I was curious why an old Genetics and Health post, Twins with Different Skin Color Genes, was sending me many referrals today. Now I know, Two in a Million: Twins Born - One Black, One White:
The twin boys, named Ryan and Leo, are the offspring of a mixed-race couple.
The mother, Florence, hails from Ghana in western Africa, and dad, Stephan, is from Potsdam in Germany.
"Ryan came first, and everything was as usual," said the hospital's doctor, Birgit Weber. "But when Leo was born, I couldn't believe my eyes."
"Both kids have definitely the same father," the doctor added.
These aren't the first of these "amazing" of twins. I've posted on this sort of story before, Can you tell if you're black or white?, "Black" & white twins again and Ivory & ebony, twins again...and again.... I touched on the major genetic points in depth in those posts, but this case is a bit different since you have two parents who are monoracial; this makes the odds in terms of genotypic combinations a bit confusing. I think that the easiest way to explain the outcomes are stochasticity of gene expression during development, and, possibly gene-gene interactions between these two parents which allow for deviations outside of the expected range. If what I'm saying is unintelligible to you, I recommend you read the posts I linked to above, it will make the context clearer.
At this point I just want to put a slight spotlight about what the doctor said. The "black" baby pops out, and the doctor isn't surprised, the "white" baby pops out the doctor is totally shocked. Why? The father is white. But we know why: black is dominant to white, black + white → black. I'm generally not one to think that racism is the greatest of all evils, so I don't want anyone to take what I'm going to say next as if there's a major value judgment...but I suspect this expectation that many white people have that blackness dominates over whiteness has two roots; a psychological and sociocultural one.
First, deviations from your own population's norm are more salient than from those of the Other. This is a neutral observation. I've talked to Asian people who claim that Eurasians always look more European than Asian, and Europeans who claim the inverse. I suspect this is just a natural function of the fact that people have more attention to detail in regards to their ingroups.
The second factor is the one I don't want people reading too much into,1 but I suspect it is just due to the early 20th century idea that the superior Nordic race's qualities are easily diminished by admixture with Colored races. I think that this is the same factor which drives the continuous reemergence of the blondes going extinct meme. This particular idea actually dates back to the Victorians and has persisted across decades and medium (there have been two internet outbreaks of the blondes-going-extinct meme since I've been blogging!). In our ostensibly post-racial and non-racist era the explicit connotations of superiority have been removed from the equation, but the shadow of the general idea of the potency of Colored blood in wiping away the features of the Nordic race still persist. I get emails from people which imply the persistence of this theme in the general population; e.g., an East Asian woman who is married to a British man was told by her mother-in-law that their children would of course look Asian because "Asian blood is strong." I didn't get the impression that the mother-in-law was racist or objected to the mix-marriage, but this woman, raised in China, was confused because her own childhood folk genetic expectations were not like this at all, she had perceived Eurasians to be very European in appearance. She came to me for some understanding of the major issues in terms of scientific genetics.
In any case, I don't have simple explanations for these sorts of queries. But, I have pointed out that in fact it looks like skin color genes will average out to produce offspring with a complexion closer to that of the lighter skinned parent than the darker skinned one! In other words, when it comes to skin color the folk genetics is just wrong, and the doctor above should really have been more surprised by the "black" twin than the "white" one.
1 - I believe most humans wish to perpetuate the broad outlines of their phenotype into the future. This naturally implies that many white people want features associated with whiteness to persist into the future, and that entails some discomfort with the idea of hybridization. Very few white people are easily candid with me about this sort of thing because I'm colored and they of course assume that I'd get offended, especially if they're aware that I'm pretty much guaranteed of sullying the white gene pool! But even if no one is explicit about it there are cues and hints that suggest that many whites are just as phenotypically conscious privately as people of the colored races are openly; e.g., the way people will talk about blonde hair and blue eyes as especially notable markers of aesthetic virtuosity in children and young adults. These are characteristics of course almost universally of white people, so the implicit signal is pretty obvious about which race exhibits the greatest potential for beauty in the eyes of those who are expressing these sentiments. To give a specific example, on a recent 60 Minutes they profiled the white son of an American deserter in North Korea (his mother was the daughter of a Romanian diplomat). Morley Safer observed that this young man's blue eyes and blonde hair of course made him very popular with the women in North Korea. One could claim that this was simply a nod to the value of exoticism, but just change the context to rural America and a Korean young man, does anyone believe that his black hair and Asian features would make him inevitably attractive to farm girls? :-)
Are you over-egging your pudding here, and perhaps implying a prejudiced mindset that the facts don't support:
Perhaps the doctor was surprised rather than "shocked", and surprised not because the second child was "white", but because it differed so markedly from the first child? Because one generally expects more similarity between twins, and this doctor had seem plenty of twins born.
