医学考博英语阅读 | 线粒体影响男性寿命

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Mitochondria and male lifespan

线粒体影响男性寿命

Power down

线粒体阻断

Women outlive men. An evolutionary curiosity may explain this Mankiller.

女性比男性寿命长久。欲知为何，请看进化学分解

WHY past generations regarded women as the weaker sex is a mystery to anyone who has examined the question objectively, for they are far stronger than men—outliving them in pretty well every society in the world. Partly that is because men are more violent, and their violence is largely directed at other men. But partly it is physiological. Men seem to wear out faster than women do. Yet no one knows why.

过去，人们认为女性比男性弱，而这对于客观地调查过这个现象的人们来说是个迷，因为女性比男性寿命长，很多国家或地区都是如此。在一定程度上，这可能是因为男性要野蛮一些，而且他们的野蛮是针对其他男性。但也有可能是受生理影响。男性精力耗损要比女性快，个中缘由还不得而知。

mitochondria

Madeleine Beekman of the University of Sydney, Australia, and her colleagues, however, have a hypothesis. As they outline in a paper in the Philosophical Transactions of the Royal Society, they think at least some of the blame lies with subcellular structures called mitochondria (pictured), which provide the body with its power by burning glucose and using the energy thus released to make ATP, a molecule that is biology’s universal fuel.

玛德琳 · 比克曼是澳大利亚悉尼大学工作者，她跟同事一起提出了一个假说。他们在皇家学会哲学学报发表的一篇论文中指出，男性寿命比女性短的原因可能取决于亚细胞结构，也就是线粒体。线粒体通过燃烧葡萄糖为机体提供能量，利用该能量释放三磷腺苷，三磷腺苷是整个机体的燃料。

Mitochondria are intriguing. They are descendants of bacteria that teamed up with the ancestors of animal and plant cells about a billion years ago. As such, they retain their own genes. And this is where the problems start. To avoid fights between genetically different mitochondria in the same cell, most species have arranged for their mitochondria to come from only one parent—usually the mother. This means, as Dr Beekman notes, that a male’s mitochondria are stuck in an evolutionary dead end. They cannot evolve in male-specific ways, because no matter how much good they do a male body they inhabit, they will not be passed on to the next generation.

线粒体很有趣。他们是细菌与十亿年前的动物或植物祖先的衍生物。如此便保留住了基因。这就是问题的开始。从遗传学角度讲，为了避免同一个细胞内不同的线粒体相互排斥，大多数生物都会选择系属同一个细胞的线粒体，通常是同一个雌细胞。如比克曼博士所提到的一样，雄性线粒体陷入进化死胡同。雄性线粒体不能逐渐形成雄性专一方式，因为雄性线粒体在雄性生物体上栖息的多么好，都不能繁衍到下一代。

Male and female physiologies are sufficiently similar for this not to be a central problem, but Dr Beekman thinks it may matter at the margins. She observes that one disease, called Leber’s hereditary optic neuropathy, which is caused by a faulty mitochondrial gene, occurs in only 10% of women whose cellular power-packs include the damaged gene, but in 50% of men whose mitochondria are so encumbered. The gene in question, in other words, is less likely to harm a woman than a man.

这和女性和男性生生理机能十分相似，但又不是核心问题，比克曼博士认为它对于一些边缘问题有影响。她仔细观察了一种名为利伯氏视神经病变的疾病，是有缺陷的线粒体基因引起的。女性的发病率只有10%，女性细胞还包括受损细胞。而男性发病率高达 50%，主要是线粒体堵塞引起的 。

She then lists a lot of other diseases, including ones far commoner than Leber’s hereditary optic neuropathy (such as cardiomyopathy, diabetes and several forms of deafness) that sometimes or always have a mitochondrial component, and speculates that some of these, too, may prove to be either more common or more serious in men than in women. As far as her searches of the literature can show, this is not something that has yet been looked into.

比克曼博士又列举出了其他疾病，这比利伯氏视神经病变要常见的多（例如心肌病、糖尿病和其他耳聋症），这些疾病有时或经常含有线粒体成分。男性患此类疾病的发病率比女性高，男性患者也比女性患者病情严重的多。此篇论文的研究程度所达程度并不是如此，而且这类问题早已有人考虑过。

Part of the reason for this absence of information may be that few doctors think like evolutionary biologists, so they fail to ask the appropriate questions. Dr Beekman’s hypothesis may turn out to be wrong. But it sounds eminently plausible, and certainly worth investigating.

关于这些研究缺乏信息可能是因为很少有医生研究这类问题，比如进化生物学，他们也无法提出合适的问题。比克曼教授的假说也许是错误的，但是，这种假说看起来很有道理，而且有研究价值。