Because we have found evidence indicating at least one introgressed gene appeared in the M.E. 37,000 yrs ago %26amp; spread to 70% of the population (remaining very rare in Sub Saharan Africa) is it reasonable to develop the hypothesis that Europeans got their hair, skin %26amp; eye color from Neanderthal due to their closer association with that group. For some reason only Europeans developed these traits.
Other groups that occupy a simular environment to Europeans did not develop light hair or eyes %26amp; Europeans did have the most prolonged contact with the Neanderthal.
Before some of you give me the obsolete stuff about no evidence of Neanderthal %26amp; Homo Sapien having interbred, read the following links. Bruce Lahn's team from U of Chicago found a 1.1 million yr old gene that suddenly appeared in a species that was only 200K yrs old... this gene "introgressed" into the human genome 37,000 yrs ago.
http://www.sflorg.com/sciencenews/scn110...
http://www.johnhawks.net/weblog/2004/11/...
Did Europeans get skin, hair %26amp; eye color from Neanderthal?
I think that considering the soft ground that the introduction of this "retrogressed gene" is sitting on as far as it's arrival and dispersal is concerned within contemporary genetics, as I explained in my other posts to you, that to conclude that these characteristics came from neanderthal interbreeding is sketchy at best. To conclude such a hypothesis would also require an untangling of the neanderthal genome project, much like Lahn's other conclusions that attempted to conclude differential intelligence and reasoning based on the introduction of this same gene interaction. And even the neanderthal genome project will not be 100% conclussive given the lack of DNA evidence for other Archaic Homo populations. Also while reading your question, I don't think that it is actually correct to refer to the previous DNA evidence as "obsolete stuff" because after doing some extensive readings on Lahn it has become very apparent that while his ideas are novel and unique, his hypotheses are actually quite reaching and have by no means replaced the genetic evidence that as-of-yet is still solidly entrenched within this area of genetic study. To add that comment is a bit leading as it implies that Lahn's studies have passed through the peer review process and have stood up to the empirical evidence that new hypothesis are put up against. Since neither of these conditions have been completed it is still too early to declare the old evidence as being "obsolete stuff" and to do so is to commit the same error that Lahn committed in being overzealous of a hypothesis still in its infancy. So your actual question is not yet fully answerable given that Lahn's studies have not yet passed through into the body of contemporararily accepted hypotheses, but based on the former school of thought which is still the vast majority of the genetic community, no Europeans did not get their skin, hair %26amp; eye colour from neanderthal.
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In response to your additional details, the evidence that is being introduced by Lahn is based on genetic sampling of the contemporary populations to determine the gene frequency within different regions and then based on a linear growth (which is not always true for the spread of genes) predicted an originating date of 37,000 and then based on the relative percentages in the population he decided that Europe would be an adequate location for its introduction, but could just have easily have choosen the Middle east or Asia IMHO. In fact considering that this gene was present in the pre colonial New World populations I don't quite understand why you believe that radiating from Europe would be any more practical then radiating from Asia back into Europe and the Middle East along with radiating into the New World with the Mongol migration 10,000 - 12,000. It would be interesting to know if early archaeological finds like Kennewick man also had this gene to really pin down which migration to the New World contained it, but as of yet there is no archaeological DNA finds for these early migratory populations, but as some N. American regions are cooler the possibility of DNA evidence is not impossible. Anyways, let me stop digressing from the point. Asia or the Middle East, being more centralized, would allow the radiation to all carrying populations to occur more quickly then if it originated in Europe. Plus the 37,000 date is by no means set in stone. Perhaps the gene was geographically confined for 10,000 years or more before it began to spread throughout the world, or perhaps it spread more quickly then he realized and this time frame is too long? Anyways, 37,000 is very convenient if your intention is to try and influence this neanderthal hypothesis, but is not a 100% factual conclussion based on his "evidence". A bottleneck in gene flow would have been easier when the gene was within a smaller population and it could be easily suggested that this gene's introduction should be given a range, perhaps 35,000 - 65,000 years. Now since Lahn is allowed all the leniency to hypothesize then lend me the same leniency. Lets say for instance that since anatomically modern Homo sapiens were present in the Middle East at 90,000 then it would not be to hard to say that they were at the Black Sea by 71,000, which happened to coincide with a cooling period. The Black Sea swelled from this cooling and a group of moderns became trapped on the land mass on the north side of the Black Sea which became a large Island. The Black sea was teaming with fish and as this group became increasingly sedentary in this trapped location they became a proficient fishing culture. For the next 12,000 years their group was cut off because the cold weather kept the water higher and less hospitable to attempt crossing it. They were happy though, eating