Surprise isn't always prejudice, our minds naturally form expectations, some based on experience, some - hopefully fewer - on prejudice. I found my mind "hopping" slightly when a girl who was born without a right arm came on the television; I have no prejudice about missing limbs but my visual systems were doing their job of trying complete the expected image by "filling in" the expected right arm as though it were temporarily out of sight, and were flagging up "we can't make sense of this boss!" in the same way as they do with optical illusions.
but I suspect this expectation that many white people have that blackness dominates over whiteness has two roots
Even without the two reasons you list, the biological perception is tinted by hypodescent. Since the baby is assigned socially as black, it is perceived as biologically more black as well.
Public Enemy - Fear of a Black Planet:
Black man, black woman, black baby
White man, white woman, white baby
White man, black woman, black baby
Black man, white woman, black baby
In America, "not totally white" = "black". That's why Barack Obama or Halle Berry are called "black". In France, they'd be called "metis" or something.
Now the "not totally white" character is clearly dominant. If you have just one black parent, the child will usually not look completely white. Thus, the expectation that "black" phenotype is dominant over "white" phenotype is not incorrect, per se: it is a logical consequence of the rather bizarre folk definitions of "black" and "white".
In addition to this, there is the fact that brown-eyes are, indeed, dominant over blue-eyes (or at least that's the over-simplified message that we've all been taught at school).
As for the two kids in this picture, I don't see why you need developmental or epistatic factors to explain the difference. The article doesn't say that these are "true" twins (MZ). If they are DZ twins, why should we be surprised that they differ from each other?
The oversimplification and just plain ignorance of genetic is what "shocks" me. I would say from personal experience with my own "black/white twins" that eye color and hair color/texture cause even more dumb comments than skin.
My eyes, skin, and kinky hair are brown and my white husband's eyes are green. Nobody in the last 4 generations of his European-origin family have blue eyes or other Nordic features.
So how did we have a blue-eyed, blonde haired twin and one with brown skin-hair-eyes? In the US, the assumption is that the "Nordic" one is a "throw back" from slavery times or some far reaches of the white side.
Uh, not so far back as it turns out. My Nordic son simply looks like my Irish mother who had blue eyes and straight blonde hair.
So we got one of each "race". So much for blonde extinction!
Razib,
Couldn't the father just be a rare SLC24A5 heterozygote? That could explain the two phenotypes.
Perhaps the doctor was surprised rather than "shocked", and surprised not because the second child was "white", but because it differed so markedly from the first child? Because one generally expects more similarity between twins, and this doctor had seem plenty of twins born.
retarded doctor then. most twins are DZ, so stupid expectation.
Surprise isn't always prejudice, our minds naturally form expectations, some based on experience, some - hopefully fewer - on prejudice.
the line between "prejudice" and "expectation" is minimal. there's a value judgment to the former that there isn't to the latter. i also think racism and prejudice are very common and nearly universal. educated white people have been socially conditioned to much more polite than non-whites have, but i don't think all race sentiment has disappeared (this is less of an issue for higher IQ nerds, but most people aren't high IQ nerds).
Even without the two reasons you list, the biological perception is tinted by hypodescent. Since the baby is assigned socially as black, it is perceived as biologically more black as well.
hypodescent is predicated on inferiority in this context (there are cases where hypodescent goes to the higher status parent, but not this case historically).
