March 20, 2012

Brown eyed Neanderthals of Croatia

Since years ago, when one Neanderthal individual from Gibraltar was identified as having reddish hair color (but not via the Homo sapiens alleles but a different one of their own), some authors have idealized Neanderthals as hyper-white. For example the Gibraltar kid whose reconstruction is pictured at the right, whose skin looks unhealthily way too pale to be living in Andalusia (the Ice Age would not affect solar radiation in principle, only temperature).

Now other researchers have inferred that the Neanderthals from Vindija cave (Croatia) probably had brown eyes, hair and even skin, which is described as tawny, a light brown/orange shade.


The paper is widely discussed at a free article in Science magazine, titled: Were some Neanderthals blue eyed girls?, where the likes of Lalueza-Fox and John Hawks ponder the conclusions, rather critically. 

Of course, the conclusions are far from straightforward:


One complication is that traits such as hair color are controlled by multiple genes. To determine the cumulative impact of multiple genes on one trait, the authors assumed they could simply add together the impact of individual genes. The female Neandertal known as Vi33.26, for example, had seven genes for brown eyes, one for "not-brown" eyes, three for blue eyes, and four for "not-blue eyes." By the researchers' reckoning, that means a six-gene balance in favor of brown and a negative balance for blue, so Vi33.26's eyes were probably brown. According to this method, all three Neandertals had a dark complexion and brown eyes, and although one was red-haired, two sported brown locks. 

They may well be right in regards to the eyes, although we really know way too little on human pigmentation as of now, never mind Neanderthal peculiarities, to be certain at all. In any case, considering that modern Europeans also display variety of eye and hair colors, I see no reason not to imagine that Neanderthals also had dark eyes and hair.

Those traits are after all non-adaptive or mostly so. Instead skin color is key for survival. So I am reluctant to accept tawny as a valid answer for skin color, at least in most of the shades suggested. Very few people if any have tawny skin color today at 45 degrees North, roughly the latitude of Vindija. And that is because of an adaptive reason: the human need to synthesize normally vitamin D using solar energy at the skin (it can also be ingested from fish mostly but it's not as reliable in the long run).

Surely Neanderthals were also biological conditioned in that same way. Although now that I think of it I have never seen a paper stating it, just the same that I have never seen a paper that conclusively argues that Neanderthals lacked fur as we do, being our nearest cousins it is logical to think that they were a lot like ourselves. 

But regardless of the thornier issue of skin color, it's probable that at least many Neanderthals had brown eyes and dark hair and also a less hyper-pale skin shade than often misrepresented. In this sense I welcome the news because painting Neanderthals as ultra-Nordics, when they lived largely in Southern Europe and even West Asia was really overdoing it towards the side of pseudoscience. 

10 comments:

  1. They probably had an skin color called "olive", which some use to describe the skin shade of Southern Europeans and West Asians. If you look at modern S. Europeans, you'd find extremely pale individuals among them, yet my impression is that that's due to recent admixture with Northern euros: "natives" tend to have darker shades, and almost always dark hair and eyes.

    Croatians, though, seem to be quite pale...

    Also, is there any evidence that Neandertals had blue eyes? I understood that althought the two ladies had brown eyes, they also carried with them genes for blue eyes.

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  2. "Also, is there any evidence that Neandertals had blue eyes?"

    Not that I know. All comes from the red hair allele.

    "I understood that althought the two ladies had brown eyes, they also carried with them genes for blue eyes".

    That's what they say. But such "blue eyes" alleles also exist in Africa in some cases and they have no effect. I did not know there were so many and in fact had only heard before of two alleles involved in blue eyes: the famous HERC2 (or OCA2?) allele actually was blamed for 97% cases of blue eyes, but it could be more complex.

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  3. "whose skin looks unhealthily way too pale to be living in Andalusia (the Ice Age would not affect solar radiation in principle, only temperature)."

    My goodness, you love assuming things.

    First of all the sun may have been weaker during that time. Some people propose that was a cause or contributing factor to the ice age.

    Secondly we are talking about a very different group of people. Their vitamin D requirements, synthesis, and akin color system could be different.

    In our own time and species people on the same latitude have different skin colors yet you are trying to use those valuable skin colors (at 45) to guess the skin color of a different species at a different era. Wow... Just wow.

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  4. "First of all the sun may have been weaker during that time. Some people propose that was a cause or contributing factor to the ice age".

    If that would be the case, I'd be wrong. I just don't happen to consider it the most likely cause, but who knows?

