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Tuesday, September 19, 2017

Massive genetic study shows how humans are evolving

Bruno Martin
Nature
Originally published 06 September 2017

Here is an excerpt:

Why these late-acting mutations might lower a person’s genetic fitness — their ability to reproduce and spread their genes — remains an open question.

The authors suggest that for men, it could be that those who live longer can have more children, but this is unlikely to be the whole story. So scientists are considering two other explanations for why longevity is important. First, parents surviving into old age in good health can care for their children and grandchildren, increasing the later generations’ chances of surviving and reproducing. This is sometimes known as the ‘grandmother hypothesis’, and may explain why humans tend to live long after menopause.

Second, it’s possible that genetic variants that are explicitly bad in old age are also harmful — but more subtly — earlier in life. “You would need extremely large samples to see these small effects,” says Iain Mathieson, a population geneticist at the University of Pennsylvania in Philadelphia, so that’s why it’s not yet possible to tell whether this is the case.

The researchers also found that certain groups of genetic mutations, which individually would not have a measurable effect but together accounted for health threats, appeared less often in people who were expected to have long lifespans than in those who weren't. These included predispositions to asthma, high body mass index and high cholesterol. Most surprising, however, was the finding that sets of mutations that delay puberty and childbearing are more prevalent in long-lived people.

The article is here.

Note: This article is posted, in part, because evolution is not emphasized in the field of psychology. There are psychologists who believe that humans did not evolve in the way other plants and animals evolved.  I have argued in lectures and workshops that we humans are not in our final form.
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