The article doesn't say that these are "true" twins (MZ). If they are DZ twins, why should we be surprised that they differ from each other?
this is addressed in my other post. but about 4 genes can account for 90% of the between population difference. on the other hand, africans and europeans are *disjoint* or nearly so on several of these genes:
SLC24A5
SLC45A2
the main in the photo has blue eyes. so likely OCA2 and possibly KITLG.
when you have a black african parent crossed with a northern european there shouldn't be much variance from the expectation due to the genetic architecture. OTOH, if both parents are biracial the possibilites for variance are high since both parents will be heterozygotes on each loci. get it?
Couldn't the father just be a rare SLC24A5 heterozygote? That could explain the two phenotypes.
he has blue eyes and fair skin. has a european been found with SLC24A5? that's the second most ancestrally informative marker for europeans! also, if you look at the recent european pigmentation papers the LODs for things like blue eyes and fair skin are really high for SLC24A5, doesn't look like his phenotype fits. the small minority of europeans who carry functional SLC45A2 are generally olive skinned, and we know that SLC24A5 accounts for around 1/3 of between population difference. if he's a heterozygote he should be about 20% swarthier than the northern european norm (mild dominance for lightness). long way of saying that i think misattributed paternity is more likely than SLC24A5 (not saying it is impossible, just less likely these individuals are so rare).
btw sam, to be clear i don't think our models are exclusive. additionally, even if i'm wrong in what i'm imputing to this doctor i think the general point holds as to why these stories get really popular.
That works for me, though the caveat that follows seems relevant for that particular case.
I think "racial blending" will continue to lead to beautiful populations, and I look to Brazil as a hint of that future.
However, it's also arresting to notice unconventional beauty found in extreme phenotypes - extremely dark or light skin, hair, and eyes, extremely Nordic or Asian or African features, etc. (I wish there were more precise terms for what I mean). Beauty is often described as consisting of symmetry, sexual dimorphism, and averageness. But that averageness is sometimes overrated, and beauty that is absolutely not average is compelling.
I think that's the non-racist rationalization for the interest in the "blondes going extinct" BS. I'm glad to have people pointing out that "racial" interbreeding will not eliminate extreme phenotypes. It may make some of them more rare, but it may also match extremes from separate populations in some fascinating ways.
I think "racial blending" will continue to lead to beautiful populations, and I look to Brazil as a hint of that future.
i suspect that it is mostly a wash. very close inbreeding is problematic, but i think you get most of the marginal return by the time you hit 2nd cousin anyhow. there are issues with masking deleterious alleles, but i think that's balanced by genetic incompatibilities (this crops up most in mother-fetus conflicts).
However, it's also arresting to notice unconventional beauty found in extreme phenotypes
i think if you take the logic to its conclusion you note that increase variance does not necessarily change the expectation. IOW, extreme phenotypes may be both the most attractive and least depending on the combination.
Beauty is often described as consisting of symmetry, sexual dimorphism, and averageness. But that averageness is sometimes overrated, and beauty that is absolutely not average is compelling.
i think there are a few orthogonal components to 'beauty.' symmetry/averageness explains the greatest amount of the variation i think, but sex-specific secondary sexual characteristic exaggeration is probably right behind. the other stuff is more subjective (some people like blonde hair, and some do not, and so on).
I'm glad to have people pointing out that "racial" interbreeding will not eliminate extreme phenotypes. It may make some of them more rare, but it may also match extremes from separate populations in some fascinating ways.
the theoretical range of variation should not decrease; you're right that some particular genotypic combinations will be rarer in random mating (and since populations may be small some individuals will not be realized in all generations). but as you note, novel previously unknown combinations will also emerge. part of the background problem is the fallacy of 'blending genetics' which is the common sense way that people think of these sorts of things.
I'm a little confused here - my reaction would be the opposite of the doctor's - should the surprise be at the darker twin, not the lighter one??
I would have to suspect non-paternity of the darker twin.
I would have to suspect non-paternity of the darker twin.
yes. normally babies are much lighter than their adult complexion. this could be a multiple paternity twinning....
