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Humans Are Still Evolving And It's Producing Some Amazing Results

The best is yet to come.

07/09/2017 10:56

Humans might consider themselves the final stage of evolution - the pinnacle of millions of years of genetic improvements that have made us the ultimate prototype for survival that we are today.

But according to researchers from Columbia University humans are still evolving, as harmful genetic mutations that cause people to die prematurely, are gradually being weeded out over time.

Study coauthor Joseph Pickrell said: “It’s a subtle signal, but we find genetic evidence that natural selection is happening in modern human populations.”

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Looking at genetic data from of 210,000 people in the USA and Britain researchers found that genetic variants linked to Alzheimer’s disease, heavy smoking, heart disease, cholesterol, obesity and asthma are far less frequent in people with longer lifespans.

As with all evolutionary development, favourable traits emerge over a period of time when genetic mutations offer one pool of people a survival edge over the rest of the population.

The survivors of each generation of that group then pass on their superior genes, which gradually become more widespread in the general population.

Although it takes millennia for say, humans to walk on two legs instead of four, each generation has tiny adaptive mutations that can be traced.

And in the study, they found that there was a drop in the frequency of the ApoE4 gene linked to Alzheimer’s disease in women over 70-years-old, which is consistent with other research showing that women with one or two copies of the gene tend to die well before those without it.

They also saw a similar drop - starting in middle age - in the frequency of a mutation in the CHRNA3 gene associated with heavy smoking in men.

They also found that those genetically predisposed to delayed puberty (and therefore childbearing) lived longer.

It only took a one-year puberty delay to lower the death rate by 3-4% percent in both men and women. And a one-year childbearing delay lowered the death rate by 6% in women.

Molly Przeworski, who co-authored the study, said: “It may be that men who don’t carry these harmful mutations can have more children, or that men and women who live longer can help with their grandchildren, improving their chance of survival.”

But the study, which may be the first of its kind, also concluded that these traits might not last forever.

Lead author, Hakhamenesh Mostafavi, said: “A trait associated with a longer lifespan in one population today may no longer be helpful several generations from now or even in other modern day populations.”

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