Why Would Late Puberty Make You Live Longer?

In a recent issue of Science, there is an article about some of the great dicoveries flowing out the UK Biobank, a huge registry of 150,000 Britons. One intriguing set of findings is the discovery that some of the Neanderthal genes that we have held onto are immune system genes, which is what we would expect if viral shockwave theory is true.

But, what I want to focus is this discovery: genes that cause early puberty are rare in people who are likely to live for a long time. Some of the findings are here and here.

The investigators were surprised by this. They wouldn’t have been, if they had subscribed to the theory of programmed aging. If aging is programmed, then all major life transitions should be accelerated in individuals who die early.

Certainly if aging is programmed to turn the population over onto the next generation, per Red King Theory, then this is exactly what you would expect: early reproduction should go hand in hand with early aging. Another study has noted that early puberty is associated with poor health. And as seen in the graph below, this relationship between age of sexual maturity and lifespan (sometimes call Gompertz’s law) seems to hold true across multiple species, with the exception of hydra, which are thought to live forever. (Edit 2/16/19, and also naked mole rats).

Age of first reproduction vs. maximum longevity minus age of first reproduction in animals. When maximum longevities were not available, average longevities were used (six cases). From Mortality Patterns Suggest Lack of Senescence in Hydra. Daniel E. Martı́nez

So this is strong evidence against deterioration theory of aging–there should be no association between puberty and aging if that were the case. It is a also reasonaby strong case against the “lack of evolutionary pressure” theory. There should be a relationship between end of reproduction and aging per that theory but not between beginning of reproduction and aging. (Evolutionary pressure should increase with each reproductive event, until the last event. Genes that allow an organism to reproduce twice should have twice the evolutionary pressure than genes that allow a single reproductive event, for example.)

The data is somewhat consistent with antagonistic pleiotropy theory, if we assume that it is beneficial to have early puberty from a reproductive standpoint. But antagonistic pleiotropy has some other fatal flaws, as I previously mentioned, namely that it relies on circular logic.

No, the link between puberty and aging is exactly what you would predict if Red King Theory were true, and is consistent with what we observe in other organisms, like octopus, salmon, and many plants–reproduction triggers aging.

 

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