Genes and Culture: Ear Rice, Light Sweat, Red Faces, Drinking Places

There’s a few neat fact most people seem not to know, regarding genetic differentiations between East Asians and everyone else, and it they’re neat enough to post the going theories about…

One particular trait that came into the news a few years ago (2006) is related to sweat and ear wax. (That there was the layperson’s link, but if you want the hard science and have access to Nature, look here.) Which one’s grosser? Ear wax? Okay. Well, there are two kinds of ear wax in humans: brown, wet, waxy stuff, and yellowish-white, drier, flaky stuff. If you’re a Northeast East Asian, or of Native American ancestry, chances are that your ear wax is the latter type. (Though bear in mind, this is for pre-Contact gene pools; if your great-great-grandparent was one quarter Cree, I have no clue what type your ear wax will be.) If you’re from an African or European gene pool, chances are your ear wax is the former type, darker and wetter. Central Asia is mostly a mix, and Southeast Asia is something of a mix too.

Why the adaptation? It seems not because of earwax itself, but rather because the gene that causes the wax to be drier and flakier also seems to control perspiration — people with the drier earwax sweat less. Which one can imagine would be handy in certain conditions. (The researchers who reported it theorized cold weather, given other adaptations like East Asian nostril size.)

So, yes, there’s a genetic link between why, in Korean, ear wax is called 귀밥 (gui-bap, ie. “ear rice” — because it comes out pale and flakey and dry) and why it used to be so darned hard to find deodorant in stores.

(If I could “buy” this adaptation, I suspect I would. The humidity these days drives me nuts, making me sweat much more than I’d like!)

Another trait that came up in a recent discussion about drug control on a mailing list I’m on, about drug controls, drinking cultures, and the Prohibition. I made an example of drinking culture in Korea, and discussed how he main drinking style here is drinking to get drunk, even though a number of people here seem also to have trouble breaking down alcohol; I also discussed what I’ve noticed about how people react socially to the effects of that condition.

(Men I’ve met affected with this condition usually sort of grin and bear it, but women especially are very self-conscious of it. I’ve heard a lot of women say they feel that they look stupid, foolish, or dumb when their face reddens from drink. I haven’t heard nearly as many men say this. The men seem less embarrassed than the women, in my experience, but that’s limited experience, remember, and even the guys seem somewhar embarrassed by it.)

The condition, in any case, apparently is called in technical terms “acetaldehyde dehydrogenase deficiency,” but don’t let that scare you. The way regular people talk about it is, “Ah, yeah, some Asian people don’t produce a lot of that enzyme that breaks down alcohol so they get red-faced and sick when they drink!” This is known colloquially by a multitude of names in English: Asian Flush, Asian Glow, Asian Red, and so on.

The question, of course, is why some people (people bandy around numbers like 40% or 50% of East Asians) would come to have that condition. And the answer suggested in an article titled ” Why can’t Chinese Han drink alcohol? Hepatitis B virus infection and the evolution of acetaldehyde dehydrogenase deficiency” is interesting. Basically, the idea is that the populations in which this mutation are common all live in places where Hepatitis B is also endemic. Hepatitis B and heavy alcohol consumption kill your liver way faster than Hepatitis B alone, or heavy drinking alone. If you aren’t able to drink heavily — because you have this mutation — then you’re unlikely to die from heavy drinking — but you’re also unlikely to accelerate your own death by unknowingly combining hepatitis B and heavy drinking. So people with this mutation would have tend to be better at surviving a (common in these areas) infection of hepatitis B, possibly to the degree that it would be selected for.

So one reason some of your (probably Asian) friends turn red in the face when they drink and can’t drink much is because this was an evolutionary advantage to their ancestors, thanks to the prevalence of hepatitis B where their ancestors lived at some point… or so the theory goes. Well, that or maybe the alcoholics all died faster, and that would be why the rate of alcoholism is lower in places where this is common — 10-20% lower, according to this article.

Which may not be much consolation, but the neatness of knowing has got to be worth something… it might at least save some people from wasting money on this sort of thing. While a drug simulating this condition seems to have been developed for the treatment of alcoholism, there doesn’t seem to be a “cure” for the “Asian Glow” beyond, maybe, dosing with antacids or fructose/glucose — and even those, according to doctors quoted in the article linked in the paragraph above, might only facilitate such individuals to drink more only to bring on all kids of awful cancers or liver conditions, to which they’re more susceptible to begin with, or an early death from alcohol poisoning.