Don't know why people are amazed about all this. I'm half Cherokee, half Dutch. So is my brother. I have blonde hair blue eyes fair skin and short and pudgy. He's 6'6" tall, green eyes, black wavy hair and skinny as hell. He was raised up north, and I was raised in Texas. He's dumber than a stump and totally useless. I'm freaking brilliant and put many people who move to Texas in their place as far as intelligence goes. I can win any intellectual argument with these northern dupes. Must be the cold.
And yet in Australia the plan was to "breed the black out" by marrying half-aboriginals to whites. They thought it would take 5-6 generations of breeding back to whites (see wikipedia overview). So not everyone thinks black trumps white.
They thought it would take 5-6 generations of breeding back to whites (see wikipedia overview). So not everyone thinks black trumps white.
if it's 5 generations of outbreeding that's 1/32, right? don't you think that implies the potency of "black blood"? in any case, the physical anthropology i've read suggests that most people who are 1/4 oz aboriginal can "pass" as white; unlike africans and melanesians aboriginals don't normally have kinky hair, so the hair form is not a give away. additionally abos of the deep desert are often blonde.
Razib, interesting post. I haven't read your linked posts, or the other links, or any of the comments. However: in the black-white context, skin color is not the only perceived marker of difference - it is also hair type, inter-pupillary distance, nose shape, ear size, etc. We all know people who are called, and thought of, as 'black', even though they are quite light-skinned, and could 'pass' if that were ever the only criterion. I wonder if you have insights on why things like nose shape, far more often than not, seem to turn out to reflect only the one stereotypical phenotype? How could traits like that be 'dominant', and if they could, why would they be dominant? Or is that just a prejudiced perceoption?
How could traits like that be 'dominant', and if they could, why would they be dominant? Or is that just a prejudiced perceoption?
it's the binning that toto is referring to. for example, children who are of mixed parentage often have hair form that is very curly, but not as tightly curled as their black parents' hair. but it is binned as "curly," and curly is dominant. the curliness of hair is determined in large part by the shape of the follicle, and i'm assuming that biracial kids have follicles of in-between character.
i'm focusing on skin color cuz:
1) biggest organ, so it looms large in any phenotypic categorization
2) babies don't have well defined features (many african babies are born with straight hair which "naps out" over time)
Isn't this a bit contradictory to your statements above... if it's about preserving your own phenotypic outline, why are Koreans attracted to blue eyes?
Change the context to Finland: I don't know how a Korean would fare (I've seen some half-Vietnamese do pretty well) but the attractiveness of dark eyes and hair to Finnish females is a byword...
(Of course some ethnicities are perceived as 'sexier' than others, exemplified by a recent Swedish teen movie of an Iranian boy pretending to be Italian to impress girls)
if it's about preserving your own phenotypic outline, why are Koreans attracted to blue eyes?
i suspect a lot of this was safer's expectation of why this kid would be popular, not necessarily the reality. but some of it in the asian case has to do with the fact that european features are now considered attractive in much of east asia (they weren't before) because whites have been the master race for a few centuries. classic examples of this phenomena are the popularity of eyelid surgery and browning of the hair when the distinctive epicanthic fold and black hair were seen as marks of beauty when east asians were culturally more confident (brown haired japanese women would dye their hair black, now black haired japanese women get brown highlights)
I don't know how a Korean would fare (I've seen some half-Vietnamese do pretty well) but the attractiveness of dark eyes and hair to Finnish females is a byword...
yeah. i've heard this. but there is a fair amount of social science research in the USA that women are much more racially conscious than men when it comes to hittin' it, so i'd like to see some quantitative data on these trends.
yeah. i've heard this. but there is a fair amount of social science research in the USA that women are much more racially conscious than men when it comes to hittin' it, so i'd like to see some quantitative data on these trends.
Hey, you got to quote an anecdote from Morley Safer :) If cross-cultural marriages are a clue (I found some stats but they are in Finnish), in the last few decades Finnish men have married Russians, Estonians and Thais, and women have married Americans, Turks and Brits. The numbers of more "exotic" pairings are about equal.
fair enough. but i would be highly skeptical of any generalization from finns, who are among the freakiest people on the face of the earth!!!
