Recently I saw a TV film about romans. While a few if not all of the main actors resembled italians I remember noticing something really odd about the crouds. The people were very non italian or southern euro looking even though the women did their best to hide their features with headscarves. I was completely distracted. Finally after 10 minutes it dawned on me: to save money the production had taken place in Tunisia. It was really wierd to see ancient Rome populated by desert dwellers with telltale facial features.

Can someone explain the genetics of skin color? Why isn't it like eye color, with one dominant color taking over?

I've noticed this too.

The British seem to have a general desire to usurp the Classical Roman world in their own image - at least in the English speaking world.

But regarding sibs: African-American families can have quite a range of skin tones. Look at the families of people like the comedian Sinbad.

People forget that although on average, individuals inherit 25% of their genes from each grandparent, this can range from 15-35%. So if the grandparents are from different backgrounds, sibs can look quite different, and actually share comparatively few genes. And consequently look rather different. This effect is simply not too apparent where families are relatively homogeneous.

"But regarding sibs: African-American families can have quite a range of skin tones. Look at the families of people like the comedian Sinbad. "

Full-sibs or half-sibs? For polygenic traits like skin colour the frequency distribution among full-sibs will approximate to Gaussian - admittedly not very closely if the number of genes is small. I think it is usually said there are about 5 main loci for skin colour, but I haven't checked.

Can someone explain the genetics of skin color? Why isn't it like eye color, with one dominant color taking over?

see here.

1) skin color is polygenic.
2) eye color is probably polygenic too i would bet (the 'dominant' vs. 'recessive' canard is problematic since there are many shades of brown and blue, as well as green and hazel, etc. etc.), though the primary locus controlling it seems to be different than skin color.

re: naveen andrews, kerala is 20% christian because of an old population of 'syrians' who often have non-indian last names (thomas, joseph, john, etc.). since andrew is a christian saint, it seems possible that that is a syrian christian name.

Three thoughts inspired by this post:

was under the impression that only two or three (Theo, Vanessa, and Rudy, I would guess, if we go by skin color) of the kids on the Cosby show were Heathcliffe and Claire's, and that the others were relatives, or something. At least, I thought I heard that someplace, although I might be mistaken.

I also remember an episode of Law & Order where a black man who could pass for white had a baby with a blonde, blue-eyed white woman and the baby was obviously part black. I thought at the time that it did not make a whole lot of sense.

I also wanted to point out that I found it irritating in the novelizations of the two X-Men movies Storm is referred to as "ebony-skinned" or in some other way the darkness of her skin is emphasized, as the actress playing her (Halle Berry) is cafe-au-lait (personally, I wish they had cast a Grace Jones-lookalike; Storm should look a little scary, in my opinion).

In Heinlein's "Time Enough For Love" the main character (male) clones two identical twin sisters using microcellular surgery to delete the Y chromosome and duplicate his X chromosome.

Brucebo

For me the movie that really took the biscuit, was "Robin Hood: Prince of Thieves", where there is an additional character called Azeem introduced, who is a Moor, but is played by African American actor Morgan Freeman, who is not Moorish looking. Not only is Azeem a devout muslim, but is also part scholar, philosopher and scientist - bringing with him optics and gunpowder technology generations ahead of its time!!!

Based on my own family history, I would have to say that the example of Anthony Hopkins in The Human Stain is actually very plausible. My mother, although identifying herself as African American, would NEVER be mistake for white (she has always been identified as white on traffic tickets and hospital admissions), but she definitely has black ancestry. My mother's uncle moved away from his home town and actually "passed" for white himself, even marrying a "real" white woman, who didn't discover the truth until she met his brother, sometime after they married.

On the subject of Rome (or at least HBO's version) I keep noticing how physically well-matched the actors playing Octavian and Octavia are in playing bother and sister. They also favor the actress who plays their mother - Polly Walker.

