Talk:Human skin color

new theory

What about the new theory that melanin is an anti-infection agent and that rather than people evolving lower melanin in order to let in more light, they did it because they weren't as healthy and so couldn't afford the metabolic cost of melanin production? According to this theory, melanin corresponds to humidity levels (which many viruses and bacteria depend on) instead of light levels. --Ark

Hum, -- never came up in my immunology, antomomy or human evolution classes and I can't find anything about it on Google either. It does sound interesting. Do you have a webpage or better yet a peer-reviewed journal article to point me to for more information? --maveric149, Tuesday, June 11, 2002

Heh. It came up either in Scientific American or New Scientist. Probably sometime in the last year. In the last two years definitely. :)

Basically it was speculation based on some preliminary finding. I don't remember what the finding was though. I just mentioned it because like you said, it's so interesting. -- Ark

Cool I try to find it. It's probably a bit too new and unvarified to include in this article though. --maveric149

What does this mean?

In general, people with recent ancestors in sunny regions have darker skin than people with recent ancestors in regions that lack much sunlight.

Was the above sentence intended to support idea that acquired characteristics can be inherited? I thought Lysenkoism had been thoroughly discredited. --Ed Poor 19:59 Sep 6, 2002 (UCT)

I think you can get that with usual natural selection arguments. White skin is more susceptible to skin cancer, so you could eliminate them from the gene pool because of that.AstroNomer (Who is not a biologist and is just waving hands)

I also am not a biologist. However, my understanding is:
- If you are born light-skinned in a region with intense sunlight levels, your chances of skin cancer are much greater. Ergo genes for fair skin are much less likely to be passed on. There are probably other factors like increased vulnerability to disease as a result that would intensify this.
- If you are born dark-skinned in a region with low sunlight levels, your body doesn't synthesize as much of a certain nutrient (vitamin D?), which is best catalyzed by sunlight on skin. Ergo, your resistance to disease and such goes down, and again, your genes are far less likely to be passed down through the generations.
Over many generations this dual selection effect may lead to the grouping of prevalent skin colors according to the amount of sunlight received by, oh, the past few hundred generations in a given locale. -- April

Right, I understand about the "genes being passed on" part. And it accords with ethnographical observations of Northern Europeans being light-skinned and equatorial Africans and Caribbeanns being dark-skinned.

My confusion was about the "recent ancestors" claim in the sentence I first quoted way above. I'd like to revise it so it doesn't give the impression that the process takes place over a couple of generations. Doesn't it take centuries before we start to see any significant differences? --Ed Poor

I see what you mean. Probably he was meaning e.g. african-americans: they have "recent ancestors" from Africa, that were dark skinned because they had had lots of ancestors living there. There is a step missing in the chain.AstroNomer

Going out on a limb here, with my shaky bio knowledge, but I'd guess that the genes for most skin levels would be present, if not common or commonly expressed, in just about any population. So if two groups of humans colonize a high-sunlight planet and a low-sunlight planet, and then are cut off from intermarriage outside the group, we'd start seeing significant changes between the populations in... well, if you take a "generation" as about 20 years... at a very rough guess, maybe a few centuries?

I suspect that by "recent" the person was thinking "hundreds or thousands of years in the same place" as opposed to, say, ten thousand to a hundred thousand years, which is (I think) the scale of many major population migrations. Add a lot of caveats that I could be talking complete nonsense here, 'cause I'm far from expert. :) -- April

I thought of "recent ancestors" as not more than 4 generations back, like my great-great-grandparents, who are Polish and Russian Jews (on my mother's side). Thanks for the scientific help. I think I have enough information to edit the article.

What means "The lighter skin of women results either from sexual preference or from the higher calcium needs of women during pregnancy and lactation."??? Can I see the ``sexual preference of a woman in her skin color?

