Effects of spontaneous mutation accumulation on sex ratio traits in a parasitoid wasp
Effects of spontaneous mutation accumulation on sex ratio traits in a parasitoid wasp
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DOI：
10.1111/j.1558-5646.2008.00434.x
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发表时间：
2008-08-01
期刊：
影响因子：
3.3
通讯作者：
West, Stuart A.
中科院分区：
文献类型：
--
作者：
Pannebakker, Bart A.;Halligan, Daniel L.;West, Stuart A.
事实证明，性别分配理论在预测个体何时应该根据环境条件调整后代的性别方面非常成功。然而，我们对性别比的潜在遗传学或遗传结构如何限制适应性性别比行为知之甚少。我们研究了突变如何影响寄生蜂性比的遗传变异。在突变累积实验中，我们确定了性别比的可变性，并将其与在自然种群中观察到的遗传变异量进行了比较。我们发现，可变性(h(M)(2))的范围从0.001到0.002，类似于对其他生物体生活史特征的估计。这些估计表明，每5-60代人就会发生一次突变，这会使性别比增加约0.01(男性比例)。在这项研究和其他研究中，绿僵菌性别比的遗传变异在0.02到0.17(广义遗传力，H-2)之间。如果通过突变-选择平衡来维持性别比，给出我们的突变参数，预计会有更高的遗传方差。相反，观察到的遗传差异可能表明，对性别比突变的额外选择会对其他健康特征和性别比(即多效性)产生有害影响，就像人们认为的更普遍的情况一样。
Sex allocation theory has proved extremely successful at predicting when individuals should adjust the sex of their offspring in response to environmental conditions. However, we know rather little about the underlying genetics of sex ratio or how genetic architecture might constrain adaptive sex-ratio behavior. We examined how mutation influenced genetic variation in the sex ratios produced by the parasitoid wasp Nasonia vitripennis. In a mutation accumulation experiment, we determined the mutability of sex ratio, and compared this with the amount of genetic variation observed in natural populations. We found that the mutability (h(m)(2)) ranges from 0.001 to 0.002, similar to estimates for life-history traits in other organisms. These estimates suggest one mutation every 5-60 generations, which shift the sex ratio by approximately 0.01 (proportion males). in this and other studies, the genetic variation in N. vitripennis sex ratio ranged from 0.02 to 0.17 (broad-sense heritability, H-2). If sex ratio is maintained by mutation-selection balance, a higher genetic variance would be expected given our mutational parameters. Instead, the observed genetic variance perhaps suggests additional selection against sex-ratio mutations with deleterious effects on other fitness traits as well as sex ratio (i.e., pleiotropy), as has been argued to be the case more generally.