plentiful amounts of fish to keep their body fat up for warmth as they did not have clothing yet (there was no evidence of clothes in the archaeological record until clothes mites became present around 60,000 ya). This high fatty diet caused an increasing foetal body and head size and this small population was heavily selected upon for genes that made reproduction of these big babies easier. One of these gene mutations that occured was that of the MCPH1 and rapidly spread throughout this small trapped group because it was the best solution as it allowed a smaller foetal head size and then the MCPH1 gene kicked into action to express itself post delivery to allow the head size to continue to reach the appropriate size for mature Homo sapiens. The group was now able to thrive in this environment with their high fat diet and persisted until the cooling period began to decrease 59,000 years ago. Ironically, looking at the climate records the climate progressively warmed until 37,000 and this coincided with this groups peak reintroduction into the greater Homo sapien population in the Black Sea area. Despite this reintroduction into a much larger population, the genetic expression of MCPH1 had a continued success and rapidly spread throughout Europe, Asia and even into the New World because it allowed a far greater reproductive success because there were less still births and a greater percentage of mothers survived the birthing process when their babies were carriers of this MCPH1 gene. Here is one of many contending hypotheses that can be created out of thin air that are also supported by the "evidence", only unlike Lahn's hypothesis I included climatological data and entered the concept of a restricted population because these conditions frequently go hand in hand with quick evolutionary changes so it seemed right to look up what was going on at the time and this hypothesis that I claim full credit for fits all the "evidence" very nicely. The point is that I could go on and on creating credible solutions that fits the evidence that is actually being put forth by Lahn and these hypothetical scenarious don't neccissarily have to include neanderthal interbreeding or an introduction of 37,000 years ago, because these are just speculation! The problem isn't that there is a lack of evidence that goes against what he says, it is that the actual evidence which is being put forth is just the modern gene percentages, yet and his conclusions are so speculative and narrowminded when they data can be made to fit any number of extremely probable models, and if you include into the model some typical evolutionary pressures they even seem to become a lot more credible. The sheer vigor in terms of the reproductive success that Lahn's evidence shows must mean that it was a heck of a gene and you should still see some advantage in modern populations! Instead of being fixated on something like intelligence which is so similar between cultures that it would be hard to quantify in any kind of realistic unbiased scientific study. So similar infact that it surely could not be causing such a drastic differential reproductive success because the difference is next to nil. In a reproductive sense with regard to foetal head size, however, this could have been a very important way that this gene could have expressed itself, and it would be somewhat measurable in the real world today. Is the modern mother of a non MCPH1 child more likely to have to go for a cesarian when the pregnant mother comes from a culture that enjoys high fatty/calorie diets? Babies heads are always measured at birth, is their any slight size difference between MCPH1 babies and non MCPH1 babies at birth, even a third of a centimeter would be significant in changing the birthing process and life/death ratios in pre-ceasarian times, or if the babies genetics had a better ability to contort their head to that long bannana shape because of this gene that could also be a very strong selective pressure? Does a poor diet, like what is seen in many areas of Africa supress the spread of this gene because it no longer has as much selective pressure seeing as the head sizes are already being supressed from nutritional deficiencies? You have had eight children so surely you can rationalize with the birth process being a key moment for genetic expression to assist that process in whatever means possible, also remembering that 65,000 years ago their were no hospitals to go to and no emergency ceasarians to step into to alter reproductive success, so it was even more of a selective pressure then. The more I write about my own hypothesis, the more I get convinced by it, but I'm not going to go to nature or science journal to try and get it published to contend with Lahn's hypotheses, I would sooner look at the statistical evidence of MCPH1 babies and non MCPH1 babies regarding head size and cesarian births, see what effect nutritional input during pregnency has on foetal head circumference, etc... and I would do this before I went running my mouth off with such wild speculation to the journal presses. There is a scientific route to follow, and quite frankly, Lahn stepped off that route with his presentation of the "conclussion" of his genetic study. Perhaps he should have given an array of interpretations if he wanted to find the fame from being part of interpreting a new theory, but to only interpret his evidence in one hypothesis as some kind of leading contender without the appropriate supporting evidence was a serious mistake, unscientific, and if he didn't realize this then he should sooner have kept his mouth shut regarding interpretation and just presented the genetic facts that his team discovered and waited to determine any and ALL credible hypotheses after the appropriate empirical evidence was provided in support of the various hypotheses that can be created from this "evidence"..
