Coadaptation of mitochondrial and nuclear genes, and the cost of mother's curse
Coadaptation of mitochondrial and nuclear genes, and the cost of mother's curse
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DOI：
10.1098/rspb.2017.2257
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发表时间：
2018-01-31
影响因子：
4.7
通讯作者：
Dowling, Damian K.
中科院分区：
文献类型：
--
作者：
Connallon, Tim;Camus, M. Florencia;Dowling, Damian K.
严格的母系遗传使线粒体基因组容易积累突变，这些突变对男性有害，但对女性是良性或有益的。这种“母亲的诅咒”效应可以降低男性的生存和生育能力，如果不通过对抗进化过程。细胞核和线粒体基因组之间的相互适应--细胞核基因进化以补偿对男性有害的线粒体替代--可能最终解决母亲的诅咒。然而，在有丝分裂核共同进化过程中，男性仍然会产生短暂的适应性成本，目前还不清楚这种成本应该有多严重。我们提出了一个人口遗传分析的线粒体核共适应，以解决母亲的诅咒的影响，并表明，“男性线粒体负荷”的幅度-线粒体替代男性健身组件的负面影响-可能是大的，即使是补偿性进化的遗传变异是丰富的。我们还发现，男性的负载是令人惊讶的敏感人口规模：男性健身成本的线粒体核协同进化是特别明显的小型和大型人口，并在人口的中间规模最小化。我们的研究结果揭示了复杂的人口和遗传约束之间的相互作用，在解决母亲的诅咒，这表明潜在的广泛的物种差异的易感性母亲的诅咒的影响。
Strict maternal inheritance renders the mitochondrial genome susceptible to accumulating mutations that harm males, but are otherwise benign or beneficial for females. This 'mother's curse' effect can degrade male survival and fertility if unopposed by counteracting evolutionary processes. Coadaptation between nuclear and mitochondrial genomes-with nuclear genes evolving to compensate for male-harming mitochondrial substitutions-may ultimately resolve mother's curse. However, males are still expected to incur a transient fitness cost during mito-nuclear coevolution, and it remains unclear how severe such costs should be. We present a population genetic analysis of mito-nuclear coadaptation to resolve mother's curse effects, and show that the magnitude of the 'male mitochondrial load'-the negative impact of mitochondrial substitutions on male fitness components-may be large, even when genetic variation for compensatory evolution is abundant. We also find that the male load is surprisingly sensitive to population size: male fitness costs of mito-nuclear coevolution are particularly pronounced in both small and large populations, and minimized in populations of intermediate size. Our results reveal complex interactions between demography and genetic constraints during the resolution of mother's curse, suggesting potentially widespread species differences in susceptibility to mother's curse effects.