Curr Biol：女性寿命比男性长或与线粒体DNA突变有关

科学家们正在开始理解生命中永远的未解之谜之一：为什么女性的平均寿命要比男性长？根据2012年8月2日在线发表在Current Biology期刊上的一项研究，研究人员描述了线粒体DNA上的突变如何能够解释男性和女性预期寿命之间的差别。

来自澳大利亚莫纳什大学生物科学学院的D amian Dowling博士和博士生Florencia Camus与来自英国兰卡斯特大学的David Clancy博士合作而揭示出雄性和雌性果蝇在寿命和生物衰老之间的差别，其中这些果蝇携带者不同起源的线粒体。他们发现线粒体上的遗传变异是预测雄性果蝇而不是雌性果蝇的可靠预测因子。

这些结果表明线粒体DNA上的多种突变影响雄性能够活多长以及它们的衰老速度。Dowling博士说，“所有动物都含有线粒体，而且雌性比雄性寿命长的倾向在很多种物种当中比较常见。因此，我们的结果提示着我们发现的线粒体突变总体上能够导致整个动物王国中雄性更快衰老。”

研究人员说，这些突变能够全部归因于线粒体基因从亲代传递到子代是存在的显著差别。尽管子代接受来自父代和母代的大多数基因，但是它们只接受来自母代的线粒体基因。这意味着被称作自然选择的进化质量控制过程只筛选母代线粒体基因的质量。

如果发生的线粒体突变伤害父代，但是对母代没有影响，那么这种突变悄悄地躲过自然选择的筛查。经过一千多代后，很多这样的突变在只在雄性体内积累，而雌性丝毫不受这些突变的影响。

这项研究表明线粒体是影响男性健康的突变热点。如今，研究人员想要研究雄性体内的遗传基因可能保护它们自己来抵消这些有害突变的影响，从而保持健康。

本文编译自Why women outlive men: It's in our genes, study says

doi: 10.1016/j.cub.2012.07.018
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Mitochondria, Maternal Inheritance, and Male Aging

M. Florencia Camus, David J. Clancy, Damian K. Dowling

The maternal transmission of mitochondrial genomes invokes a sex-specific selective sieve, whereby mutations in mitochondrial DNA can only respond to selection acting directly on females [1,2,3]. In theory, this enables male-harming mutations to accumulate in mitochondrial genomes when these same mutations are neutral, beneficial, or only slightly deleterious in their effects on females [1,2,3]. Ultimately, this evolutionary process could result in the evolution of male-specific mitochondrial mutation loads; an idea previously termed Mother’s Curse [2,4,5,6]. Here, we present evidence that the effects of this process are broader than hitherto realized, and that it has resulted in mutation loads affecting patterns of aging in male, but not female Drosophila melanogaster. Furthermore, our results indicate that the mitochondrial mutation loads affecting male aging generally comprise numerous mutations over multiple sites. Our findings thus suggest that males are subject to dramatic consequences that result from the maternal transmission of mitochondrial genomes. They implicate the diminutive mitochondrial genome as a hotspot for mutations that affect sex-specific patterns of aging, thus promoting the idea that a sex-specific selective sieve in mitochondrial genome evolution is a contributing factor to sexual dimorphism in aging, commonly observed across species [7,8,9].