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Mitochondria and male lifespan
粒腺體影響男性壽命
Power down
粒腺體阻斷
Women outlive men. An evolutionary curiosity may explain this
女性比男性壽命長久。欲知為何，請看進化學分解
Mankiller?
男性健康殺手？
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.
過去，人們認為女性比男性弱，而這對于客觀地調查過此現(xiàn)象的人來說是個迷，因為女性比男性壽命長，很多國家或地區(qū)都是如此。在一定程度上，這可能是因為男性要狂暴一些，而且他們的狂暴是針對其他男性。但也有可能是受生理影響。男性精力耗損要比女性快。個中緣由還沒有人知道。
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.
瑪?shù)铝铡け瓤寺前拇罄麃喯つ岽髮W工作者，她跟同事一起提出一種假說。他們在皇家學會哲學學報發(fā)表的一篇論文中指出，男性壽命比女性短的原因可能取決于亞細胞結構，也就是粒腺體。粒腺體通過燃燒葡萄糖為機體提供能量，利用該能量釋放三磷腺苷，三磷腺苷是整個機體的燃料。
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.
粒腺體很有趣。他們是細菌與十億年前的動物或植物祖先的衍生物。如此便保留住了基因。這就是問題的開始。從遺傳學角度講，為了避免同一個細胞內不同的粒腺體相互排斥，大多數(shù)生物都會選擇系屬同一個細胞的線粒體，通常是同一個雌細胞。如比克曼博士所提到的一樣，雄性線粒體陷入進化死胡同。雄性線粒體不能逐漸形成雄性專一方式，因為雄性線粒體在雄性生物體上棲息的多么好，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. 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.
這和女性和男性生生理機能十分相似，但又不是中心問題。比克曼博士認為，這可能關系到margin。她仔細觀察了一種名為利伯氏視神經病變的疾病，是有缺陷的粒腺體基因引起的。女性的發(fā)病率只有10%，女性細胞還包括受損細胞。而男性發(fā)病率高達50%，主要是粒腺體堵塞引起的 。比克曼博士又列舉出了其他疾病，這比利伯氏視神經病變要常見的多（例如心肌病、糖尿病和其他耳聾癥），這些疾病有時或經常含有粒腺體成分。男性患此類疾病的發(fā)病率比女性高，男性患者也比女性患者病情嚴重的多。此篇論文的研究程度所達程度并不是如此，而且這類問題早已有人考慮過。
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.
關于這些研究缺乏信息可能是因為沒有幾個醫(yī)生研究這類問題，比如進化生物學，他們也無法提出合適的問題。比克曼教授的假說也許是錯誤的，但是，這種假說看起來很有道理，有研究價值。譯者：毛秀云
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