    "Secondly we are talking about a very different group of people. Their vitamin D requirements, synthesis, and akin color system could be different".

    I think I address this issue in the penultimate paragraph: Neanderthals were not H. sapiens but H. sapiens is the closest living relative to Neanderthals, so assuming similitudes is not off the mark, but actually quite reasonable. Additionally, I didn't say but I must add now that the indication of loss of pigment suggested by their red hair does suggest that they were affected by the same conditionants re. vit. D and pigmentation, at least to some extent.

    "In our own time and species people on the same latitude have different skin colors"...

    Really? At 45 degrees North?

    French, Romanian, Georgian, Uzbek, Mongol, Korean.

    All them live near 45 degrees North, all have similar (not necessarily identical but pretty much the same) skin tones.

    Indonesians are indeed light for an Equatorial people however (but there's people who claim they are "recent" Neolithic arrival for the most part. Alternatively (my opinion) they might have arrived earlier (my opinion) but after having lost the genetics of "blackness" further North somehow. In any case they did not regain this characteristic once lost, the same that their Native Americans cousins didn't either.

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  5. "but actually quite reasonable."

    Guessing on a different species alone is a huge stretch imo.

    Well, at least you admitted the shortcomings and you are still valid in criticizing the super white neandertal.

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  6. "Guessing on a different species alone is a huge stretch imo".

    Conceded. But I'm sure you had read much more exaggerated speculations. I think mine are at least parsimonious, even if I can't be certain.

    (Deleting your duplicated comment, I'm sure you won't mind).

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  7. The pigmentation question doesn't really interest me at all one way or the other. I am much more interested in whether genetics will ever be able to determine hair distribution in archaic humans (we aren't there yet, not even close)

    Almost certainly the MRCA of Pan and Homo had fur. So when did Homo lose it and why? I am quite aware of the various speculations and "just so stories" various people have shared over the years, but there has never been any scientific evidence for any of these stories. The only scientific data are:
    1) the calculation that "body" (clothing) lice diverged from head lice circa 170 kya (error bars as large as the uncertainties in the genetic clock).
    2) the even softer estimate that Homo became hairless circa 1000 kya based on the evolutionary history of skin pigmentation genes

    If one accepts both of the above, one has to deal with the concept of unclad hairless Neanderthals running around in ice age Europe. Problematic indeed. My guess is that Neanderthals were "wooly humans" meaning like the wooly rhino and the wooly mammoth they re-evolved fur even though their tropical ancestors were nearly hairless. I have no evidence for this whatsoever, but neither do the artists who draw Neanderthals with Hs hair patterns have any evidence to support their beliefs.

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  8. Actually there´s one other theory. Not so popular these days, because the lack of its media-sexiness. You might have heard about the aquatic ape theory, often ridiculed by the self-proclaimed skeptics.

    It is based on the history of early australopithecines living on the forests around the Rift valley lakes and rivers. As the forest receded, the proto-australopithecines were forced to migrate closer to the shorelines were the forests could still thrive. Eventually the waterfronts became a source of nutritious food for the wading apes. Their long and wispy ape fur was disadvantage in an environment were one would get wet easily. A layer of fat could keep the warmth better than a wet fur. Wading also paved the way for a more upright stature.

    So according to this theory our ancestors lost their fur ca 4 million years ago.

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    Replies
    1. Aquatic ape my gills!

      That's a total nonsense. We know for a fact that the fur was lost for the same reason as tropical boars or elephants do not have it or other animals in such savanna environment have it short: heat!

      In fact, would we be "semi-aquatic" of sorts like elephants or boars, we would probably not sweat as we do, much more than any other animal.

      Reality check!

      Delete
  9. Hi Grizzlor, Maju should better inform a little bit before talking, but the littoral theory (a better term than AAT) is not about australopiths in the Rift, but about archaic Homo (erectus, neandertals & relatives) spreading along coasts as far as Flores island, the Cape & England (Pakefield & Bowgrove) & from the coasts inland along rivers.
    Some recent info:
    - Human Evolution conference London 8–10 May 2013 with David Attenborough & Don Johanson www.royalmarsden.nhs.uk/education/education-conference-centre/study-days-conferences/pages/2013-evolution.aspx
    - eBook "Was Man more aquatic in the past?" www.benthamscience.com/ebooks/9781608052448/index.htm
    - recent guest post at Greg Laden's blog scienceblogs.com/gregladen/2013/01/30/common-misconceptions-and-unproven-assumptions-about-the-aquatic-ape-theory/
    - discussion forum tech.groups.yahoo.com/group/AAT

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