NYT: Researchers Say Intelligence and Diseases May Be Linked in Ashkenazi

[DeepModem Mom]

Researchers Say Intelligence and Diseases May Be Linked in Ashkenazic Genes
By NICHOLAS WADE
Published: June 3, 2005


A team of scientists at the University of Utah has proposed that the unusual pattern of genetic diseases seen among Jews of central or northern European origin, or Ashkenazim, is the result of natural selection for enhanced intellectual ability.

The selective force was the restriction of Ashkenazim in medieval Europe to occupations that required more than usual mental agility, the researchers say in a paper that has been accepted by the Journal of Biosocial Science, published by Cambridge University Press in England.

The hypothesis advanced by the Utah researchers has drawn a mixed reaction among scientists, some of whom dismissed it as extremely implausible, while others said they had made an interesting case, although one liable to raise many hackles.

"It would be hard to overstate how politically incorrect this paper is," said Steven Pinker, a cognitive scientist at Harvard, noting that it argues for an inherited difference in intelligence between groups. Still, he said, "it's certainly a thorough and well-argued paper, not one that can easily be dismissed outright."...


http://www.nytimes.com/2005/06/03/science/03gene.html

[bemildred]

1. There is more to this thinking business than just slapping ideas together.

Hypotheses are a dime a dozen.
Good ones are rare and precious.

This is not a good one, it is loaded with hidden and
unsupported premises about global conditions in medieval
Europe, about genetic change, about reproductive advantage.

[Gormy Cuss]

2. The second page discussion is fascinating

The Utah team's conclusions seem extraordinary to me but this is not my discipline. The brief comments by other scientists on possible alternative explanations is great as is the thumbnail sketch of the Askenazi role in Europe.

[Coastie for Truth]

3. An evolutionary Response to "Arendation" and "Discrimination"

The article goes on to say that evolution had to counter a sudden threat by favoring any mutation that protected against it, whatever the side effects. Ashkenazic diseases like Tay-Sachs, are said to be a side effect of genes that promote intelligence.

The "arendation" model was suggested by Dr. Jared Diamond of the University of California, Los Angeles, who wrote in a 1994 article, "is selection in Jews for the intelligence putatively required to survive recurrent persecution, and also to make a living by commerce, because Jews were barred from the agricultural jobs available to the non-Jewish population."

Harpending, Cochran, and Hardy have built on the "arendation" idea, arguing that for some 900 years Jews in Europe were restricted to managerial occupations, which were intellectually demanding, that those who were more successful also left more offspring, and that there was time in this period for the intelligence of the Ashkenazi population as a whole to become appreciably enhanced.

The "intelligence gene" is statistically linked to four devastating genetic diseases --- Tay-Sachs, Niemann-Pick, Gaucher, and mucolipidosis type IV -- are caused by mutations that affect the cell's management of chemicals known as sphingolipids. A second cluster of diseases affects repair of DNA.

One could argue that there is a resistance to some external disease (like cyctic fibrosis enhances resistance to plague), but Harpending's team argues that Ashkenazim and Europeans lived together in the same cities and were exposed to the same microbes. If disease were the agent of selection, the Harpending team argues, the European population would have developed a similar genetic response.

How do these disease mutations affect intelligence. In the original paper the Utah researchers cite evidence that the sphingolipid disorders promote the growth and interconnection of brain cells. Mutations in the DNA repair genes, involved in second cluster of Ashkenazic diseases, may also unleash growth of neurons.



"Arendation" was a Polish-Ukrainian economic discrimination in which Ashkenazi Jews were rent collectors and tax collectors for the landlord class. Historically, as described in the Times article, in France, most were moneylenders by A.D. 1100. Expelled from France in 1394, and from parts of Germany in the 15th century, they moved eastward and were employed by Polish rulers first as moneylenders and then as agents who paid a large tax to a noble and then tried to collect the amount, at a profit, from the peasantry ("arendation"). After 1700, the occupational restrictions on Jews were eased.

[GeorgeGist]

4. FYI-Original article can be found here:

http://harpend.dsl.xmission.com/Documents/AshkenaziIQ.jbiosocsci.pdf

[DeepModem Mom]

5. Thanks, Everybody! nt

[HereSince1628]

6. There may be an intelligence difference between groups

intelligence is considered to be at least partly heritable.