What seems curious, though, is how alcohol would be such a big part of social life in Korea despite all of this. According to Dong-Kwon Lim, a folklorist, drinking has always been a distinctly important part of Korean social life — one that differentiated it from China’s or Japan’s. Indeed, Lim claims that “inns” were considered, by Koreans, “drinking places” (as opposed to “eating places” in China and “sleeping places” in Japan — I have no idea what the older terms are, though, since he doesn’t give them). As he writes in In Search of Korean Folklore:

In the Korea of the past, a person was often called heroic or manly if he could drink well, while those who could not were considered unmanly. So a man was judged by how much he could drink and the size of a drinking party was also used as a barometer when people evaluated a family’s generosity. The party could not be judged a success if all of the participants returned home without some incident. Id some of the guests happened to fall down into a ditch, the family was said to have thrown a good party. While this may be unimaginable in other countries, Koreans had their own standard of evaluation using alcohol as a criterion.

I’m not so sure that these standards are unthinkable in other countries, of course — especially not historically speaking. I would wager that some Northern European societies — why am I thinking of cartoonlike Vikings like those featured in How To Train Your Dragon? — had similar standards, and that indeed even today, if you but visit a fraternity house at any American university (or a “student ghetto” like McGill Ghetto in Montreal, or wherever one can find a large concentration of students in Britain), I’d wager the same essential criterion exists… though absent, of course, as high a concentration of the Asian Flush.

And that’s what is particularly intriguing to me: why would a drinking culture of that kind develop in a place where so many people just cannot drink? Quite curious.

6 thoughts on “Genes and Culture: Ear Rice, Light Sweat, Red Faces, Drinking Places

  1. The usual explanation for why people (or animals) engage in seemingly self-destructive behavior is “signalling” and “screening.” (Economists first came up with the idea – evolutionary biologists later co-opted it). When you (usually male) engage in a dangerous or wasteful behavior (classic biological example is tails of peacocks; the classic economics example is a Ph.D in philosophy), the reason is to show (“signal”) the female (or your employer) that you are just so good that you can overcome the hardship of a long useless tail, or an education which is difficult but practically useless. It signals your innate talent, and the female (or your would-be boss) uses it to “screen” how acceptable you are.

    So if you can handle being drunk, you are more capable than those who cannot. The popular anecdotal evidence (e.g. drunken one night stands) seems to suggest that the strategy is successful.

  2. Junsok,

    Yeah, I ran across that idea in a book by Jared Diamond, The Third Chimpanzee. He uses, I think, the example of some American civilization (Mayans, maybe? or Aztecs? I can’t remember) who did enemas with various intoxicants… which cuts out the middle-man filtration of the liver and puts the crazy stuff right into the bloodstream. Which is an even bigger risk, really.

    Of course, the question is, what are you signalling the ability to handle when you’re drunk?

    Which makes me think going to karaoke is the wrong move after getting hammered — what one should do is have everyone write up reports or try produce advertising pitches for and see who gets the best results.

    Then again, that’s the point of view of someone who thinks office work is about the productivity, not about the social stuff. If you’re more interested in social interaction and handling of that, then I suppose getting drunk and “hanging out” in a social group — one where abandon is indeed encouraged, like singing songs and dancing and so on — is exactly what you want to do to see how will manage to hold the lines and etiquettes straight in their heads even when hammered.


    But then, if that explains it… is Lim exaggerating how unique it is to Korea, or if not, why didn’t a similar signal/screen pattern develop in Han Chinese popuations with the same genetic tendency for acetaldehyde dehydrogenase deficiency?


    And, gah, what the hell happened to my formatting? I’ll have to try fix that. Grrr.

    Fixed. No idea why div tags appeared out of nowhere. Annoying.

  3. This is a cool article. However, I’m not sure that everyone whose face turns red and can’t hold booze has a gene to determine that.

    I immediately thought that I have this same condition.

    Then I googled “Jews” and “alcohol intolerance” and voila, I got a bunch of hits on sites and articles which claim that Jews have the same genetic intolerance that Asians do.

    It reminds me of all the (recent) newspaper articles about Jewish DNA. Who the hell cares if the Jews are really descended from the same ancestor or if some are Khazarian descendants and not from the fertile crescent after all?

    BIOSOCIALITY. Rabinow argues that new social groups are forming on the basis of perceived biological similarities. And old social groups are searching long and hard for biological bases to justify their past and future existence as a group.

    I would go so far as to argue that “East Asian” is a socially constructed group, not a biologically objective population unit.

    Similarly, “Jewish.” Or for that matter, “Easterner,” and “Westerner.”

  4. Bradley,

    Aw, I would have thought this would be the perfect place to make the “Jew’s Ear Juice” connection (re: your other comment today) but I’ll just ask… d’ya have the flakey or the wet ear wax?

