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Medical Forum / General / General / July 2005

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RACE

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outrider - 18 Jun 2005 18:02 GMT
The new science of race

By CAROLYN ABRAHAM

Saturday, June 18, 2005 Updated at 2:28 AM EDT

>From Saturday's Globe and Mail

Henry Harpending is about to titillate the world's conspiracy theorists
with one of the most politically incorrect academic papers of the new
millennium.

Why, he and his colleagues at the University of Utah asked, have Jews
of European descent won 27 per cent of the Nobel Prizes given to
Americans in the past century, while making up only 3 per cent of the
population? Why do they produce more than half the world's chess
champions? And why do they have an average IQ higher than any other
ethnic group for which there's reliable data, and nearly six times as
many people scoring above 140 compared with Europeans?

Prof. Harpending suggests that the reason is in their bloodline -
it's genetic.

The 61-year-old anthropologist's explanation is not easily dismissed,
but it crosses into the territory scientists fear most.

His group's theory is that during 1,000 years of persecution, social
isolation and employment restrictions in Europe that kept Ashkenazi
Jews from farming, they were forced into (then disreputable) jobs such
as trade and finance, which demanded mental agility. Success in these
fields could lead to food, shelter and family. Under such pressures,
the paper suggests, genetic traits related to intelligence became more
prevalent among central and northern European Jews.

Two U.S. journals refused the paper, an unusual experience for this
widely published scholar. "We finally had to send the paper to
England, where they're not so obsessed with political correctness,"
Prof. Harpending said.

The danger of bolstering bigots is what has scientists so nervous. If a
complex trait such as intelligence can be inherited, for instance, and
you say one ethnic or racial group tends to have more of it than
others, does it follow that another group has less?

Ever since the eugenics movement a century ago, which led to forced
sterilizations in Canada and the United States to improve the racial
stock of the human species, and then the horrors of Nazi Germany, such
questions have been taboo.

University of Western Ontario psychologist J. Philippe Rushton was
internationally condemned 15 years ago for claiming to discover
differences in brain size, intelligence, sexual habits and personality
between whites, blacks and "Orientals."

Yet the role of race in genetics is a subject scientists now believe
they can't ignore. The future of medicine may depend on it.

In fact, a massive international effort, which includes many Canadian
researchers, has been quietly under way for nearly four years to
catalogue and compare the genetics of people with African, Asian and
European ancestry.

It is called the Haplotype Project. You may not have heard a word about
it before now. But by the end of this year, society may have to start
facing its implications.

It was not supposed to be this way.

When the Human Genome Project was completed in 2000, its most touted
result was that it showed no genetic basis for race. In fact, some
scientists went so far as to dub race a "biological fiction."

The project was a 13-year international drive to map all of the three
billion chemical bits, or nucleotides, that make up human DNA.
Particular nucleotide sequences (represented by the letters A, C, G and
T) combine to form the estimated 25,000 genes whose proteins help to
produce human traits, from the way your heart beats to the wave in your
hair.

The map indicated that humans as a species are 99.9 per cent
genetically identical - that, in fact, there are greater differences
between two frogs in a pond than between any two people who find
themselves waiting for a bus.

A teeny 0.1 per cent, a mere genetic sliver, helps to account for all
the profound diversity within the human race, with its freckles,
dimples, afros and crimson tresses, its shy and bombastic types, its
Donald Trumps and Dalai Lamas, Madonnas and Mr. Dressups, Bill Gates,
Billie Holidays, George W. Bushes and Osama bin Ladens.

It was a message of harmony: Hardly a hair of code separates us.

But five years later, one of scientists' main preoccupations has become
to chart the genetic variations between and within racial groups - to
parse that 0.1 per cent. These differences arise through mutations,
which all begin as one-time flukes, but become more prevalent in a
particular place if they offer a survival advantage, carriers have more
children or they result in a trait a society finds desirable.

Now, teams are panning for gene types to help explain why West Africa
produces the fastest runners in the world. A University of Toronto
researcher is hunting the gene types that account for skin colours.

A Pennsylvania State University scientist is teasing out the biology
behind other variable physical traits, such as height or hair texture.

More crucially, it has become obvious that the 0.1 per cent may add up
to the difference between sickness and health.

In Canada, researchers from McMaster and McGill Universities are
breaking down heart disease by nationality to understand the interplay
of genes and environment. The answers may explain why South Asians
suffer high rates of high blood pressure, why heart attacks hit Middle
Eastern men 10 years earlier than Europeans, or why the Chinese seem to
boast the trimmest waistlines in the world.

The genes discussed in Dr. Harpending's team's paper, meanwhile, are
known to be the ones that account for the high Ashkenazi rates of
breast cancer, the neurological disorder Tay-Sachs and other
conditions. The mystery is why these traits have persisted at high
rates over generations. The Utah group's conclusion (to be published in
the Cambridge University Press Journal of Biosocial Science) is that
the diseases are a tragic side effect of genes selected for their role
in boosting brain function.