But I'll need to check the article to see if/how they demonstrate that the selective pressure for intelligence in commerce is much different from the selective pressure for intelligence in agriculture.
What must be demonstrated for fittness is that one group had more offspring than the other. I'll be looking for reference to sufficient unbiased geneological evidence to support that. Persistence of harmful alleles is only an interesting clue that something is going on.

The outcome of intelligence would seem to make possible the same fittness reward in both agricultural and commercial environments...A very clever farmer might be expected to produce more offspring that survive to parenthood than other less clever farmers for the very same reasong that a clever businessman might be expected to generate a larger number of descendants than less clever businessmen--greater access to resources.

Until I get into the report, I'll remain skeptical about the demands of commerce as an explanatory selective regime, and leave in play the possibility that this is another of the "just so" stories that Stephen Gould so much disliked.

[PATRICK]

7. Mormon sidebar

I understand why they are so oddly interested in Jewish studies and am really more interested what they make of the DNA proof that Native Americans are NOT related to a prophetically revealed Jewish migration to America(Ten Lost tribes bunkum).

They have pulled together a lot of sources that are not Mormon having to do with inheritance and closed in breeding.

I find the source(Utah) as bizarrely fascinating as the proposition.

[megatherium]

8. The University of Utah is not necessarily particularly Mormon.

It's a public university and I would expect typical faculty members are there not because they're Mormons but just because of the luck of the draw -- the academic job market tends to be national; if you get a PhD in something you pretty much expect to relocate if you want to be a professor. (Universities usually fly candidates in long-distance.)

[patcox2]

12. Do Utah residents have a somewhat opposite trend re intelligence.

perhaps a study could be performed to see if it is inherited from ancestors and is somehow related to the trait of susceptibility to fraudulent cultists who find golden books and magical spectacles in the woods. I have also read that Utah is rife with pyramid-scheme type criminal enterprises, again, the susceptibility to con artists, is it an inherited trait?

[Taverner]

20. The University of Utah is not Mormon however....

Since you asked, the Mormons do beleive Native Americans are the lost tribe of Israel.

[Chopin]

9. Supremacists everywhere rejoice !!!

[Lexingtonian]

10. very foolish stuff

The biology is not much good, for one thing. The immunological argument really looks a lot better than the selection for intelligence theory. If there were a functional pathway correlated with intelligence, there would be further mutations in genes 'upstream' and 'downstream' of this set. This collection of mutations just looks as if there were selection due to epidemics of something resembling bacterial meningitis in the population.

The historical genetics is also wrong. The time point for when these mutations were created or migrated into the Ashkenazi population is right at its 'bottleneck' point and when there was the relatively large admixture with Western Slavic, mostly Sorbian, refugees and other outcasts. (This is a good part of why Ashkenazi folks don't all look terribly Middle Eastern.) The residual population of Sorbian speakers and relatively pure descendents is too small to assess as a genetic source, unfortunately.

So the source of these disease associated mutations may be millenia of selection for them among West Slavic people, perhaps tribes long destroyed by German expansion (e.g. the Teutonic Knights), in present East Germany, Poland, and/or the center of what was known as the Jewish Pale. This part of Europe being pretty moderately cold, damp, and swampy, it was a historical hearth of infiltrant bacterial illness like tuberculosis. Why not meningitis and the like, whose bacterial agents depend on mucopolysaccharide and sphyngolipids, which really extends their animal host range.

[bloom]

17. ...

I'm not sure if I want to jump in here - this is one of those things that everyone wants to avoid - but I see a connection to the immunological aspect and Asperger's (of the Autism Spectrum Disorder).

Some people see a connection where people who gravitate to certain fields like computer programming and math can have certain personality types (not so sociable) and have certain similar (in fact heightened in some areas) intellectual abilities. And some people say some of these people have Asperger's.

Add to that - people who see a genetic component to this tendency. And also an immunological component - it has been noticed that people with Autism/Asperger's have low glutathione levels - that basically they don't excrete mercury and other substances (esp. a problem at certain times of their development pre/and/or post birth) which may be related to how they think and are subject to other related problems associated with that.


So my point is - if you took away the religious/ethnic aspect that drives people away - you could be left with something that people could consider might be something. But with the religious/ethnic aspect - it might be too hot a topic. :shrug:

[XemaSab]

11. I'm not a genetecist

so why are these diseases the result of "selection" and not "inbreeding"?

I'm also not a medieval historian, but it seems like Jewish communities would have had VERY limited mate choices for a VERY long period of time, and that could also provide an explanation for rare genetic diseases... one person gets an odd mutation and passes it down the line, and it's fine until the grandkids start marrying and having kids, and then it's a problem.