-M

What he is trying to say is that women with lighter skin are supposedly prettier. He should look at Beyonce Knowles and reconsider. Cameron Nedland 03:33, 29 December 2005 (UTC)[reply]

There is a school of thought suggesting that light skin, blond hair, and pale blue eye color arose in part among European populations during the last Ice Age as a way for females to attract males. The lighter-skinned females stood out from the others and were more "exotic," hence more desirable as mates. There is solid evidence that there was a gender imbalance in Europe at that time (for varous reasons), and that strong males were in shorter supply. So in addition to other environmental factors selecting for light skin, demographics may have also played a role. Sociobiologists can see in populations today that small numbers of different looking females are viewed as particularly attractive sex partners by dominant males. On study in Finland showed that while racist views were quite prevelant in the overrall population, the small population of young black and asian women resident there received a higher degree of sexual advances from Finnish males than the average young ethnic Finn did; the "exotic" theory at work.

In general, however, given the smaller number of very light-skinned females in most societies, it will be these who are considered the most attractive, Beyonce notwithstanding.

Recent studies on internet pornography tend to support this. Both black and white males are drawn in far greater numbers to websites featuring light-skinned, white girls. There are, of course, sites featuring Latinas and black women, but far fewer. None of this is politically correct, of course, and most scientists won't touch these issues. I work in a related field myself, and I admit that I won't sign my name here because of the fear of being labelled racist, etc.

I don't think any of that means that light-skinned females are "better" than dark-skinned females, etc. That's not what it's about. And cultural factors are obviusly involved too. But there is quite a bit of rather dry evidence to support that in general, males in most populations are somewhat "hard-wired" to prefer light-skinned gals over dark-skinned ones.

Let's put it this way. As any biologist will tell you (and I'm one), all animals use visual markers and signals to attract and select mates, and obervation of any species will identify certain physical characteristics, especially marking and color patterns, that invariably attract more attention. Humans are no different. Difficult for us to talk about or admit given the way that "race" has negatively impacted so many people throughout the world. But from a cold scientific standpoint, it's true.

Why/how is it that the Tasmanian Aborigine, a population isolated for thousands of years so far south, retained such dark skin? Tasmania is as close to the South Pole as Southern Europe, mid-North-America, or Japan is from the North, and the populations of those areas were much lighter. -- stewacide 20:39, 18 Mar 2004 (UTC)

I'm a tad confused as well. For vitamin D production, the amount of time spent in the sun is trivial -- say, about 15 minutes/day, for a light-skinned person. For a dark skin person, they might need 6 times that -- Say, an hour and a half. Thus, the skin-color/vitamin D link seems a tad weak. I believe Darwin wanted to chalk skin color up to sexual selection. The Tasmanians have been isolated in Tasmania for thousands of years -- the disappearance of the Tasmanian-Australia landbridge is known. At the same time, the retreat of the glaciers from northern Europe happened later. But the typical northern European has light skin, Tasmanians have dark skin.

Is the skin color link appropriate?

The external link to Asian skin color should be deleted. The site that the link takes you to is not a scholarly source, but merely a joke-website made to ridicule asians. -- 70.105.1.158 (from the PageHistory)

I changed the description of the site. Is that better? I looked at 1) the linked page and 2) other pages on that site. The person who put up the site has a definite point of view. I would summarize that point of view as follows. There is nothing special about Asian skin color or Non-Asian skin color. In fact, the variations in Asian skin color are caused by variations in the same combinations of three parameters that cause variations in the skin color of people everywhere. The three parameters are: 1) vegetation reducing UV radiation striking human skin over many generations, 2) persistence of snow cover increasing the UV radiation striking human skin over many generations, and 3) closeness to the equator that increases UV flux over many generations. Would you agree? Also, please sign the end of your postings with 4 ~ marks so that the computer will insert your signature and time of your posting. Thanks. --Rednblu 01:51, 21 May 2006 (UTC)[reply]

van Luschan scale

Felix von Luschan, (1854-1924)

In anthropology, verbal descriptions of skin colors ("white," "yellow," "black," "brown," and "red") were replaced by color-matching methods during the early twentieth century (Olivier 1960, von Luschan 1897). The most popular of these methods was the von Luschan scale, based on the use of colored tablets or tiles of different colors and hues with which the colors of unexposed skin were matched. These and similar matching methods could not be consistently reproduced, however, and were swiftly abandoned when reflectance spectrophotometry was introduced in the early 1950s

[1] dab 11:55, 28 Nov 2004 (UTC)

Eyes color

Non-white people are only brown-eyed, it's impossible for a non-white person to naturally have non-brown eyes, the only way is to have one white parent, & one non-white, then he/she may earn his white parent's eye-color, which may be blue, green or hazel, but multiracial people are very rarely non-brown-eyed.