Given the explosion of research in race and genetics, Francis Collins,
a former leader of the Human Genome Project, had to admit in the
journal Nature Genetics last fall that "well-intentioned
statements" about the biological insignificance of race may have left
the wrong impression: "It is not strictly true that race or ethnicity
has no biological connection. It must be emphasized, however, that the
connection is generally quite blurry."

Alan Bernstein had warned him. In the fall of 2000, the president of
the Canadian Institutes of Health Research heard Dr. Collins speak at
Harvard about there being no significant differences between races.
"That's going to come back at you," he said.

According to Dr. Bernstein, 0.1 per cent is actually far from an
insignificant difference in the genome's chemical sequence. In fact, he
said, the genetic distance between humans and gorillas is not much
greater. "It's silly to try and be politically correct about it."
What matters, Dr. Bernstein said, is to treat it scientifically.

The most organized effort to do that to date is the International
Haplotype Project. Scientists in Canada, the United States, Britain,
China, Japan and Nigeria are spending $185-million to chart the genomes
of people from Tokyo, residents of Beijing, the Yoruba in Nigeria and
Americans of Western and Northern European descent - 270 people in
all.

Using these maps to find genetic differences between ethnic groups
could lay the groundwork for new treatments and cures. It might help
predict a person's response to a given drug, and allow for tailor-made
medications with fewer side effects. It could bring the medical
advances genetics has long promised.

On the other hand, the knowledge may raise more questions about the
meaning of racial differences than anyone cares to answer.

The Quebec Genome Innovation Centre at McGill University is a cold,
sleek structure that screams clinical precision, with its glass walls,
concrete columns and lateral steel beams. The equipment inside is as
expensive as the $30-million, 50,000-square-foot building that houses
it.

Its three floors of labs and DNA sequencing technology crunch genetic
data at a rate no one even imagined five years ago. In 2001, it took a
year to run 50,000 genetic tests. Today, said the centre's director,
Tom Hudson, they can shoot out the results of 20 million tests in a
week.

This speed comes courtesy of such mind-boggling gadgets as the array
centrix, a small board of 96 fibre-optic spikes, the tips of which can
be coated in DNA and 1,500 genetic tests run on each tip - at the
same time.

"From one drop of blood, you can do hundreds of thousands of
tests," Dr. Hudson enthused.

>From one drop of blood you also can discern the ethnic background of
the person being tested with fairly good certainty.

So it is here, where technology has shrunk costs to just pennies per
test, that major sections of the Haplotype Project's "HapMap" are
being generated.

The project was born in the summer before Sept. 11, 2001. At first, it
seemed destined for obscurity. Scientists at the University of Toronto,
McGill and the Massachusetts Institute of Technology had been hunting
gene mutations that increased the risk of Crohn's disease in 200
Toronto-area families of mostly European heritage - British, Polish,
French and Greek.

In the process, they stumbled on a remarkable discovery. The genome's
three billion chemical letters appear to be arranged in blocks - like
paragraphs in a text. Some are longer, some shorter, but all have
fairly clear beginnings and ends.

The pattern seemed to make sense. In the genetic mix and mingle of
conception, the mother's and father's DNA are passed down to the next
generation in these kinds of heritable chunks. Researchers estimate
there are 100,000 such blocks in each person's genome.

What's more, gene mutations within those blocks seem to fall in the
same places, even in different families. It's like a library in which
every book contains a typo in the first paragraph on the second page,
or the fourth paragraph on every fifth page. The misprints might be
different, Dr. Hudson explained, but they occur in the same locations.
For finding genetic mutations, the pattern seemed as good as an index:
Instead of scanning the whole book, you could flip straight to page 2
or page 5.

The discovery seemed to cry out for a new map of the human genome, one
that would show the haplotype blocks and highlight each paragraph in
the book of life.

"Everyone knew this was important," Dr. Hudson said. "But there
was no big press release." Coming out a month after Sept. 11, the
discovery of haplotype blocks attracted little initial attention. But
for scientists it couldn't have come at a better time.

Traditional methods to find mutated genes in family studies and remote
populations had hit a wall. Yes, they could find the lone mutation that
led to a rare disorder such as Huntington's disease or cystic fibrosis.
But trying to find the dozens of mutations that increase the risk of
common diseases like cancers or asthma would simply require too many
patients and too much data crunching.

With a haplotype map, they would be able to search the genomes of huge
numbers of people with a particular disease, in search of a common typo
in a particular paragraph.

First, however, the HapMap researchers had to find out if their theory
would apply to the genomes of people around the world. The maps
provided by the Human Genome Project would offer little help, because
they had been rough compilations based on various people, with little
regard for ethnic background.

The next question was, whose genomes should they use?

When HapMap scientists met in Washington in 2002 to discuss the issue,
Dr. Hudson - a 44-year-old, buttoned-down geneticist much more
comfortable with technical issues than social ones - was taken aback
at the incendiary debate that broke out. It was the kind of battle that
seems bound to become more frequent as scientists continue to explore
this sensitive area.