Yes? No? Why? Why Not?

[HereSince1628]

16. I don't think its the existance of the diseases but the persistence

of the genes that are linked to them that creates the speculation.

The easy and common example to explain this "heterozygote advantage" is the experience of people with sickle cell anemia in malarious areas.

Sickling cells change their cytoskeletal structure at low oxygen tension. Malarial parasites in the blood cells are damaged by this, but the sickling can also clog blood vessels...

Ignoring genes on sex chromosomes and those that aren't in the nucleus, we traditionally think of two copies of each type of human gene.

In an area with malaria a person with no genes for enhanced sickling (say 0/0)can't use enhanced sickling to fight off the disease. A person with both copies of a sickling type (+/+) has trouble with enhanced sickling causing blood cells too clog up vessels. A person with one + and one 0 type of the gene (-/0) is termed a heterozygote (for embryo with both types). In the case of sickle cell disease this heterozygote survives better(in the presence of malaria) than the homozygotes (embryos with the same types). One homozygote is more susceptible to malaria than the heterozzygote and the other homozygote is more susceptible who may die prematurely of vascular problems than the heterozygote. Hence the phrase heterozygote advantage.

Because the _combination_ is an advantage, natural selection can't work to reduce the frequency of the genes that can cause sickle cell disease when present as a homozygote combination.

So whenever a genetic disease seems persistent, biologists wonder if it might be due to some sort of historic or current heterozygote sort of advantage. The pattern of persistence of a "bad gene" _could_ be a clue to this advantage mechanism.

Advantage in genetics means it somehow aids in either or both of survival to parenthood and an average increase in the number of offspring to each individual with a specific combination of the trait compared to other individuals who don't have the trait.

MANY things other than genetics contribute to how many children human parents have. Getting geneological records to demonstrate a gene combination's fittness compared to other combinations while controlling for possible other effects that could disguise or interfere with the fittness contributed by the gene is HARD.

[XemaSab]

21. Thanks for the explanation

the part I'm still confused by is the "heterozygote advantage."

Let's use sickle cell as an example. My understanding, based on your explanation, is that either your cells sickle or they don't, and they wouldn't in someone with one but not two copies of the gene (a heterozygote). Therefore, no advantage would be conferred, but fitness as measured by offspring that survive to reproduce would be decreased if your mate also was a carrier. Am I wrong about this?

If it was a trait that wasn't either/or, like skin color (I know there's many genes that control skin color, but it's an example), then a partial advantage could be conferred for a heterozygote, say, Vitamin D synthesis vs. skin cancer protection.

At any rate, until the advent of modern genetics, most carriers did not know they were carriers, so it's not like people intentionally passed on these genes. The question is how they bacame so concentrated.

[HereSince1628]

23. it's sort of a goldilocks principle

O for both copies = a no genes homozygote (0/0)who has no enhanced sickling & no protection

- for both copies = a 2 sickling gene homozygote and very enhanced sickling which leads to sickle cell disease

one + and one - = the heterozygote, which is "just right" and the individuals like this have sickling enhanced enough to help protect from malaria, but not enough enhancement to cause sickling disease.

You're right that sometimes gene expression is either on or off. In simple dominant-recessive type traits gene expression is all or nothing. Gene expression isn't always all or nothing, sometimes its in between what is called incomplete dominance.

There isn't room here to get much deeper into it. Basic genetics is an entire unit in a biology class but I expect their are websites that explain things like heterozygote advantage as well as incomplete dominance better than I can.

[XemaSab]

24. I've taken basic biology

But the question of how much real selection is occurring in "modern" times seems to open some large cans of worms.

For example, there's a correlation worldwide between women's education levels and total fertility, where more highly educated women have fewer children, which from a Darwinian standpoint seems to make education maladaptive. Stating that smart Jews left more offspring seems to open a similar can of worms. I've known a lot of smart kids of all races and ethnicities, and I'd guess it has more to do with parents pushing their kids to study hard than any innate gift at, say, math.