Thats far from the truth, their are a lot of dark-skinned people on both sides that Have light eyes. Not that light eyes are anything to admire. --65.188.253.47 01:09, 3 January 2006 (UTC)[reply]

When I was in India there were people there (that were darker than most blacks) that had blue eyes.Cameron Nedland 16:36, 17 February 2006 (UTC)[reply]

Forget it, I'm full Chinese and my right eye is already look hazel while left eye is golden brown.

Person who put that about it being impossible for a non-white to naturally have non-brown eyes, you were greatly misinformed.

Not necessarily. See Indo-Aryan migration, Tocharians and Seres for information on why some "dark-skinned" groups, especially in India and China, may have white admixture. --Jugbo 21:46, 10 May 2006 (UTC)[reply]

Mmm. I just noticed this: "not that light eyes are anything to admire." Well, yes, they are. They're a reproductive, or sexual, adaptation, meaning that they confer no environmental advantage, like camouflage or speed, on their carriers, who are rather supposed to look better to the opposite sex because of them. They're similar to art. Whether or not you personally like Michelangelo's David, it was meant to be admired. --Jugbo 15:36, 26 May 2006 (UTC)[reply]

Cutting two dubious "See also" links

, History, Tom Irwin.

The above two links were inserted by User:80.46.154.123 at this edit. Going out of my way to assume that this prank was done in Good faith, I am leaving this record for someone to revert if generic History and "Tom Irwin" are renowned experts in Skin color that I cannot find in Google. 8)) ---Rednblu | Talk 19:10, 22 Dec 2004 (UTC)

latitude

File:Map of skin hue equi.png

Historical data for "native populations" collected by R. Biasutti prior to 1940. Darker shades represent darker skin color.

Note however, that "darker shades" of skin color correlate, not with latitude, but with a thousand-year cumulation of 1) total annual UV striking the ground through the cloud cover and 2) lack of sources of Vitamin D in the diet such as from fresh fish. Hence, notice the darker shade of skin color at the equator, comparing South America to Africa--because there is much more cloud cover annually over South America. See text.

it seems strange to say that skin colour is not correlated to latitude but rather to the amount of UV radiation, since clearly the latter is correlated to the former. dab (ᛏ) 19:50, 22 Dec 2004 (UTC)

For example, if you look at the map, natives to Africa have much darker skin than natives to South America at the same latitudes. That is because there is much more cloud cover over South America than over Africa. Good suggestion! :) I will add an explanatory note to the caption to make your point clear. ---Rednblu | Talk 23:04, 22 Dec 2004 (UTC)

You'll need an entire subsection soon. But I don't agree with your interpretation. Note that the "natives" of South America immigrated some 20k years ago, the Australians some 70k years ago, while the Africans were in Africa "forever". So even if there was as much Sun in South America as in Africa, people may not have been there long enough to adapt. Your explanation is simplistic, as if humans were uniformly distributed on the Earth at one time and then started to adapt. Human migration is at least as important a factor for explaining the patterns. e.g. the pink corner in South Africa is not due to a permanent cloud-cover, but almost certainly to inter-marriage with immigrants. dab (ᛏ) 08:47, 23 Dec 2004 (UTC)