"was under the impression that only two or three (Theo, Vanessa, and Rudy, I would guess, if we go by skin color) of the kids on the Cosby show were Heathcliffe and Claire's, and that the others were relatives, or something. At least, I thought I heard that someplace, although I might be mistaken."

- I'm no expert on the Cosby Show (though I enjoyed it) but according to a website source the Huxtables had 5 children (one son and four daughters). You may be thinking of the little girl (played by Raven Simone), who was supposed to be a cousin or something, who joined the cast in the last series or two. If you use Google Image search you'll find various photos of the 'family'. I would guess that the 'children' were deliberately chosen to cover a wide range of skin colour. The two oldest daughters, played by Sabrina LeBeauf and Lisa Bonet, were much lighter than their 'parents'. Lisa Bonet is definitely mixed-race, with a white mother. I don't know about Sabrina, but her ancestry looks predominantly white. I think it would be highly improbable for parents as dark as the Huxtables to produce two daughters as light as Lisa and Sabrina. Bill Cosby is very dark, so they would need to get all the 'light' genes from their mid-brown mother.

I'm sure Anon is right that people with some African ancestry can 'pass for white', because they *are* white! I wouldn't count anyone with less than 1/8 African ancestry as being 'black'. It is only under the preposterous 'one drop' definition that some people self-style themselves as black.

"re: naveen andrews, kerala is 20% christian because of an old population of 'syrians' who often have non-indian last names (thomas, joseph, john, etc.). since andrew is a christian saint, it seems possible that that is a syrian christian name"

- Razib: I had forgotten about the Kerala Syrian Christians. Don't they feature in that book by Arundati Roy (spelling??), or am I mixing them up with something else? I don't know if Naveen Andrews comes from this community. His father's name (Stanley Andrews) sounds Anglo-Indian to me - I doubt that there are many Syrian Christians called Stanley! But Naveen and Nirmala (his mother's name) are Indian names, so maybe there is intermarriage between Anglo-Indians and other Christians in Kerala.

Don't they feature in that book by Arundati Roy

her mother is from that community.

so maybe there is intermarriage between Anglo-Indians and other Christians in Kerala.

intermarriage between anglo-indians and indian christians is relatively common from what i gather (relatively remember). naveen andrews regularly plays anglo-indians, but he defintely looks "browner" than typical.

Charlie Kaufman's Adaptation has identical twin characters with opposite personalities. I will grant that this is not a clanger in the same league as a guy with an "identical twin sister".

pconroy: "a Moor, but is played by African American actor Morgan Freeman". On those grounds, isn't it rather odd that it has become almost compulsory for The Moor of Venice to be played by black men? Or has Will's play half-persuaded the world that Moors are black men?

On those grounds, isn't it rather odd that it has become almost compulsory for The Moor of Venice to be played by black men? Or has Will's play half-persuaded the world that Moors are black men?

in the USA anyone who is from africa is tentatively allowed to be black. it's a function of particular sociocultural dynamics. i remember seeing hannibal listed as a 'great black man' in a afrocentric history book once. st. augustine (of hippo) too. the same tendency is exhibited in the characteristic of eliding over the difference in coloration and features amongst black people so that they are all once solid "of color" block. there is a one-drop essence of blackness. this was originally of course a racist truth, but for the sake of numbers and solidarity the black cultural elite has picked it up. i remember a few years ago oprah asked tiger woods how he felt that when people see him they see a black man. but of course, she was projecting her own ascertainment bias, many asians see someone with asian features. but the white cultural elite tends to defer to blacks on this issue, especially those based out of the east coast cities where the 'race problem' is still predominantly a black-white issue.

p.s. on a bizarre note, i remember shelby steele, the half-white black conservative, joking how funny it was that his 3/4 white children often got strange looks at black churches that they attended. but of course they get strange looks if they look white, though steele noted his children 'identified' as african american. the importance here, as glenn loury noted in attacks on steele, is that his children have to make a proactive effort to identify and don't really deal with the 'black experience' on a day to day level.