    I’d have expected Jewish DNA to have been more diverse — from more intermarriage across gene pools — as a result of history and the whole diasporic thing.

    I’m of two minds regarding the argument that “East Asian” or “Northeast Asian” is a socially constructed category. I mean, the name itself contains a geographic reference, and geography, at least for certain groups, has until pretty recently been — when you look at the coarse granulation of statistics — a pretty powerful isolator on gene pools. Yes, some Arabs and Mongols and Indians married with Koreans back in the old days and had kids. But most Northeast Asians probably had kids with other Northeast Asians, which is why, diversity included, there are overall some pretty general ranges of traits we can find statistical occurrences for, and others we can’t. (How many Koreans born to ethnically Korean parents have blue eyes and blond hair? How many have the kinky hair of an African? The skin color of a South Indian? Probably a very few… I know one Korean guy with naturally curly hair. But most aren’t. Brown hair, we see. Blond, or red? Not so much.)

    I’d argue there are “ethnicities” which end up being social constructions, especially for groups that have either been dispersed or have long had offspring (even if not intermarried — like whites and blacks during the days of slavery), or otherwise have mixed together (the Metis in Canada being one example of a more common intermixing of Native Americans with others over the last few hundred years).

    I don’t know to what degree we can really say the same of the constructedness of Korean ethnicity (as opposed to national identity, which is completely constructed of course, everywhere). Surely we can, but I don’t know how much, or whether it’s statistically relevant.

    I mean, I have a friend who’s Han Chinese, and told me that she had some condition — I think it was that her ribs cracked when she coughed too hard — that according to her doctor was much more common among certain ethnicities, including Han Chinese. She said the doctor said those kinds of details are often useful, diagnostically, but that it’s harder when a patient is of mixed race to put such information to practical use.

    So I’d argue that a totalizing idea of any “race” is scientifically useless, but as far as doing the numbers game, “race” as the phenotypical expression of ancestry in a particular gene pool might or might not be of use for an individual. (Though it will likely become less useful as globalization and mixing increase, so yay for personalized genetic profiling, I guess? Er, maybe…)

  5. FYI Gord, I have one of the juiciest ears of any Jew. Prolific emissions of gooey…ugh. My kids have inherited this trait from me, so our Korean babysitters freak out when they see it. They think it is a sign of an ear infection, when in fact, my kids are just little Koreans with Jew’s ear juice oozing out.

    As for the genetics…yes, Jews are a mixed bunch but the researchers are fixating on alleles specific to the Y-chromosome which are supposedly indicative of descent from the Cohen (priestly) caste. A patrilineal inheritance irrespective of mixing with non-Jewish mothers.

    That’s fine for Jewish patriarchal ideology.. except that there is a Bantu-speaking tribe in southern Africa which has the same gene. They also have an oral history of migration from Israel to Africa. Some people are scratching their heads over this while others say it just confirms the tribe’s oral history of origin in Israel.

    So one way of sorting out cases of racial mixing is to focus on either mitochondrial DNA or else on Y-chromosome alleles. Otherwise, as you said, personal genetic profiling may be best…

    Genetic studies show that Japanese have diverse ancestry, including some DNA traced to australoid populations similar to the Philippinos. Does that mean they are not really “Northeast Asians” or they are less “pure” than Koreans?

    Furthermore, even if the Koreans married only other people on the peninsula, there were many non-interbreeding groups that would have fostered genetic variations due to simple genetic drift. For example, aristocratic versus commoner classes.

    These genetic variations are often not expressed as the visible phenotypes that we are culturally trained to notice. Such as the kinky hair or eye or skin color that you mentioned. In fact, the vast majority of human genotypes are expressed only at the enzymatic or molecular level, not at the visible level. Hence, Koreans may have absorbed DNA from many non-peninsular sources or else may have generated their own extensive mutations, without actually displaying color differences such as blonde hair or textural differences such as curly hair.

    BTW, I gave a lecture last semester on a chapter in Diamond’s “The Third Chimpanzee” and I was disappointed that the material flew so far over the heads of the students. Do you think it is a difficult book for students? I thought it should be just fine…

  6. Bradley,

    About your particular ear juice: TMI, pal. Really. But it’s funny the nannies freak out about it.

    As for the genetics of the Jewish race, wit’s interesting that it’s in part patrilineal Y-chromosone alleles… since orthodox Judaism depends on tracing matriarchal lineage, right? (Or am I remembering something wrong?)

    The Bantu group — yeah, doesn’t surprise me at all. History seems to have been such a weird place, compared to how we imagine it. Though, really, that’s the failure of our imaginations, is all.