That's all right. You missed the Jablonski 2000 article. [2] No big deal. 8)) The adaptation takes place in a few thousand years. And the data is only for "Natives" who have been relatively fixed for a thousand years. No intermarriage is in the data. You can compare the raw data in the tables at the back of the Jablonski article to the map. ---Rednblu | Talk 12:16, 23 Dec 2004 (UTC)

interesting. although I find it hard to believe. this borders on Lamarckism. Do you mean the map on page 77? I'm sorry. I am not an expert, but I suppose unless the data is cross-referenced to genetic analysis (mitochondrial etc.), the matching of skin shade to latitude is rather pointless. You would have to show that adaptation is quicker than migration, eg. for South Africa. Do they say somewhere that South Americans are lighter because there is less UV there than on similar latitudes in Africa? Anyway, I don't have the time to dig into this right now, so I just assume you are right. dab (ᛏ) 14:54, 23 Dec 2004 (UTC)

also, your caption is suggestive that the map should be taken at face value. While it is of course good enough to give a general idea, I was very careful to state on the Image page that it is outdated, and should not be used as an up-to-date reference. dab (ᛏ) 08:51, 23 Dec 2004 (UTC)

The inuit are probably a poor example, since high latitudes have alternating patterns of extremely high (or at least constant) sunlight followed by almost none. so far the adaptations i'd heard of included the narrow eyes.. though now that i think of it, that's universal mongoloid, so that makes no sense. anyway, i've never seen a 'relatively dark' inuit, so that part doesn't make sense to me.

The Inuits/Eskimos (I'm not racist) were able to survive with their dark skin at northern latitudes because a huge part of their diet, the seal, has a lot of vitamin D.

Cameron Nedland 03:33, 29 December 2005 (UTC)[reply]

About that map

I've deleted the above image from the article.

"Be bold." Well, I removed the above map.

When I first saw this image, my first reaction was, "This can't possibly be correct!" I Googled it, and the first thing I consulted was this.[3] I don't know where the information about Basutti's "methodology" and the "use with caution" notation came from (somewhere else here?), but it is terribly improper to present this as factual/credible -- and with no notation whatsoever about its shortcomings/limitations. deeceevoice 07:19, 2 July 2006 (UTC)[reply]

User:FrankWSweet's website that I added to External Links on 6 Dec has discussion of the Biasutti map, its faults, and a couple of updated maps. I don't know the copyright status of the updated maps. Frank did not change the map in the article when he later showed up on Wikipedia; not sure if he didn't notice it, didn't think it was wrong enough to be significant, or if copyright status wasn't sufficient.

answers.com is a Wikipedia mirror and not citable as a non-Wikipedia source. The Wikipedia link for that image is: File:Map of skin hue equi.png which is exactly the image that was referenced by the article, and in the image page's history (not the file history) you can see User:Dbachmann added those cautions. --JWB 13:30, 2 July 2006 (UTC)[reply]

---

The image that was removed in this edit should be restored. The image is a good one.

An example of the raw data underlying the patterns that the image summarizes can be found in Prof. Jablonski's article, for example.
1. Those making the measurements of skin color tried to select only subjects whose ancestors had lived in the same general area for thousands of years--thus, minimizing the effects of moving to a different geographical area.
2. What is measured is underarm skin color where there is minimum tanning.
3. Underarm skin color is measured by an optical instrument that measures the percentage of light of a standard color that the subject's underarm skin reflects to the standardized photocell. The underarm skin of the whitest person in the sample reflected less than 70% of the incident light.
4. Underarm skin color correlates, not with latitude, but with the annual intensity of UV radiation striking the ground where people live.
5. Hence, for example, looking along the equator, one sees that skin color is lighter around the Amazon basin where most sunlight is blocked from striking the ground where people live--by both high vegetation and cloud cover.
Furthermore, as JWB notes above, the "use with caution" at [4] means nothing to us on Wikipedia because that site merely copied the "use with caution" that has been on Wikipedia for a long time.
As with any image, it would be good to develop a fifth approximation that fits all the recent data better. But let's not throw out the very good first approximation that the deleted image is!