[jwcomer]

25. I can't speak directly for the researchers

However, I suspect that they would concur that in the modern era education is not increasing progeny. However, the study is not dealing with the modern era. It is dealing with Dark Ages Europe, where having more money did in fact lead to more adult children. There was no social safety net for the poor and there was no Green Revolution providing ample produce for comparably small amounts of cropland. Life for the poor in the Dark Ages was cold, brutal and short. The authors make the case that it would have been particularly brutal for poor jews lacking the right to do farm work. The thesis is pretty compelling; by which I mean, plausible. Whether it is true is going to be hard to determine. And the PC crowd is likely going to have a conniption over this one. Not being Jewish, I don't feel a have any strong bias on the issue. It seems a reasonable argument. But the greater implications a.la. the Bell Curve are very uncomfortable.

[NorthernSpy]

13. this leaves a bad taste...

:think:

It's worth remembering that the Nazis never accused Jews of being stupid. They did, however, accuse Jews of being "underhanded", "conniving", and "predatory". Furthermore, they claimed that these alleged traits of mind were bred in the bone -- and therefore unchangeable. This claim of inherited character was pressed into service as a rationale for genocide.

This 'genetically-based intellectual superiority' stuff is poison candy. Swallow it, and pretty soon we'll see that intellect is not the only mental characteristic that will be claimed as ethnically based.

People who make claims like these usually have an axe to grind. I think that the last century showed that some axes need to stay unground.

[hector459]

14. You beat me to it. Precisely what I was going to suggest.

Thanks.

[cestpaspossible]

15. 'the genetic issue of natural selection versus founder effects'

I don't really understand 'founder effects' based on this NYTimes article... can someone help me out?

[Igel]

18. If you have a population with a low frequency of a gene or

trait.

Founders are usually a small group from a large population. The smaller the sample, even if random, the greater the odds it won't be representative.

(This is ignoring the possible non-randomness of the sample, but there's usually no reason to think the trait under discussion bears upon how the sample's selected, or self-selected.)

[Lisa]

26. example of founder effect -- coat color in black bears

On a couple of West Coast islands, there are significant populations of white "black bears" -- the Kermode or spirit bear. The genes causing this are found in other black bear populations, but are far more common on these islands (something like 10% of the bears there).

Some people have suggested natural selection is playing a role, but there doesn't seem to be any significant survival difference between the white and normal-colored bears. And if the mutation was advantageous during the Ice Age, it still doesn't explain why other areas in North America which were also glaciated (and have far more snow cover than the West Coast today) don't also have spirit bears.

Another example -- grey squirrels in Eastern North America. There are black ones and grey ones, but in some cities where they've been introduced, you only see one color. It's been suggested that this is due to natural selection (climate or predation), but the pressures don't seem to be that different from the rest of the continent. Given that the starting populations were very small (only a dozen or so), it's more likely that the sampling itself is more important. (If there weren't any black squirrels in the group selected for release, that would affect the composition from the start.)

Rather than environmental determinism, stochastic (chance) factors like the founder effect may be playing a role. As igil pointed out, if you have a small population (and breeding is restricted to those individuals), the genes carried by one individual can have a major impact on that population -- if they are rare genes, they may end up being more widespread than in the general population. Because of inbreeding, mutations which are only mildly advantageous (or which might even be somewhat inconvenient) will spread. Examples of the latter have been seen in human populations of isolated islands: a gene believed to make people susceptible to asthma, on Tristan de Cunha; and the hereditary disease achromatopia (a form of color blindness) on Pingulap.


Another stochastic factor that enters into things if the population is isolated for a long time is "genetic drift". You only pass on some of your genes to your offspring. Over generations, some genes might simply not make it, while others may come to dominate. A non-genetic example of this -- the ex-Bounty sailors who settled on Pitcairn Island. Some of the families who live there today still have Fletcher Christian's surname. But other surnames have gone extinct -- not all the sailors had male offspring who carried on their names, to the present day. (Actually it IS kind of biological, since their Y-chromosomes wouldn't have been passed on either.)

[Igel]

19. This is, again, the kind of research that can be neutral, can

be bad, or can be good.

It'll probably make no headway because politics will get involved, even if the politicians are hands-off.

Science and pseudo-science can be used for bad. It's always been so, whether we're talking fissionable materials and GPS, or fire and obsidian.

[Maple]

22. Here's a thought

which will probably get me into trouble...but I put it out here anyway for consideration and comment.

Jews have always been considered to be intelligent. Even their worst enemies never thought of them as stupid.

Jews pushed their brightest boys into being rabbis...a job that required memory, intelligence and wisdom...and married them to their brightest girls. They had children.

Catholics on the other hand made their brightest boys into priests, and their girls into nuns. No marriage. No children.

Has it made any measurable difference today?