Institute of Integrative Biology, ETH Zurich, Universitätsstr.16, 8092 Zurich, Switzerland.
Evolution. 2011 Feb;65(2):501-11. doi: 10.1111/j.1558-5646.2010.01145.x. Epub 2010 Nov 5.
Because of the twofold cost of sex, genes conferring asexual reproduction are expected to spread rapidly in sexual populations. However, in reality this simple prediction is often confounded by several complications observed in natural systems. Motivated by recent findings in the Cape honey bee and in the parasitoid wasp Lysiphlebus fabarum, we explore through mathematical models the spread of a recessive, parthenogenesis inducing allele in a haplodiploid population. The focus of these models is on the intricate interactions between the mode of parthenogenesis induction through automixis and complementary sex determination (CSD) systems. These interactions may result in asexual production of diploid male offspring and the spread of the parthenogenesis-inducing allele through these males. We demonstrate that if parthenogenetic females produce a substantial proportion of male offspring, this may prevent the parthenogenesis-inducing allele from spreading. However, this effect is weakened if these diploid males are at least partially fertile. We also predict a degradation of multilocus CSD systems during the spread of parthenogenesis, following which only a single polymorphic CSD locus is maintained. Finally, based on empirical parameter estimates from L. fabarum we predict that male production in parthenogens is unlikely to prevent the eventual loss of sexual reproduction in this system.
由于性别的双重代价，预计具有无性繁殖能力的基因在有性种群中会迅速传播。然而，在现实中，这一简单的预测经常受到自然系统中观察到的几个复杂因素的干扰。受海角蜜蜂和寄生蜂 Lysiphlebus fabarum 的最新发现的启发，我们通过数学模型探索了隐性、孤雌生殖诱导等位基因在单倍二倍体种群中的传播。这些模型的重点是孤雌生殖诱导通过自动融合和互补性别决定（CSD）系统的复杂相互作用。这些相互作用可能导致二倍体雄性后代的无性产生，并通过这些雄性传播诱导孤雌生殖的等位基因。我们证明，如果孤雌生殖的雌性产生大量雄性后代，这可能会阻止诱导孤雌生殖的等位基因传播。然而，如果这些二倍体雄性至少部分有生育能力，这种效果就会减弱。我们还预测，随着孤雌生殖的传播，多基因 CSD 系统会退化，之后只维持一个单一的多态性 CSD 基因座。最后，根据来自 L. fabarum 的经验参数估计，我们预测在这个系统中，孤雌生殖中的雄性产生不太可能阻止有性生殖的最终丧失。
