Debating Disposable Soma and Gender Longevity Differences

A response to recent arguments on the biological basis for women's longevity advantage: "The most influential line of reasoning in gerontology is known as Disposable Soma Theory (DST). In brief, the theory states that aging is caused by accumulation of random damage, which is counteracted by repair. Repair is costly and the organism allocates exactly the needed amount of energetic resources. Recently, DST was applied to explain why women live longer than men. Women are less disposable than men, so they need a better repair and thus live longer. It might seem slightly repetitive that women live longer because they are less disposable because females need better health for reproduction. I will discuss that this explanation is also erroneous. But to start with, the name of the theory (disposable soma) is ambiguous because soma is disposable by definition: soma versus germ line. All theories of aging are more or less disposable soma theories. ... The question is why is soma disposable and what makes it disposable. According to DST, it is allocation of resources from repair to other needs. Here we will discuss drastically different cause. ... So why do women live longer? ... In brief, high accidental death rate is associated with faster aging in different species, from worms to mammals. The same is applicable to longevity of males versus females. The accidental death rate, from accidents, violence, combat, is higher in young men than in women. Historically, it was much higher. Higher accidental death rate in young men may have led them to be larger and stronger than women. ... mTOR drives cellular size growth and muscle hypertrophy, including testosterone-induced hypertrophy ... I suggest that hyper-active mTOR contributes to physical robustness of young males, allowing them to fight and compete. But hyper-active mTOR is beneficial earlier in life at the cost of accelerated aging. ... In other words, accelerated aging in males relative to females could be a byproduct of physical robustness to prevent death from extrinsic causes." As you can see there is still plenty of room for debate in even apparently simple, straightforward questions in aging science.



I have never really gotten what was unique or insightful about Disposable Soma Theroy, like you wrote... all aging theroys are disposable soma theroys, but they don't answer the question of why the soma is disposable.

FYI, The Jan. 2011 issue of Scientific American is centered around aging theroys. I have not read it yet. SA did a pretty go group of articles on Autophagy in an issue a couple of years ago.

Posted by: JohnD at December 21st, 2011 2:08 PM

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