Friday, October 26, 2007

Red-Headed Neanderthals

Neanderthal was a species of Homo genus that inhabited Europe and parts of Western Asia. Once the Neanderthals were considered by many to be our ancestors but now many consider it to be an evolutionary dead end. The Neanderthals appear in the fossil record about 400,000 years ago. Our own species of Homo sapiens evolved in Africa and displaced the Neanderthals after entering Europe about 40,000 years ago and drove them to extinction about 28,000 and 24,000 years ago.

A team of researchers extracted DNA remains of two Neanderthals and found an important variation of a gene called MC1R.
In humans a change or mutation in this gene causes red hair. Analysis of this gene has revealed that the Neanderthals had red hair and pale skin color. They found out this gene causes a pale skin and red hair by inserting the Neanderthal gene into a human cell called melanocyte. Melanocytes produce a pigment that give the hair, skin and eyes their color. Researchers saw the same loss of function in the Neanderthal gene that produces the same hair color as in the modern red heads. Having pale skin along with red or blond hair seems to go hand in hand and seems to be evolutionarily advantageous for people who live further away from the equator such as in Europe. So people with fair skin are able to generate more vitamin D which gives them an evolutionary advantage. So any mutation that falls into the MC1R gene is allowed to survive and spread through a population. Research suggests that similar adaptations were evolved independently by Neanderthals and modern Europeans in response to similar environmental circumstances.

This pioneering work on the biology and physical appearance of Neanderthals is important because it addresses key questions such as why we inherited the Earth and not the Neanderthals. This work is mostly done through DNA analysis by various geneticists and biochemists. This research suggests that there is a propensity to reduce melanin in populations that inhabit areas away from the equator where sunlight levels are low. If the Neanderthal and modern variants of this gene are different this is a good example of convergent evolution, a similar evolutionary response to the same situation.

Posted by: Balkrishna Gantyala(5)


At 8:27 PM, Blogger PWH said...

I thought that the format of your blog was extremely well written. Each paragraph had something interesting to say.

I hadn't ever thought about how red hair and pale skin could be advantagous in some areas. I found that part of your blog to be very interesting. Maybe you could go into more detail about that and explain if that played some role in Neanderthals dying out. Or, give a counterexample about if people with darker skin lasted longer evolution-wise.

Nice work, I really liked it.

Posted By:
Natalie Nicholson (5)

At 9:41 PM, Blogger PWH said...

This post seems very interesting. I really feel like i got a very different perspective about the Neanderthals. This article is also well written. Usually everyone concentrates on animal behavior but you actually took a side track and gave us some genetic background. It would be helpful to have more background information on what actually happened to the Neanderthals after a while. And also have you found any other articles that support this research? Great post overall!

Posted by:
Swetha Raghavan (5)

At 11:06 PM, Blogger PWH said...

I was really fascinated with this article. Well done. I wasn't aware that there was much research being done to determine such facts. Very well presented and makes us think what exactly we took for granted. Makes you wonder if things have gone the other way how it would have been. Well Done.

Posted by:
Kirubakaran Sivagurunathan


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