Wiener Pamela, Feldman Marcus W, Otto Sarah P
Department of Biological Sciences, Stanford University, Stanford, CA, 94305, USA.
Evolution. 1992 Jun;46(3):775-782. doi: 10.1111/j.1558-5646.1992.tb02083.x.
It has recently been argued that because the genetic load borne by an asexual species resulting from segregation, relative to a comparable sexual population, is greater than two, sex can overcome its twofold disadvantage and succeed. We evaluate some of the assumptions underlying this argument and discuss alternative assumptions. Further, we simulate the dynamics of competition between sexual and asexual types. We find that for populations of size 100 and 500 the advantages of segregation do not outweigh the cost of producing males. We conclude that, at least for small populations, drift and the cost of sex govern the evolution of sexuality, not selection or segregation. We believe, however, that if sexual and asexual populations were isolated for a sufficiently long period, segregation might impart a fitness advantage upon sexuals that could compensate for the cost of sex and allow sexuals to outcompete asexuals upon their reunion.
最近有人认为，由于与可比的有性种群相比，无性物种因分离而承受的遗传负荷大于两倍，有性生殖可以克服其两倍的劣势并取得成功。我们评估了这一论点背后的一些假设，并讨论了替代假设。此外，我们模拟了有性和无性类型之间的竞争动态。我们发现，对于规模为100和500的种群，分离的优势并不超过产生雄性的成本。我们得出结论，至少对于小种群来说，遗传漂变和有性生殖的成本决定了有性生殖的进化，而不是选择或分离。然而，我们认为，如果有性和无性种群被隔离足够长的时间，分离可能会赋予有性生殖者一种适应性优势，这种优势可以补偿有性生殖的成本，并使有性生殖者在重新团聚时胜过无性生殖者。