"As Canadians, we are not used to the high emotions around race, as
they are in the U.S.," he said. In that two-day meeting and others to
come, African-American community leaders, ethicists and philosophers
unleashed their fears and frustrations.

"There were two points of view," Dr. Hudson recalled. "One of
them is, 'You're only going to be studying Caucasian chromosomes,
clearly, because you only want to find tests for North Americans and
U.S. people with money.' "

But if Africans and other populations were included in the map, there
was serious concern that any differences found in their genomes might
leave them open to another tier of discrimination, perhaps from
health-insurance companies.

In the United States, where the mortality rates for a range of diseases
are higher among blacks than whites, such disputes are common. For
example, scientists and sociologists continue to argue over whether
African Americans' high rates of hypertension are due to genes or to
environment.

One contentious theory suggests African Americans descend from those
slaves who were able to survive the dry and hungry trip from Africa
thanks to a genetic quirk that enabled them to retain moisture and salt
- which also can contribute to high blood pressure.

But others say it is due to diet and stress. As New York University
sociologist Troy Duster told The New York Times last fall, "If you
follow me around Nordstrom's and put me in jail at nine times the rate
of whites and refuse to give me a bank loan, I might get
hypertensive."

In the end, the HapMap team decided to include African chromosomes,
along with those from Japan, China and the United States. It was a
diverse enough sampling to tell them if the haplotype theory would hold
up, but selective enough for their limited budget.

At the same time, ethicists joined the project to ensure that all DNA
donors would be aware of the risks of participating - namely, that
any dramatic genetic differences the project discovered could end up
stigmatizing their communities.

"Certainly," Dr. Hudson said, "there's enough examples already of
racism in the world - before genetics, during genetics and after
genetics - that there's no doubt someone would try to use the
information for genetic discrimination."

Despite the long and ugly social history of race, there is no clear-cut
definition for the term. Is a person's race defined by skin colour,
that most visible of markers? By language, country of birth, the food
they eat or the religion they practice? Not even scientists can agree.

"If you have a [genetic] sample from Nigeria, can you really say that
it represents Africans? Is that the same as African Americans? [In some
studies], Jews are white, sometimes they're not. Sometimes they're
compared to Caucasians," said Celeste Condit, a professor of speech
communication at the University of Georgia who specializes in
biomedical issues.

"The scientists have been irresponsible for not developing a language
for this," Prof. Condit said. "Usually scientists are very careful
in developing their technical vocabulary. But it's hard to describe the
geographic dispersion of people properly - and they have these easy
[racial] terms in their heads."

Of course, geneticists already know that since people have ancestors
from all over the world, no one fits neatly into any one racial box. We
are all of us mixed, even if our complexions suggest otherwise. There
also can be greater genetic differences within racial groups than
between them.

But since no one now has the resources to uncover the secrets in every
patient's DNA, both science and medicine are using "race" as an
easy, if dangerous, shortcut.

"Until we can scan the genome of every individual," said Tim
Caulfield, director of the Health Law Institute at the University of
Alberta, "race has become this rough proxy."

Yet HapMap researchers are indeed finding that the genetic lines
between their groups are terribly blurry. In fact, the block structures
are similar in all of them.

"Humans as a species are just so young there hasn't been enough time
for the genome to alter that dramatically," Dr. Hudson said. (Frogs,
on the other hand, have a few more millennia behind them than people.)

As expected, they are finding the most variations in the DNA of donors
from Africa, where modern humans are believed to have arisen 150,000
years ago. It is thought that the rest of the planet's populations are
all descendents of a small group who only wandered out of Africa
roughly 60,000 years ago, so there has been less time for those genes
to mutate in the rest of the world.

What they do know, Dr. Hudson stressed, is that the mutations they are
cataloguing - the 10 million or so most common ones - appear to
exist in all populations. Just not at the same frequencies.

"Almost all the differences you see in people in North America are
differences you see in Africa, are differences you see in Asia," he
said. "It's very rare to have something you only see in [one
place]." And when you do, he said, it's uncommon even in that
population.

One stunning example is a gene variant that makes 1 per cent of
Caucasians (and an estimated 10 per cent of Ashkenazi Jews) immune to
HIV infection. It blocks receptors on the surface of cells where the
AIDS virus would otherwise enter. Scientists suspect the trait was
passed down from Europeans who survived medieval smallpox plagues
thanks to the same mutation.

Another variant known to be fairly exclusive to a particular people is
the "Duffy null" mutation in people from sub-Saharan Africa. Penn
State genetic anthropologist Mark Shriver explained that it likely
became prevalent there because it offered protection against a
particular type of malaria, "but it didn't spread widely outside of
Africa."

Yet Dr. Shriver, who by all outward appearances is a white man, happens
to carry it. A scan of his genome suggests that while he is
predominantly European, he is also about 11 per cent West African and 3
per cent native American.

"Race just doesn't exist in a critical line," he said. "It's more
of a gradient."

