Porcher E, Kelly J K, Cheptou P-O, Eckert C G, Johnston M O, Kalisz S
UMR 5173 MNHN-CNRS-UPMC, Conservation des Espèces, Restauration et Suivi des Populations, Muséum national d'Histoire naturelle, Paris, France.
J Evol Biol. 2009 Apr;22(4):708-17. doi: 10.1111/j.1420-9101.2009.01705.x. Epub 2009 Feb 18.
The magnitude of inbreeding depression, a central parameter in the evolution of plant mating systems, can vary depending on environmental conditions. However, the underlying genetic mechanisms causing environmental fluctuations in inbreeding depression, and the consequences of this variation for the evolution of self-fertilization, have been little studied. Here, we consider temporal fluctuations of the selection coefficient in an explicit genetic model of inbreeding depression. We show that substantial variance in inbreeding depression can be generated at equilibrium by fluctuating selection, although the simulated variance tends to be lower than has been measured in experimental studies. Our simulations also reveal that purging of deleterious mutations does not depend on the variance in their selection coefficient. Finally, an evolutionary analysis shows that, in contrast to previous theoretical approaches, intermediate selfing rates are never evolutionarily stable when the variation in inbreeding depression is due to fluctuations in the selection coefficient on deleterious mutations.
近亲繁殖衰退的程度是植物交配系统进化中的一个核心参数，它可能会因环境条件而异。然而，导致近亲繁殖衰退出现环境波动的潜在遗传机制，以及这种变异对自花受精进化的影响，目前研究较少。在此，我们在一个明确的近亲繁殖衰退遗传模型中考虑选择系数的时间波动。我们表明，通过波动选择在平衡时可产生近亲繁殖衰退的大量方差，尽管模拟的方差往往低于实验研究中测得的方差。我们的模拟还揭示，有害突变的清除并不取决于其选择系数的方差。最后，一项进化分析表明，与先前的理论方法不同，当近亲繁殖衰退的变异是由于有害突变选择系数的波动所致时，中间自交率在进化上永远不会稳定。
