Gemmell Neil J, Metcalf Victoria J, Allendorf Fred W
School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
Trends Ecol Evol. 2004 May;19(5):238-44. doi: 10.1016/j.tree.2004.02.002.
The mitochondrial genome is considered generally to be an innocent bystander in adaptive evolution; however, there is increasing evidence that mitochondrial DNA (mtDNA) is an important contributor to viability and fecundity. Some of this evidence is now well documented, with mtDNA mutations having been shown to play a causal role in degenerative diseases, ageing, and cancer. However, most research on mtDNA has ignored the possibility that other instances exist where mtDNA mutations could have profound fitness consequences. Recent work in humans and other species now indicates that mtDNA mutations play an important role in sperm function, male fertility, and male fitness. Ironically, deleterious mtDNA mutations that affect only males, such as those that impair sperm function, will not be subject to natural selection because mitochondria are generally maternally inherited and could reach high frequencies in populations if the mutations are not disadvantageous in females. Here, we review how such mtDNA mutations might affect the viability of natural populations. We consider factors that increase or decrease the strength of the effect of mtDNA mutations on population viability and discuss what mechanisms exist to mitigate deleterious mtDNA effects.
线粒体基因组通常被认为是适应性进化中的无辜旁观者；然而，越来越多的证据表明线粒体DNA（mtDNA）对生存能力和繁殖力有重要贡献。其中一些证据现在已有充分记录，mtDNA突变已被证明在退行性疾病、衰老和癌症中起因果作用。然而，大多数关于mtDNA的研究忽略了其他存在mtDNA突变可能产生深远适应性后果的情况。人类和其他物种的最新研究表明，mtDNA突变在精子功能、男性生育能力和男性适应性中起重要作用。具有讽刺意味的是，仅影响男性的有害mtDNA突变，如那些损害精子功能的突变，不会受到自然选择的影响，因为线粒体通常是母系遗传的，如果这些突变对女性没有不利影响，它们可能在种群中达到高频率。在这里，我们回顾了此类mtDNA突变可能如何影响自然种群的生存能力。我们考虑了增加或降低mtDNA突变对种群生存能力影响强度的因素，并讨论了存在哪些机制来减轻有害mtDNA的影响。