Spiderman gets bit by an insect. The Hulk gets dosed with a "gamma ray". The Fantastic Four take a bath in "cosmic rays". Much of Stan Lee's bioscience of superheros is less than kosher, something that Lee himself cheerfully admits is a "gimmick". Chalk these up to suspended disbelief and call it fair game.

in the USA anyone who is from africa is tentatively allowed to be black

In Dark Star Safari Paul Theroux finds himself reminding others that Egypt is in Africa ... even while he is in Egypt. People evidently conflate blackness with Africa and vice versa.

Sir Anthony Hopkins is the laziest actor in the whole world. He has never mastered an American accent (remember "Nixon"), so in "The Human Stain" he's supposed to be an African-American guy passing as a Jewish guy from New Jersey who somehow has a British accent. And he didn't put on any makeup to look a tiny bit black either.

In contrast, the actor who plays his character as a young man (the star of "Prison Break") is nearly perfectly cast, and turns in a better performance than Sir Anthony.

David B:
"I'm sure Anon is right that people with some African ancestry can 'pass for white', because they *are* white! I wouldn't count anyone with less than 1/8 African ancestry as being 'black'."

As a white person, you are less likely to be aware of the range of colors african americans come in. If you see a black person who "passes" as white on the street, you see them as white so you won't make the mental connection. African Americans however always seem to have one random white looking relative who isn't really white, hence, they tend to pay more attention to facial features as well. Since coming to the US, I've spent a lot of time around african americans and have become very attuned to picking out features beyond just pale skin, since I've learned that this can be an incomplete signifier of race. I've had a couple of half white half black friends who are often mistaken for white. I have even more quarter black friends who might as well be white.
For example, here's a picture of Victoria Rowell's daughter. Victoria is half white, and half black. Her daughter has a white father and looks whiter than many whites I know.
http://www.mahoganycafe.com/ladi...m/ ladies16.html.

In my experience, most people who are 3/4 white, 1/4 black can pass as white. See also Sailer's article about the white professor of genetics who discovered he was 22% black.
http://www.upi.com/view.cfm?Stor...02-084051- 5356r

I still think the worst science mistake ever made in the history of cinema was in Red Planet where one of the cast speaks of the four bases in DNA as being 'C, A, T and P'... I mean, come on, how much research is required to figure out that that's a blunder?

Star Trek Voyager, Season 2: Threshold. (http://www.st-hypertext.com/voy-2/threshold.html)

Janeway and Paris, due to some warp accident have their DNA changed and consequently *devolve* over the rest of the episode, turning into newts. That's wrong on so many levels.

BTW, 'Syrian' Christians in South India are not descended from Syrians, any more than Roman Catholics are descended from Romans. 'Syrian' refers to the rites and doctrines of the Syrian Church, which is one of the most ancient in existence.

It's clear from the text of Othello that Shakespeare intends for the character to be black (thus, "an old black ram is tupping your white ewe" and "What a full fortune does the thick-lips owe..."; and "...Would ever have, t'incur a general mock / Run from her guardage to the sooty bosom / Of such a thing as thou?"). Thus, it isn't odd that the role is cast that way.

Anon: Thanks for the interesting links. I agree that Victoria Rowell's daughter looks entirely 'white'. If Victoria is 1/2 black her daughter is 1/4 black, so it is a bit surprising if there is no sign of black ancestry at all. But maybe Victoria is really more than 1/2 white - her 'black' parent may already be part-white. On average, American 'blacks' have 20% or so of white ancestry, and often more than this.

As regular readers will know, I am not American, so forgive me if I don't always understand American sensitivities. I live in a racially mixed part of England, where there is a lot of interracial mating, and a walk round the local supermarket will show a huge range of different colours and combinations (including black-Asian). Based on my own casual observations, someone who is 3/4 white (British or Irish) and 1/4 black (Caribbean) will usually still have some noticeable 'black' traits, but in English usage they would not be described simply as 'black'. Someone with only 1/8 black ancestry will usually look 'white', but on close inspection you may *suspect* a trace of black ancestry. E.g. the hair may be a bit crinkly.

