Evolution and humans;hybridization (Evolution)

by David Turell @, Sunday, October 18, 2015, 23:02 (1339 days ago) @ David Turell

Many of us have some Neanderthal, and many Asians some Denisovan:

http://www.bbc.com/earth/story/20151013-how-interbreeding-shaped-us

"If your ancestors hail from anywhere outside Africa, it's a safe bet that you are part-Neanderthal.

"After modern humans first left Africa, they came into contact with Neanderthals and things got cosy. These early frolics are now visible in our DNA. Genetic analysis indicates that Europeans and Asians obtained 1-4% of their DNA from Neanderthals.

"It seems everyone was at it. Neanderthals interbred with another species, the Denisovans, as did some of us. Some people from South East Asia have up to 6% Denisovan DNA.

"Even Africans whose ancestors never left the continent carry some Neanderthal DNA, because 3000 years ago people from Europe and Asia migrated to Africa. Many modern Africans have inherited some genes, including some Neanderthal ones, from these people.

***

"Brown bears and polar bears can successfully interbreed when they meet. Most of the Galápagos finches are the result of interbreeding, as are many primate species like baboons and gibbons.

"'Seven to 10% of all primate species hybridise, which is common considering a lot don't ever come into contact with each other," says Rebecca Ackermann of the University of Cape Town in South Africa.

"In July 2015 it emerged that a hybrid coral is doing better than either of its parent species. It can survive in a busy shipping channel, which its parents cannot do.

***

"Interbreeding can speed up these changes, says evolutionary geneticist Rasmus Nielsen of the University of California, Berkeley in the US. When modern humans left Africa, integrating with other species therefore allowed us to adapt to new environments much more quickly.

"For example, the DNA evidence hints that we inherited the ability to fight certain diseases from Neanderthals. When we first arrived in Europe our immune response may have struggled to deal with unfamiliar local diseases, but the offspring of those that interbred with Neanderthals fared better.

"The same occurred when Europeans began colonising the Americas, bringing diseases that proved catastrophic to the indigenous population. "The ones that survived were products of mating between Europeans and North Americans," says Nielsen. "Something similar happened, but maybe on a grander scale, between Neanderthal and modern humans.'"

Comment: Hobbits not mentioned. Hybrids have a wider spread of characteristics which would help in survival.


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