Dr. Shriver applauds the information flowing in from the HapMap project
(which is freely available on-line), calling it "a revolutionary
tool" for science. But others are not so impressed.

"Basically, it is a total waste of money," Columbia University
geneticist Joseph Terwilliger said.

Dr. Terwilliger argued that by focusing on the most common genetic
mutations, the project would overlook the most specific differences to
be found in any group. It would make "populations look systematically
more similar to one another than they really are."

Medically important traits - such as the HIV-resisting gene type -
could be missed if researchers do not deliberately hone in on the rarer
quirks in each particular racial group.

"Different populations have enormous differences," Dr. Terwilliger
said. "If this were not true, then there is no way we can determine
how we are related and how populations migrated historically.

"You cannot put people neatly in a small number of meaningful
categories like black, white or Asian. That said, Koreans and Chinese
are genetically vastly more similar than either are to Germans."

The controversy around the scientific meaning of race is already
spilling over from the lab to the medical clinic. Researchers continue
to debate definitions, but the age of race-based medicine is upon us.

The U.S. Food and Drug Administration approved the world's first
"ethnic" medication last fall, a heart-failure drug for African
Americans known as BiDil. Pharmaceutical giant AstraZeneca is
developing marketing plans for a lung-cancer drug that flopped in
Caucasians but seems to work for Asians.

No one yet fully understands the actual genetic traits that make these
drugs effective in these groups. And scientists have every reason to
believe people other than blacks or Asians may carry these traits. But
for now, prescriptions for such medications are to be based on little
more than physical appearances and questions about a patient's
heritage.

And this, Prof. Condit argued, could lead to significant risks. Doctors
may end up denying a drug to Caucasians who might benefit from it,
because it is touted to work only in South Asians. Or they might
prescribe a pill to a black person who actually would benefit from some
other treatment. (For example, research has found that as many as 30
per cent of African-American men have a white male ancestor, a fact
attributed to the sexual politics of slavery.)

Prof. Condit has tried to bring the inherent dangers of race-based
science to the attention of the researchers involved. She has published
journal articles, held focus groups and arranged meetings that few
scientists leave their labs to attend. Without careful consideration
and communication, she warned, modern medicine could set race relations
back decades.

She offered this scenario: Imagine a drug marketed only for blacks, a
simple pain reliever, prescribed in the millions. Now imagine that,
like a certain now-notorious pain medication, it turns out to have the
horrible side effect of increasing the risk of heart attacks. Result:
Tens of thousands of North American blacks - and only blacks - die.

"What happens if you get a Vioxx situation with one of these drugs?
And the likelihood of this happening is very high," she said. "But
until there's a catastrophe, people don't want to deal with it. You are
playing with fire."

Those watching the field of modern racial genetics explode are already
concerned.

"If genes predispose groups to certain diseases or health conditions,
might we also find information that hints at more socially loaded
conclusions?" the University of Alberta's Tim Caulfield wondered.

Last summer, Prof. Caulfield was surprised to read an article in the
prestigious journal Science titled, "Peering Under the Hood of
Africa's Runners." It noted that all but six of the 500 fastest times
for the 100-metre dash have come from sprinters of West African
descent, which includes most U.S. blacks. Kenyans, meanwhile, dominate
world records in long-distance races.

According to the report, Swedish physiologists trying to penetrate the
"Kenyan mystique" compared runners from Africa and Scandinavia on
treadmill times, lung capacity, heart rates and body weights. Limb
measurements indicated that the Kenyans carried 400 grams less flesh on
each calf. The report referred to their "birdlike legs," explaining
how Kenyan runners squeeze more power from their oxygen intake, since
"they need less energy to swing their limbs."

Research on West Africa's sprinters, meanwhile, revealed a body type of
heavier "fast-twitch" muscles, versus the lighter "slow-twitch"
muscles of endurance runners, as well as denser bones, narrower hips,
thicker thighs, longer legs and lighter calves. Efforts are now under
way to decode the genetics behind all these traits.

Like Prof. Harpending's paper on Ashkenazi Jews, the report on African
runners presented a positive picture of its subjects, albeit a
stereotypical one. Yet it seemed eerily reminiscent of ugly
19th-century efforts to gauge racial differences with calipers and
cranial measurements.

Prof. Caulfield, who holds the Canada Research Chair in Health Law and
Policy, was mostly concerned about where such research would lead.
Already, he said, an Australian company is cashing in on the notion
that some people are born to run, offering to test a child's genes for
fast- or slow-twitch muscles - "so you know which sport to put your
kid in."

While he said he loathes the idea of restricting scientific research in
a free, democratic society, Prof. Caulfield described the race-based
search for disease genes as a Pandora's box.

Studies are sure to appear on genes linked to complex characteristics
in racial groups, such as athletic or cognitive ability or even
criminal behaviour. But these traits, he stressed, are anything but a
simple story of genetics.

