Mitochondria and male lifespan: Women outlive men. An evolutionary curiosity may explain this

Mitochondria and male lifespan: Women outlive men. An evolutionary curiosity may explain this

May 31st 2014 | From the print edition

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.

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.

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.

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.

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.

 

About bambooinnovator
Kee Koon Boon (“KB”) is the co-founder and director of HERO Investment Management which provides specialized fund management and investment advisory services to the ARCHEA Asia HERO Innovators Fund (www.heroinnovator.com), the only Asian SMID-cap tech-focused fund in the industry. KB is an internationally featured investor rooted in the principles of value investing for over a decade as a fund manager and analyst in the Asian capital markets who started his career at a boutique hedge fund in Singapore where he was with the firm since 2002 and was also part of the core investment committee in significantly outperforming the index in the 10-year-plus-old flagship Asian fund. He was also the portfolio manager for Asia-Pacific equities at Korea’s largest mutual fund company. Prior to setting up the H.E.R.O. Innovators Fund, KB was the Chief Investment Officer & CEO of a Singapore Registered Fund Management Company (RFMC) where he is responsible for listed Asian equity investments. KB had taught accounting at the Singapore Management University (SMU) as a faculty member and also pioneered the 15-week course on Accounting Fraud in Asia as an official module at SMU. KB remains grateful and honored to be invited by Singapore’s financial regulator Monetary Authority of Singapore (MAS) to present to their top management team about implementing a world’s first fact-based forward-looking fraud detection framework to bring about benefits for the capital markets in Singapore and for the public and investment community. KB also served the community in sharing his insights in writing articles about value investing and corporate governance in the media that include Business Times, Straits Times, Jakarta Post, Manual of Ideas, Investopedia, TedXWallStreet. He had also presented in top investment, banking and finance conferences in America, Italy, Sydney, Cape Town, HK, China. He has trained CEOs, entrepreneurs, CFOs, management executives in business strategy & business model innovation in Singapore, HK and China.

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