That any reader has the response "That can't possible be right" is appropriate. Many people do not know that the image is basically right. --Rednblu 16:48, 2 July 2006 (UTC)[reply]

Well, Rednblu, because I know I don't know everything, I googled the map before deleting it. What caused me immediately to be skeptical of the map are two things: the 1) the shading for Lower Egypt is the same as for Saudi Arabia and portions of the Maghreb, 2) and it is also the same for the area occupied by South Africa and Namibia. This calls into question the population samples utilized in the map's preparation (if not Biasutti's fundamental powers of reasoning). Did Biasutti leave Egypt's major cities (where the majority of Arabs are concentrated) and examine the true Egyptians? The peasants? Highly doubtful. The Fellahin as a group are quite swarthy and downright obviously Negroid-looking the farther south one travels. The map refers to "native" populations, and the methodology stated above maintains the subject populations had lived in the areas for "thousands of years." Um, 'scuse me. But that might work for someone with an "I'm doin' the the elitist tourist route 'cuz I don't wanna get my hands dirty" approach for the Arab and Arabized populations in Lower Egypt's major cities, since the Arabs overran the area in the 7th century A.D. But how on earth can one say that with a straight face about South Africa? The Boers didn't get there until 400 years before Biasutti did, and I haven't gone around sniffin' up under people's armpits, but I've never met an indigene from South Africa who was as fair-skinned as an Italian. Anyone? (How 'bout you Rednblu?) Even if you want to quibble about Lower Egypt, the South Africa/Namibia representation is glaringly inaccurate, not to mention mind-blowingly counterintuitive. I can't even begin to rationalize how he came up with a Maghreb/Arab skin tone for, say, the Xhosa, Zulu or Ndebele of the region. Even if Biasutti lazily decided not to examine the native populations and simply fudge the data there as he did with the northern Maghreb, it makes no earthly sense.

It seems to me that Biasutti not only took the tourist route and didn't bother getting out into the countryside in Egypt, but he also failed to venture beyond the Boer and European-controlled areas in South Africa/Namibia. This is somewhat understandable. Many are reluctant to sacrifice creature comforts for the sake of knowledge. Sill, I'm puzzled. It seems to me not even a staunch supporter of the racist Boer regime would dare claim with a straight face that Europeans had been there since ancient times. Such a bald-faced absurdity then would call into question the integrity of the entire effort. Yet Biasutti has done so. And even more mind-blowing, his b.s. seems to have gone right over people's heads.

I mean am I missing something here? ~~What are you white folks thinking?~~ Have I lost my mind? Someone (anyone? how 'bout you, Rednblu?) wanna try explaining to me how I'm wrong -- because I "do not know that the image is basically right"? deeceevoice 17:46, 2 July 2006 (UTC)[reply]

No such thing as black skin mutation

To do a section on "The origins of black skin" is backward it should be "The origins of white skin".The article misstates the fact that the mutation is from dark skin and kinky hair to white skin and straight hair,the first humans were black. the mutation is of the other races.

The skin of the chimpanzee, beneath their hair, is white --JPotter 19:47, 12 October 2005 (UTC)[reply]

Assuming that ancient humans and chimpanzees had the same skin color, the genes for darker skin would have to be a mutation.

Cameron Nedland 03:33, 29 December 2005 (UTC) Vehgah Not all chimps have "white" skin [http://www.abc.net.au/science/news/img/chimpanzee.jpg[reply]

link]

All of them except Bonobos.

--65.188.253.47 21:22, 27 December 2005 (UTC)[reply]

Rev. Moon quote

Why is there a quote by Sun Myung Moon in the article? it seems totally random and doesn't belong, there are many quotes about skin color out there, why should this be included in the article? I'm removing it, unless someone can offer a valid reason to keep it.--Kewp (t) 20:35, 11 October 2005 (UTC)[reply]

your skins is ugly

CONTRADICTION

This article says that skin color is determined by a set of genes. Later, it says women have lighter skin than men. Since the genes are the same whether the person is male or female, the article contradicts itself, or at the very least, leaves out an additional determinant for skin color besides genes, one which is tied into gender.

Um, "gender" is "tied" to genes. JPotter 15:35, 1 July 2006 (UTC)[reply]