"It's like beauty," he said. "Being beautiful will involve the
interplay of thousands of genes and social factors that dictate at a
given time what is beautiful. It's a very complex story, it involves
culture, socio-economic class, experience. . . . So how do you handle
that information?"

As Penn State's Mark Shriver put it, "It's not that genes for IQ,
athletic ability and musical ability don't exist. But you just can't
tease apart the affect of environment in shaping these abilities."

If people are starting to overestimate the role genes play in shaping
human health and behaviour - and underestimate the huge impact of
experience, environment and social forces - Columbia's Joseph
Terwilliger said that scientists must share the blame.

"In many ways, scientists over-hyped the information in the genome,
or at least what we know about it, to the point where now people are
getting unnecessarily nervous about societal implications," he said.

"The fact is that to get the funding they sold genetic determinism,
which of course is nothing close to reality. And now they are paying
the price."

This year, the journal American Psychologist devoted an entire issue to
the impact race and genetics could have on its field, raising a list of
the difficult questions ahead. It included three papers on the
controversial issue of intelligence, including one commentary arguing
that genes should get more attention in studies of racial intellectual
differences.

For Dr. Harpending, who admitted he would never have "even muttered
in public" his theories about Ashkenazi Jews and intelligence were he
not a senior professor with tenure, this type of conversation cannot
come soon enough.

"There is this massive disconnect between public and private
discourse; between what's said in the public arena and what your
neighbour tells you [about racial groups] over the fence," he said.
"Some of those things are wrong and bigoted, but some of those are
right."

Perhaps. But would Prof. Harpending dare match his Ashkenazi study with
one of India's lowest Hindu caste, the so-called untouchables, who like
European Jews have historically been an isolated society - except, in
this case, relegated to centuries of cleaning latrines?

"One is the mirror image of the other, I suppose," he admitted.
"I would personally find that distasteful. But if I had a theory
about it, I would hope that I would publish it."

If the race debate in science seems sticky now, it's only going to get
worse.

This summer, scientists from all over the world are gathering to
discuss plans for yet another map of the human genome. This one is
based again on a discovery involving Canadian research - and in
scientific terms, it is hard to overstate its significance.

Geneticist Steve Scherer, a senior scientist at Toronto's Hospital for
Sick Children, working with colleagues at Harvard University,
discovered last August that the basic model of simple genetic
inheritance science has clung to for 100 years is wrong: Mom and dad
don't always make equal genetic contributions in the creation of a
child's genome.

Instead, some people might end up with three, four or even more copies
of a gene from one parent, instead of the single copy of each gene
scientists thought each parent always contributed.

The implications could be huge. There might be greater genetic
differences between individuals - and certain populations - than
anyone imagined. Certainly, there are more than the HapMap is charting,
Dr. Scherer said.

Might one ethnic group, for example, carry an overload or an underload
of genes for a particular trait?

"I think it was premature to say that the difference between people
might only be 0.1 per cent," Dr. Scherer said. "Based on what we
know now, it is probably in the 0.2 per cent range. And in the end it
may even be as high as 1 per cent."

Dr. Scherer spent two days last August fielding media calls when the
news first broke. He did most of the interviews by phone, but in a few
cases it was easiest to respond by e-mail.

Then came a call from his Harvard collaborators informing him that one
of those e-mail interviews had been with a writer who worked for a
neo-Nazi website. The writer spun the news as scientific proof of
genetic differences between races - without even misquoting or
twisting Dr. Scherer's words.

"As a geneticist," the 41-year-old Dr. Scherer said, "it's your
worst nightmare."

The HapMap's Tom Hudson in Montreal has had the same one. A colleague
recently referred him to an Internet hate site that declared the HapMap
would finally prove the biological basis of race.

"It made me queasy, because they actually name the name of my friend,
my colleague in Boston. And they actually say, 'He's going to prove
us right.'

"I didn't understand what I was reading when I first read it," Dr.
Hudson said. "I never read something that was so disgusting."

It wasn't an isolated incident.

Morris Foster, an associate professor of anthropology at the University
of Oklahoma and one of the HapMap's leaders, said researchers are
tracking racist sites for references to the HapMap, which logs 20,000
downloads a week from its public database. They have amassed quite a
collection.

Not only do the hate sites keep abreast of what HapMap information has
become available (such as recent data on Japanese and Nigerians), but
they anxiously await findings that will help unveil genetic traits
linked to such things as crime and cognitive ability by race.

"Once it is scientifically demonstrated," one web contributor
writes, "that will be the beginning of the end for the
Marxist-egalitarian argument over race. Personally, I can't wait."

Even Western Ontario's infamous J. Philippe Rushton has seized upon
modern genetics as an opportunity to make his case again, in the
company of Arthur Jensen, a University of California psychology
professor who argues that race determines IQ.

This month, the unpopular scholars have the lead article in the journal
Psychology, Public Policy and Law , presenting 60 pages of evidence
arguing that genes explain 50 per cent of the IQ differences between
races, in which Asians rank higher than whites and whites higher than
blacks.

(The publisher, the American Psychological Association, invited
scientists to rebut the paper in the same issue.)