Besides Othello, another famous Moor in Western culture is Monostatus in Mozart's Zauberflöte (The Magic Flute), who is clearly Black.

German Wikipedia has a better Moor article than English has, you can go there just for the pictures of some moors, for example in old sigils or the current Pope's. http://de.wikipedia.org/wiki/Mohr.

In old English usage 'Moor' is a pretty vague term. I assume that 'Blackamoor' is related to it.

Sir Anthony Hopkins is the laziest actor in the whole world. He has never mastered an American accent

Hmmm, well, Hopkins has mastered several different modes of speaking, outside of mere accent. And remember, in acting there is an informal rule: if you cannot do an accent very well, then do not attempt it at all. Considering this, and considering that most people have difficultly mastering accents, is it any wonder that he just goes ahead with his English accent?

And this issue of Othello, Arabs, Jews, and Blacks were very rare in Shakespeare's England so an audience of that time (usually a poor, working class audience) would not have the sophistication to tell the difference and would have just 'lumped' them all into the "dark other"

Finally this complaint about entertainment and their use of science while an interesting topic, is a bit fruitless. These people are in the business of entertaining the general populace, most of whom don't even understand or care about the basics of science they learned in High school.

"I agree that Victoria Rowell's daughter looks entirely 'white'. If Victoria is 1/2 black her daughter is 1/4 black, so it is a bit surprising if there is no sign of black ancestry at all. But maybe Victoria is really more than 1/2 white - her 'black' parent may already be part-white. On average, American 'blacks' have 20% or so of white ancestry, and often more than this."

Victoria Rowell also looks as if she might have some East Asian ancestry.

Another movie that deserves an award for genetically ignorant casting is 1994's Rapa Nui. As its name indicates, it was set on Easter Island and its characters were supposed to be ethnically Polynesian. Instead, its main stars were Esai Morales (Carribean Hispanic, probably Puerto Rican or Dominican, and therefore mulatto); Sandrine Holt (Chinese/English mixture, who had played an American Indian in a prior movie); and Jason Scott Lee (Chinese and Hawaiian, I suppose the Hawaiian part was okay for the role).

Peter,

You expect too much. The first problem in casting a film on Easter Island is finding enough polynesians with enough talent (and box office draw), a tall order that one. The second problem is that most people would not know or care that the cast was not polynesian, and only care that they had yellowish-brownish skin color.

As someone else mentioned, different people look for different things as racial indexes. Whites define themselves by color, and look primarily for this. But race is not only defined by Whites.

Many African-Americans have a very sensitive eye for any traces of blackness. They also notice things like voice quality (not accent) that whites tend to be blind to. Other give aways can be body type, subtleties of bone structure, hair type, distribution of body fat, etc.

"The British seem to have a general desire to usurp the Classical Roman world in their own image - at least in the English speaking world."

They don't really need to "usurp" it exactly, even if many Italians do have a distinctive look. A striking number of characters in Victorian novels are described as "Roman nosed" and "dark complected" and they are generally not supposed to be of foreign orign.
The Romans were in Britain for centuries, and many an Anglo ended up in Roman slave markets as seen by Pope Gregory the Great, c. 400s A.D., who decided once and for all to convert them. That is also why those seemingly bizaar tales of Jesus' relatives and followers ending up in Albion are not so weird--plenty of merchants, traders, etc., from the Levantine coast were known to be in what we now call the British Isles, as this was all part of the Empire connected by an extensive network of excellent roads. The Arthurian legends date back at least that far and contain elements related to Classical mythology, including that of the near east. We don't really have to use too much imaginiation as to what the Romans looked like. Their busts and mosaics crowd museums and ruins and picture books. Their looks varied from light to dark, just as they do today, especially in the middle area of Italy.

DavidB wrote:
'Syrian' refers to the rites and doctrines of the Syrian Church, which is one of the most ancient in existence.