I look at this situation in a good way.The parents of these children can say they they have two beautiful children with two differant skin tones.There hearts and love dont change with the color of there skin.When these beautiful angels grow they will probly have ther pro's and con's of the situation I look at it as amazing them being unique. I look foward to seeing them when they get older.God has a plan for every thing that he does and they are a work of god.The twins will learn on how they became so differant and is going to have knowledge of the situation and they are going to educate other.May God bless you and your family. Ps. Are you going to have any more children and I know it will be exciting to look forward to the arrival of your next.
You use the term "colored?" Here that's a slur and we say "people of color."
You use the term "colored?" Here that's a slur and we say "people of color."
with all do respect, you can kiss my brown ass :-)
lol, hey I purposely didn't say, "you STILL use that word?!??!" Just reminded me of a Family Guy quote actually (maybe from the episode with Chris trying to avoid his freshman hazing) when Peter(?) is about to depart for a trip to South America and Lois's dad tells him: "...and the word 'colored' still flies down there, so get your fill."
i would be highly skeptical of any generalization from finns, who are among the freakiest people on the face of the earth!!!
I know, we can only aspire to the gold standard of white people everywhere, the rural American
Windy,
IIRC you are an ethnic Finn living in Sweden.
I read a book a while back on the history of New Amsterdam (New York) and one of the interesting tidbits in it, was concerning the Swedish colony of Delaware, and that the Swedes, being surrounded by forest on all sides, decided that the ideal pioneering settlers would be Finns, particularly Forest Finns. So they brought hundreds of Forest Finns - Finns who lived by slash-and-burn agriculture - to the colony to clear the forests. These Finns traditionally lived in log cabins, and did some trapping and hunting, and for the most part the early frontier lifestyle, was based on their culture.
So when you look at rural Americans, you may be actually looking at the cultural, if not the actual descendants of Finns?!
I didn't get the impression that the mother-in-law was racist
You must be using a different definition of "racist" than I am, because that strikes me as being very racist, in the sense that it divides people up by artificial socially-derived categories based on skin colour and/or superficial appearance, and/or who their ancestors were. (Case in point: Would you call Walter Francis White a black man? Under the US Jim Crow laws, he was...)
Tan folk are way hotter. h/t: Light-skinned-ed Girl
Yep, I've heard of that theory, and as jaakkeli is wont to tell us, there are other parallels between rural America and Finland.
Interrobang:
Just dividing people up in groups is not racist, perhaps the racialism/racism distinction would be useful here. Or not.
"additionally abos of the deep desert are often blonde."
Just so you know, the phrase "abo" is one of the more offensive racial slurs in Australia...
Just so you know, the phrase "abo" is one of the more offensive racial slurs in Australia...
ah, ok. tx.
Americans are obsessed with skin color but so are the Indians and many Asian nationalities. It all comes down to white privilege, whether you are born into it (as in the US) or thrust upon a white person (as in India or Asia). Heck, if I am a white woman and get all the privilege that Indians and Asians would thrust on me, with high paying modeling contracts or role in the movies, I would not want marry an Asian or any other non-white person. I would want to marry a white person and want my daughter to marry a white person as well so that they can all enjoy the ill gotten and (wrongly thrust upon) white privilege.
"yeah. i've heard this. but there is a fair amount of social science research in the USA that women are much more racially conscious than men when it comes to hittin' it, so i'd like to see some quantitative data on these trends."
Here in the US, you are absolutely right and the white women are leaders when it comes to being obsessed with white skin color and racial features, so much so they dont have a clue about other cultures or religious differences. For instance, a white American woman in Singapore did not like the fact that her Asian Indian colleague was single and was trying to set up this Brahmin South Indian woman with a moslem Pakistani.."you all look the same" she told her, "it is not like you are dating a white or a Chinese."
could it be that the so called "white baby" is quite white just light skinned an dmay very well get darker in the future..babies do change..I am of mixed race and my mom says that I looked very ligth skinned to the point of being white and I had straight hair..but as I've grown I have gotten darker..maybe that is just what happened..and It could be that the darker baby would have adopted other phenotypic characteristics of whites as he grows because i have seen dark skinned biracial babies...