And yet, despite all the social hazards of modern genetics, Dr. Scherer
said scientists should not "have to fear discussing their results of
their research, so long as they are open-minded and listen to
criticisms and comments from others, including the public.

"I always wonder what Darwin would have done in today's world."

The ultimate test, Dr. Harpending pointed out, lies not with
researchers, but with the public.

He described projects under way involving genes potentially associated
with controversial behaviours such as sexual promiscuity, adultery and
family abandonment.

"A number of things are coming down the pipe," he said, "that we
are going to have to figure out how to cope with as a decent and moral
society."

Carolyn Abraham is The Globe and Mail's medical reporter.

http://www.theglobeandmail.com/servlet/story/RTGAM.20050618.wxrace0618/BNStory/Front/
Sbharris[atsign]ix.netcom.com - 19 Jun 2005 05:44 GMT
>>Henry Harpending is about to titillate the world's conspiracy theorists
with one of the most politically incorrect academic papers of the new
millennium.

Why, he and his colleagues at the University of Utah asked, have Jews
of European descent won 27 per cent of the Nobel Prizes given to
Americans in the past century, while making up only 3 per cent of the
population? Why do they produce more than half the world's chess
champions? And why do they have an average IQ higher than any other
ethnic group for which there's reliable data, and nearly six times as
many people scoring above 140 compared with Europeans?

Prof. Harpending suggests that the reason is in their bloodline -
it's genetic. <<

COMMENT:

Well, it's NOT the most politically incorrect thing you can think of,
just the most politically incorrect which has to be seriously answered
in the media. You can't accuse the man of anti-semitism, which has
become THE most politically incorrect sin of modern times.  This is
actually flattering to Jews, though naturally it makes them very
uncomfortable. Not least because they half believe it already, and so
does everybody else.

The idea that all races of humans are exactly on equal footing when it
comes to intelligence and culture, was pioneered by that darling of
cultural relativism and the Left, Franz Boas, an anthropologist who was
of course a Jew. Since then, it's become academic scripture. Anything
that doesn't argue that humans are tabual rasa, and soley the products
of their cultural environments, is held these days to be wrong.
Including the idea that Askenazi Jews or Chinese might naturally and
genetically be better at math, music, and language.  Float that idea in
academia these days, and you'll just get a sort of sorrowful shrugging
(from Jewish professors and their Chinese grad students). Sure, you
might not be a regular skinhead with views like that, but obviously
you've blown a fuse somewhere, because anytime one group of people is
smarter, that means some other group of people has got to be dumber,
and we all know where that leads. Straight to Auschwitz, of course!

If was really good a few years ago when the human genome was all
sequenced and there didn't seem to be room enough in it to put in all
those racial difference that we seem to see by eye, and in
pharmacology. So maybe they're all in our imaginations?  But this year,
we found out that a lot of the difference in dog breeds are cause by
short tandem repeats in DNA, of the kind that don't show up as big
changes in sequencing, but which have drastic effects on gene function.
So gee, maybe the difference between the chihuahua and the St Bernard
IS in their genes after all!  Maybe beagles ARE really stupider than
Border Collies. And it's not just their owners....

And what will we find when we start looking at the human genome that
way?  

SBH
Brucebo - 19 Jun 2005 06:46 GMT
> >>Henry Harpending is about to titillate the world's conspiracy theorists
> with one of the most politically incorrect academic papers of the new
[quoted text clipped - 10 lines]
> Prof. Harpending suggests that the reason is in their bloodline -
> it's genetic. <<

 The specific gist of the the paper is "overclocking" genes, that is,
genes that convey enhanced intelligence at a potential cost in physical
disability, for example in homozygous individuals.  On example is Tay
Sachs genes may be intellectually stimulating in heterozygotes, while
it is lethal in homozygotes.  The authors propose testable hypotheses.

. . .

> If was really good a few years ago when the human genome was all
> sequenced and there didn't seem to be room enough in it to put in all
[quoted text clipped - 11 lines]
>
> SBH

Well there's the HapMap project at
http://www.hapmap.org/thehapmap.html.en  There's also a lot of
discussion at the Gene Expression blog at http://www.gnxp.com

-Bruce
Mark & Steven Bornfeld - 23 Jun 2005 19:39 GMT
>>>>Henry Harpending is about to titillate the world's conspiracy theorists
>>
[quoted text clipped - 41 lines]
>
> -Bruce

    What I don't understand is the suggestion that abnormalities in brain
lipid metabolism may be connected to intelligence.
    Has anyone actually tried to find out if all those Jewish Nobel
laureates had the trait for Tay Sachs, Gaucher's or other genetic
disease with higher prevalence in Ashkenazic jews?
    Since I've been genetically tested and found to be negative for Tay
Sachs, Gaucher's, CF, etc. does it mean that I'm dumb?  Or does it mean
that if I'm smart, it's just dumb luck?