Syrian, Coptic and Armenian Christians are more loosely termed Monophysites.

Not to be confused with Assyrian Christians, who are often referred to as Nestorians.

Well, it came as quite a shock to the idiot in the "Jerk" when he learned he was not their natural child. After a bit of weeping, he had to admit he always knew it--the Blues depressed him so much.

And poor Victoria Rowell's daughter, whatshername--she's going to be a conversation piece among strangers all her life, what with genetics being more and more discussed.
Oh well. Ms. Rowell encouraged this by appearing on some talk show years ago, with her blond 3 year old in tow. The theme of the show was, black women with white looking kids. VR's kid may look exactly like her dad, but she may also look like her mom's mom who was white. Isn't that what recessive means? A person may look quite dark but maybe one of their parents had Paltrow coloring. It is logical to assume that these very white looking "black" kids do have that sort of immediate background in most cases. There's an earlier celebrity mom-daughter, unlikey duo. Eartha Kitt (white father, black mother) had a white husband and a white looking daughter. That girl looked like Alice in Wonderland, long blond hair (natural, not Beyonce type), and quite white. There is no way you would have thought "black."
There is a theory that the extremely non-black looks of many "mulattos" disturbed the northern abolitionists so much, because they saw these people as white. It disturbed the southerners because they saw them as sort of "black" but deceptive in spite of themselves.

The "one drop" rule is of fairly recent vintage, perhaps turn of the 19th century. In the 1900 census, people who were always described as "mulatto" in earlier censuses were suddenly marked as "black." That began an exodus from the South by these "black" white people (or white black people.) They left the black designation behind.
It made it easier for whites, not having to worry about "are they" or "aren't they." It was a boon for blacks, taking the racial question mark out their lives and increasing their numbers, while allowing them to legitimately claim as "black achievement", the accomplishments of people who would never be considered black anywhere else in the world.
Prior to the civil war, a person could claim to be legally white if less than 1/8 black. Eventually, how this played out in the rural/small town South in later decades, where lineage could be a noose, gave William Faulkner endless grist for his story mill.

I can't agree with Scott about Othello. In contrast with moderns, the English of Shakespeare's day (and even of the last century) were fascinated by racial and ethnic differences (particularly among Europeans, naturally, but also outside). The Jew Shylock is portrayed as grasping, parsimonious, as concerned about his ducats as his daughter; the black Moor Othello is portrayed as sensuous, hot-blooded, and superstitious - you wouldn't dream of seeing either character given the other's race, not in Shakespeare.

He was too great an artist to draw them shallow, but too much a man of his times to ignore the differences as he saw them. Maybe he went too far that way, and doubtless modern artists are going way too far the other way, but perhaps the next century will bring a better balance. (Though methinks things will have to change a lot before Hollywood ever remakes The Bad Seed...).

NuSapiens wrote:
They also notice things like voice quality (not accent) that whites tend to be blind to. Other give aways can be body type, subtleties of bone structure, hair type, distribution of body fat, etc.

IMO most White people notice these things also, I certainly do. For instance take Vin Diesel - who is reputedly of Black and Italian descent, when he speaks he voice sounds somewhat Black in timbre.

everyone, note the tendency to see what you are looking for. i suspect that anyone who is 1/8 black is basically white, and their "black" features are things that might intersect with african features, but are probably due to looking for something that might "fit."

razib wrote:
"On a more mundane level, we often see blue-eyed screen couples with brown-eyed children,"


Chelsea Clinton is brown-eyed, though Bill and Hillary Clinton have blue eyes.

[i didn't write that, david b did -r]

Edited By Siteowner

"Chelsea Clinton is brown-eyed, though Bill and Hillary Clinton have blue eyes."

Before revising genetic theory, check the facts. I just searched Google Image for Chelsea Clinton, and her eyes look blue to me!

everyone, note the tendency to see what you are looking for. i suspect that anyone who is 1/8 black is basically white, and their "black" features are things that might intersect with african features, but are probably due to looking for something that might "fit."