Did Europeans get skin, hair %26amp; eye color from Neanderthal?
Even I don't entirely agree with myself. A good hypothesis requires much more then a few hours of thought and a heck of a lot of empirical backing to gain ground and support. But I feel that it is also very important to question other hypotheses as well. Report It
Did Europeans get skin, hair %26amp; eye color from Neanderthal?
A good counter hypothesis that makes use of the same "evidence" is usually a good way to do this. This 300 character thing is really annoying! You know I like to write endless replies... Report It
Did Europeans get skin, hair %26amp; eye color from Neanderthal?
Thanks for giving me the best answer, and for providing me with the instigative motivation to think about this question. It has been an interesting exercise in thinking through genetic data and its interpretation. Report It
Did Europeans get skin, hair %26amp; eye color from Neanderthal?
Yes, I have read such, but as everything else in science, we must mull the data over first and seek more corroborative support. This is not written is stone, either way. So, you may be right and then again, the data may not hold up. Too soon to tell.
In science, minds change when enough evidence has amassed to change them. I can not speak to anthropology, a social science. They, even though two lines of genetic evidence point to it ( Y chromosome and mtDNA ) still hold out the " regional replacement model as " in the running. Go figure.
Did Europeans get skin, hair %26amp; eye color from Neanderthal?
It's not out of the question...
One theory postulates that some of the cold-adaptive Neanderthals actually had blue eyes and blond hair...
The further north you go in Europe, the more blue eyes and blond hair you will encounter, and the further towards the Mediterranean, and its shores you travel, the more brown hair and brown eyes you will see...
Did Europeans get skin, hair %26amp; eye color from Neanderthal?
No...there is no evidence, apart from 1 or 2 examples of "hybrids" between the 2 species.....Remember H.neaderthanesis is NOT considered to be a direct ancestor of H.sapiens, but rather a cousin that died out ( and had some interbreeding with)......The common ancestor to both, maybe H.heidlebergensis may have had the gene and passed it to both species....but as H.neaderthalensis died out and is not a direct ancestor, it cna't have been passed to H.sapiens.
Did Europeans get skin, hair %26amp; eye color from Neanderthal?
It could be. Various Sources including National Geographic and Scientific American, and scholars + archaeologists worldwide have found a decent amount of proof that Neanderthals Interbred with the group living in Europe at the time. However another reason for the difference in skin tone and eye color may have been the climate. In Africa, there was more sun, and higher temperatures while living in europe for one thousand years gave H Sapiens adaptations to blend in better with the environment. That would explain skin and hair color. Polar bears' fur are clear and either reflects the color of the snow or the color of their skin (i don't remember which) they reflect white so that they blend in better whereas the Black Bear blends into its forested environment better. And i don't know advantages Vs Disadvantages for the eyes concerning climate so that may be becaus eof the Neanderthal Groups that interbred.
Did Europeans get skin, hair %26amp; eye color from Neanderthal?
My gut feeling is it was the contact between these two races or there is another branch as yet unknown because of its similarity to the Saharan. Science tell us, we are an accident. To me there is a plan to this madness. I have bred rabbits for a good number of years and if you line breed you continue to have the same color of rabbit but if you breed outside the line can bring in another color. All the text I have read say we come from the same limb but are different branches if so where is the outside trigger. You can not have so many changes in one breeding.
Did Europeans get skin, hair %26amp; eye color from Neanderthal?
I really should not even attempt to answer you, but I do find it immensely interesting.
One might also take into account Bushy Eye-brows! Africans don`t seem to have that as a characteristic. I believe Celto-Ibericos were known to have bushy eye-brows?
Also.. I often wonder if a lot of evidence of Neanderthal man disappeared under the sea when, if the evidence is correct, the seas rose some thousands of years ago. I seem to remember being told once that Neanderthal man lived close to the sea, preferring that ambiance to the Mountain.
In any case, I like your theory and I think your argument holds a lot of weight.
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