Steve

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718-258-5001

Sbharris[atsign]ix.netcom.com - 23 Jun 2005 19:55 GMT
>>Has anyone actually tried to find out if all those Jewish Nobel
laureates had the trait for Tay Sachs, Gaucher's or other genetic
disease with higher prevalence in Ashkenazic jews? <<

No, but if they did, they'd have to dig a lot of them up.

SBH
Mark & Steven Bornfeld - 23 Jun 2005 20:11 GMT
>>>Has anyone actually tried to find out if all those Jewish Nobel
>
[quoted text clipped - 4 lines]
>
> SBH

    The whole premise of this theory sounds pretty speculative to me.

Steve

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718-258-5001

Sbharris[atsign]ix.netcom.com - 23 Jun 2005 21:43 GMT
COMMENT:

Well, the Tay-Sachs part, yes.  But the idea that inbred groups of
people might differ from each other in their (various) mental abilities
as much as they do appearance, height, and physical abilities, doesn't
seem that far-fetched to me. As I said, after all, beagles are pretty
dumb. And border collies, on average, are pretty darn smart.

SBH
Mark & Steven Bornfeld - 23 Jun 2005 21:53 GMT
> COMMENT:
>
[quoted text clipped - 5 lines]
>
> SBH

    Not at all far fetched.  But if the researcher was suggesting that
genetic errors of lipid metabolism were related to intelligence, he need
not have posed this as a racial issue.
    I haven't read the original paper--I first heard of this in the NY
Times.  Cynical as I am, it's hard for me to think the researcher wasn't
consciously courting controversy by posing this as a racial issue rather
than specifically relating it to lipid metabolism.

Steve

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718-258-5001

Brucebo - 23 Jun 2005 23:26 GMT
The authors are focusing on "overclocking" genes because they are
specific, known and identifiable, leading to a testable and falsifiable
hypothesis, i.e., "real science" as apposed to Boasian bull sh.t.  The
authors do not imply that "overclocking" genes are the only mechanism
whereby intelligence might be enhanced through natural selection.

-Bruce  bbowen@pacbell.nnnnnnnnnnnnnnnnnet
outrider - 24 Jun 2005 00:34 GMT
Bruce can you get the study for us?



Zee
Steven Bornfeld - 24 Jun 2005 00:55 GMT
> The authors are focusing on "overclocking" genes because they are
> specific, known and identifiable, leading to a testable and falsifiable
[quoted text clipped - 3 lines]
>
> -Bruce  bbowen@pacbell.nnnnnnnnnnnnnnnnnet

    Don't know what overclocking genes are.  In any case, they might well
have tested Tay Sachs and Gauchers' carriers, and not identified by
ethnicity.

Steve

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Cut the nonsense to reply

Brucebo - 24 Jun 2005 21:47 GMT
>     Don't know what overclocking genes are.

  It's a metaphor.  "Overclocking" refers to running the clock
oscillator of a CPU at a rate faster than what the chip is designed
for, for the purpose of extracting extra performance, at the risk of
possible malfuction, overheating and/or degradation over time.

>  In any case, they might well
> have tested Tay Sachs and Gauchers' carriers, and not identified by
> ethnicity.

You get more accurate results when compairing two people with and
without the genes from the same ethnic group, rather than disparate
groups.  The control group shares much of the other genes.  That's why
twin studies are often used. Comparing an Ashkenazi with a Tay-Sachs
gene with a Bantu without would be meaningless.

-Bruce
Mark & Steven Bornfeld - 25 Jun 2005 14:13 GMT
>>    Don't know what overclocking genes are.
>
[quoted text clipped - 14 lines]
>
> -Bruce

    It may well be.  But my point is that the study may be of the Tay-Sachs
gene, but all the headlines (perhaps not the original study--do you
know?)  don't say that Tay-Sachs carriers are extra smart--they say that
Jews have a genetic leg-up in the intelligence department.  Why would
they say that, unless they were looking to be deliberately inflammatory
(or, perhaps less cynically, just looking for more publicity for their
study)?

Steve

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718-258-5001

DZ - 25 Jun 2005 18:31 GMT
>> In any case, they might well have tested Tay Sachs and Gauchers'
>> carriers, and not identified by ethnicity.
[quoted text clipped - 4 lines]
> why twin studies are often used. Comparing an Ashkenazi with a
> Tay-Sachs gene with a Bantu without would be meaningless.

But what did the study actually do? They did not do any comparisons
that would involve IQ as a variable whatsoever. As far as I can tell
the entire argument is:

1) Jewish ancestry is linked to higher expected IQ than say general
Caucasian ancestry.

2) Certain alleles candidate for lipid metabolism disorders are in
higher frequency in Jews.

3) These alleles are at somewhat higher frequency than predicted by
simple bottleneck with drift models (therefore selection is
hypothesized).

That's all. The connection between IQ and these alleles is based on
speculations of their involvement in neurological processes AND on the
entirely dubious argument that since the frequency of alleles is
higher than predicted by the neutral model they must account for the
high IQ.