But isn't that what the mind does automatically when determining race? It takes individual features and based on probability of occurence, categorizes into a racial group.
People determine this probability based upon their personal experience with those they associate with most. And since whites mostly associate with other whites (relatively), a white person needs a lot lower threshold to determine race. Light skin, skinny nose, and straight hair will do. However, to african americans, who average 20% admixture, the threshold will need to be higher.
So I don't think people are necessarily looking for features, more than some people instantly recognize features others don't based on the need to do so. This is similar to the cross-race effect which is defined as the tendency for members of a group to look alike to members of another group. For example, it took me forever to be able to see a hint of difference between Koreans and Chinese, however, a period of time spent around many Asians added to my threshold for determination.

ina,

my point was that on a checklist of "white" and "black" features (pick an arbitrary, but reasonable, list, doesn't matter) very few blacks or whites will match every aspect of that list. most of the time that is irrelevant, the other aspects give you enough information to determine their race. but, if you say "so and so is 1/8 black" i think there is a tendency to simple assume that features x, y, z... which might not be modal for whites is due to the black ancestry. but i think a lot of the time it is just due to the noise around the "ideal" white phenotype.

an analogy is the experience i know of many adoptees being told they look like their mother or father when the person doesn't know that those aren't their biological parents. human beings look similar to some extent, so if you know the features should match you find a match.

David B wrote:
Before revising genetic theory, check the facts. I just searched Google Image for Chelsea Clinton, and her eyes look blue to me!

I don't think you have to revise genetic theory--the single-gene model of eye color inheritance that gets taught in introductions to genetics is not accurate, as razib pointed out earlier it's actually polygenic. This page from about.com says:

"However, blue-eyed parents can have brown-eyed children, although genetic processes for that possibility aren’t at this time well understood."

Also see this page, which explains the three known genes involved in eye color, and mentions that

"there are reports of blue eyed parents producing brown eyed children (which the three known genes can't easily explain [mutations, modifier genes that supress brown, and additional brown genes are all potential explanations])."

Oh, and here is another page on the subject of blue-eyed parents and brown-eyed children, written by a geneticist, which says it could be explained either in terms of something called "genetic compensation", or in terms of recombination, or in terms of environmental influences on gene expression.

Jesse: thanks for the interesting links.

As far as I can see, the proposed genetic explanations of blue-eyed parents having brown-eyed children are entirely speculative and unproven. So far as *established* genetics is concerned, this phenomenon is not explicable except by a new mutation.

In view of the relatively high frequency of false paternity (at least 1% in modern societies), this possibility should always be excluded before resorting to new genetic theories.

"But don't let this put you off watching it!"

Well, no, the genetic issues didn't put me off watching it. Your unnecessarily giving away the ending is what put me off watching it.

There was no need to do that. I was intrigued by the film - and the related issues you brought up in the post - until I found out how it ended. Was this necessary to include in order to preserve the integrity of the discussion? I don't see how it was.

I'd like to point out that the number of genes responsible for a distribution is equal to k*(mean/std dev)^2. Let us take an elementary example. Toss 64 coins 1000 times and plot the relative frequency of the number of heads. It will be a bell shaped curve. Mean 32 std dev 4.
N=(32/4)^2=64. Of course this is trite. But assume that a head means an intelligence gene is there and tails that it is not there and you have the basis of the calculation. Genes will not occur with probability 1/2 nor will contribute equally hence the factor k. Now for blacks mean=85 and std dev varies from 11 to 14 (say it is 12.5).thus mean/std dev =6.8 whereas for whites mean=100 and std dev = 15 giving mean/std dev =6.67 (approximately the same. Contact me for a detailed calculation of k.

Ned: sorry about the 'spoiler'.

Philip: I'll have to think about that. Presumably environmental and non-additive genetic effects would mess up the picture. I doubt that there are only ~7 genes (or loci) involved in genetic IQ differences.