    Mitochondrial DNA… have you read that story, “Mitochondrial Eve” by Greg Egan? It’s available on Fictionwise for a little over a buck, and worth every penny.

    (I’d loan you the book if I had it, but I’m pretty sure it’s in a box in Canada.)

    Genetic studies show that Japanese have diverse ancestry, including some DNA traced to australoid populations similar to the Philippinos. Does that mean they are not really “Northeast Asians” or they are less “pure” than Koreans?

    Well, since I’m starting out with the assumption that no group is “pure,” purity doesn’t really come into it. What does is the degree of mixing. I don’t know whether it would make sense to classify Japanese as a different group from other Northeast Asian groups. I would suspect that whoever was on the Japanese islands before their more recent invasion from the Asian mainland (like the Ainu) probably was also respresented on the mainland, earlier. And since Japan stretches pretty far south and North, that’s a lot of room for different groups to settle on different islands.

    A few Koreans have told me that modern Koreans are actually two different groups: the indigenous people of the peninsula at the time when the folks who migrated out here from Lake Baikal arrived. Who knows how much truth there is to that, but… the point is, anyway, that even with the inevitable diversity, there are major tendencies that form in each semi-isolated gene pool. You’re right that I exaggerated the phenotypical significance, of course… but I think that there are cultures or groups where this is more of an issue, and others where it is less of one. I would wager that gene pool stability has remained greater within certain groups of people than others.

    As a side note: I often notice Koreans who have traits I’d classify as non-Korean, like a particularly Middle-Eastern-looking facial structure… the kind of face that makes you think, “This person must be descended from some Arab trader who married in here long ago.” Could be wrong, of course… it could be the luck of the genetic draw, but sometimes it’s hard to not imagine. It fits with your point about being culturally trained to notice (or not notice) certain phenotypical markers… though, who knows, in a society where there’s actually a word for “uneven buttcheeks” probably that “foreign nose” does get noticed.

    I do remember being quite stunned at the range of skin colors that are common in Korea — from very pale to very, very dark, really. Some of that’s socially constructed too — people who wear sun cream all the time, day in and day out, versus people who don’t — but some people I’ve known wore suncream but just were naturally darker.

    As for particular cultural structures, I’m not sure they’re stable enough long-term to manifest in anything like genetic differentiation between social classes. I have wondered about whether there would be any genetic marker for people from an historical slave class, versus the free classes. I’d imagine the first slaves in Korea were held as prisoners of inter-kingdom warfare, and slavery was hereditary. But I’m not sure looking would reveal anything noticeable — as I say, I doubt even the long-term system of slavery was stable long enough to show differentiation. I’d be curious to hear what different Korean geneticists — across a range of political dispositions, especially — would have to say about that.

    And as for Diamond’s “The Third Chimpanzee” … I have no idea, since I don’t know the level of your students. Which chapter was it? You know, the book is available in Korean translation, right? When I ask students to read particularly challenging content for class, I tend to try choose something available in Korean translation, and then make it short enough they can read the Korean, and then look over the English afterwards so they know the English-language terminology. Seems to work, at least with those who are motivated enough to follow through. (For those who aren’t motivated, nothing works, so hey!)

    The comments I’ve heard from SF-fan friends suggest that science in itself seems to intimidate a lot of people here, since science education apparently isn’t the sort that fosters a real interest in science. (Which is one reason they say it’s hard for SF to become popular here.)

    I recently surveyed a few classes about whether v=t*9.8m/s2 — you know, high school physics, the basic point that air resistance ignored, it doesn’t matter whether stuff is heavy or light, it accelerates towards the surface of the Earth at the same rate. I asked without bringing up the formula at all, just in simple terms — “If I drop this pencil case and this pen at the same time, in what order will they land on the desk?”

    In one class, about a third of the students got it right, half didn’t know, and the remainder said it depended on the mass of the object. In the other class, a writing course, I was stunned to find that nobody knew the answer, not even the several science majors.

    I discovered this by accident, by the way: I was hoping this would be a good example for the science major whose work we were critiquing, in terms of considering one’s audience. I started out with, “Imagine someone asks you why the sky is blue. Okay, in scientific terms: why is the sky blue? Explain.” She shrugged and said, “I dunno,” so I invited anyone to explain. They couldn’t explain in scientific or in layperson’s terms. Then I asked about gravity, and also about why the Earth has four seasons. Now, sad as it is, I am not surprised when humanities people can’t explain those things, but science majors? It was pretty depressing, since I knew this stuff back in middle school. (Well, except maybe the four seasons thing… I was taught it in elementary school, but not clearly. I think I learned it better in high school.)

    Well, but maybe all the science-minded kids are down in Pohang? Hmm.

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