-fertilization for purging recessive lethal mutations, asexuality can have the opposite effect, decreasing equilibrium inbreeding depression, because of an increase in the efficiency of selection against mutations in heterozygotes with asexuality.
由于部分自交群体中存在近乎隐性的致死突变，部分无性繁殖被引入到近亲繁殖衰退模型中。无性繁殖、自交和异交的频率要么保持恒定，要么以一个有性世代接着一个或多个无性世代的周期出现。我们发现，在给定自交率的平衡群体中，增加无性繁殖程度通常会加剧近亲繁殖衰退。这是因为相对于自交诱导突变清除可能发生的有性世代，突变数量增加了。对于非常高的基因组突变率，足以产生清除隐性致死突变的自交阈值率，无性繁殖可能会产生相反的效果，降低平衡近亲繁殖衰退，因为无性繁殖会提高对杂合子中突变的选择效率。