Excuse me! but I indicated (mean/std dev)^2 which would be about 44. Sorry for my interruption but I read an earlier blog with some interest and I would like this point clarified.

Sorry, I overlooked that. I am emailing you with some questions about your approach.

Philip D'Souza: “Excuse me! but I indicated (mean/std dev)^2 which would be about 44.”

Note that 44 is the number of autosomal chromosomes. (I know the calculation method you used isn’t that precise. Still, it is an interesting coincidence.)

My guess is that genes (and chromosomes) would follow a power law distribution for IQ influence. If so, how would that affect your calculation?

I’ve seen family groups (parents and four children) in which the IQ’s differed by over 3 SD’s. My intuition is that such family patterns indicate that a few chromosomes can exert a strong influence on IQ. However I don’t believe any studies looking at correlations of family IQ to genetic markers have found any chromosomal regions that have such strong influence. I suspect the genetics underlying IQ will turn out to be complex with multiple gene interactions playing a significant role.

Fly,

I can attest to vast differences in IQ in one family at least - my own.

Both parents are uneducated, my Dad loathes education and "book learning", my Mom a big advocate of education, but dyslexic, OCD and somewhat autistic herself - so very hard to judge either of their IQ's, but they certainly wouldn't score well on a standardized test, that's for sure. Both come from very high IQ families, who are pretty much all professionals.

Of my 6 siblings, one sister is probably about IQ 95-105, another 2 about 110-115, another one about 120-125, my brother about 135-140, and I'm variously 135-145, except one test where I was 157 - I'm excluding much high results I achieved as a teenager. So I think as much as 4 SD's in difference is possible between siblings.

your comment about the cosby kids make me wonder just how much knowledge you have about african genes. my family are ethiopians from kenya. i have lighter skin than both my parents, my sister is darker than they are and my other sister is even ighter than i am. this is not unique around here, it's the norm. family members almost always never have the exact skin colour, as each other. the range in immediate family members can range from extremely light, to extremely dark. i found nothing unusual in the casting of the cosbys, and i don't think doctor huxtuble needs a parterity test at all! i think it's obtuse to assume one has to resemble the skin colour of a parent. they say i resemble my great grandfather. clearly very liitle genetic study has been done on people of african origin. so, there is the attempt to apply findings of other races and try to fit them to us. obviously, this isn't working. my understanding is that people from east africa have the greatest genetic diversity than anywhere else in the world. perhaps this would be an ideal place to start mapping out how genes work in folks of african origin. frankly, it's suprising to find that folks are debating about such a commonplace occurrence.there are unique instances where a child with one black and one white parent comes out looking completely white, or completely african looking. it's a rare occurrence but, here where such marriages have increased, i have seen this phenomenon a few times. in one case the man demanded a DNA test, and the child ended up being his. the other case it was the mother that looked completely different from her child. she thought the hospital switched the babies, by mistake. DNA test proved that baby was hers as well. i thought that is exactly what the movie 'secrets and lies' was supposed to portray.

i meant to say paternity!

Pconroy,

Yes. However, intelligent people tend to have intelligent friends and associates. So personal experience might lead a bright person with bright friends to conclude that their family IQ distributions were common. I also know there are a few families with exceptional talent. So what percentage of bright people come from exceptional families and what percentage come from average families with an exceptional member?

The distribution of family IQ distributions should indicate whether there are a few strong genetic determiners of IQ or whether there are many small determiners. (I assume people who study this stuff have already modeled the family IQ substructure of the larger population IQ distribution.)

Siti,

I hate to have to tell you this, but the Italians conquered Ethiopia and held it for a time during WWII, and during this period Italian soldiers fathered quite a lot of children with Ethiopian women - one way or another, if you know what I mean.

I knew someone who dated an Italian guy from New Jersey, called Giuseppe, only when she she met his parents did she realize that they were from Ethiopia, but of partial Italian descent.