Genome of Neandertals Reveals Inbreeding

sciencehabit writes "In a report on the most complete genome of a Neandertal ever sequenced, an international team of researchers has found that the parents of a Neandertal woman from Siberia were as closely related as half-siblings. The genome also shows that at some point the Neandertals interbred with other human groups, including their cousins the Denisovans, and our own modern human ancestors. There are even signs of Denisovans interbreeding with a mysterious archaic species. In all, the study suggests very close encounters among the several kinds of hominins living in the past 125,000 years. The detailed genome of the extinct Neandertals—our closest relatives—also offers a new look at the genetic differences that set our species apart from all the others."

Comments

Not surprising

[JasoninKS]

Not a surprise really. There weren't exactly large groups running around to intermingle. You want to procreate and expand the species you had to look within your own local group.

Re:Not surprising

[Runaway1956]

Agreed. What is so surprising about some inbreeding? The human animal is an animal after all. Take any animal, and set a limited population apart. They're going to mate, and that population will continue mating, until something happens to reintroduce that limited population back into the larger population. It isn't a matter of preference - it's a matter of necessity.

Once reintroduced into the larger population, some limited inbreeding may or may not continue. But, interbreeding is going to happen as well.

Life. What a concept. Life struggles to continue, under all conditions.

Re:Not surprising

[quantaman]

Taboos against inbreeding are hardly the result of intolerance since inbreeding drastically increases the probability of recessive genes becoming expressed. Since recessive genes are rarely expressed they're not exposed to the same selection pressure and tend to be less fit as a result.

So your claim is that by engaging in inbreeding, we are putting evolutionary pressure on the recessive genes, thus removing them from the gene pool, and that this is beneficial?

Beneficial for the species possibly, but not for the poor individuals who are tasked with the job of carrying those genes out of the pool.

(though it might be bad of the species as you'll lose some diversity too, recessive genes still get selection without inbreeding)

You are aware that, if you have a single gene for sickle cell anemia, rather than coming down with the disease, you're effectively immune to Malaria, since the blood cells will sickle in the presence of Malaria, but not otherwise, right?

http://www.sciencedaily.com/releases/2011/04/110428123931.htm

Recessive genes are less fit on average, that doesn't mean in some instances they can't be as or even more fit than their non-recessive counterparts.

The sickle cell gene example, aside from being fascinating, actually proves my point. It would not have survived as a dominant gene in that form since the side effects of full expression are too harmful, it either would have been removed from the genepool, mutated to only go sickle with Malaria, or another gene would have popped up that made it only go sickle with Malaria. It's the fact that it's recessive that's allowed it to retain such poor fitness.

Re:We're all the same...

[Empiric]

I'm persistently surprised also by how often evolutionary biologists seem oblivious to the notion of a "birth defect".

Note that I am not saying that evolution didn't happen. I'm saying that species categorization and the "evidence" for them have become so scientifically loose that the claims are unfalsifiable.