DZ
bae@cs.toronto.no-uce.edu - 24 Jun 2005 15:45 GMT
>COMMENT:
>
[quoted text clipped - 3 lines]
>seem that far-fetched to me. As I said, after all, beagles are pretty
>dumb. And border collies, on average, are pretty darn smart.

I agree that inbred groups are likely to have disproportionate ratios
of some alleles, but you need pretty heavy selection to get the kind of
uniformity you see in a dog breed.  You can see a little of such
selection where a population has lived in a particular climate for a
very long time, but it's selection for only a few traits, like heat
loss or resistance to malaria.  These ethnic groups are generally as
diverse as anybody else otherwise, as can be seen from blood group and
HLA markers.

You can't select for everything, when creating a breed.  Border collies
were selected for their intelligence and willingness to cooperate with
the shepherd, alertly noting his signals and obeying them.  Beagles
were selected for acute sense of smell and willingness to follow a scent.
These traits are exaggerated forms of behaviours found in wolves.  Beagles
are useless as sheepdogs, and border collies are lousy trackers.  Note
that desirable traits have to be continually maintained by selection --
most working breeds of dogs have separate populations now, show dogs
selected for their conformity to the written standards for appearance
and working dogs, which are selected to maintain the behaviour traits
for which the breed was developed.

To create a uniform population like a dog breed, you start with a very
small initial population, usually only a few individuals, inbreed very
closely (parent to child, parent to grandchild), and select strongly
for desired traits, discarding all but a few best matches to your ideal
when deciding which animals will produce the next generation.  These
conditions don't occur naturally, especially not in humans.  Even small
populations on islands and religious groups that practice complete
endogamy avoid inbreeding as much as possible and don't practice
artificial selection.  They begin to show unusual rates of a few
genetic traits, usually undesirable ones, after many generations, and a
very small island population may start to have a sort of family look
about them, but they are nowhere near as uniform as an animal breed.

Jews are a very poor candidate for a human "race" or "breed".  It's
long been established that genetically they are closely similar to the
ethnicities they live among, and for obvious reasons.  There's some
effect due to migrations in the past thousand years, as Jews were
expelled from most western European countries in late medieval times
and moved east and south.  But even visually, eastern European Jews
look like eastern Europeans, North African Jews look like North
Africans and Chinese Jews look like Chinese.  Blood group data
demonstrate this very clearly.

As for all these Nobel laureate Jews, well, I can assure you that there
is no shortage of Jews who are not so smart.  If a culture very
strongly values a trait, members of that culture will be pushed to
develop that trait in themselves, and rewarded for doing so, and those
individuals with talent in that direction will have the opportunity to
excel.  This applies to any talent or trait -- intellectual ability,
athletic ability, aggressiveness, artistic talent, religious
tendencies, whatever.  The Scandinavians are the same people they were
800 years ago, but they are no longer noted for the ability to go into
berserk rages and slaughter the defenseless in droves oblivious to
their own safety, although this was a prized and widely expressed
talent in Viking times.

This notion that Tay-Sachs is associated with intelligence is just hand
waving, as far as I can see.  Until there's some actual data, we have
no reason to believe it's anything but wishful thinking.  I've also
heard the theory that Tay-Sachs is associated with resistance to
tuberculosis, another link for which there's no evidence.  I suspect
that Tay-Sachs is just another bad recessive trait that hasn't had
enough selection against over long enough time to be eliminated.
Against the Third World like conditions that prevailed in Europe until
a few generations ago -- large families and high mortality rates in
infants and young children -- deaths from Tay-Sachs would be lost in
the noise.

People don't select themselves for desirable traits, after all.  Even
if a culture strongly values some trait, and rewards men who excel at
it with greater opportunities to contribute to the next generation,
most everybody, and almost all women, still marry and have children.
You may want to marry the person who best displays the ideal of your
culture, but you'll settle for what you can get.  You don't make any
progress in developing a genetically uniform population, like a
livestock breed, that way.

Jews, like any disfavored group, tell just-so stories to comfort
themselves.  One is to point out that in medieval Europe, people with
noted intellectual talents would enter monasteries and leave the gene
pool, presumably making the general population stupider than the Jews.
This of course ignores the fact that most medieval Europeans were
peasants who had no opportunity to express scholarly abilities in
monasteries or elsewhere, and most people who became monks or nuns did
so for other reasons and found reading a real chore, if they ever
became literate at all.  Another just-so story is that the prohibition
on pork is a wise tradition, or even an example of special divine
consideration, for preventing trichinosis.  Well, an injunction to boil
water before drinking it, or the inside word on smallpox vaccination
would have saved orders of magnitude more lives that trichinosis could
ever have taken.

Incidentally, most cases of Tay-Sachs now occur amongst people of
French Canadian origin, because Jews are using modern techniques to
select against it in themselves.  I sincerely doubt that the Jews are
getting stupider, or the Quebecois are getting smarter.

(Btw, it would be easy to test this theory that Tay-Sachs heterozygotes
have better intellectual abilities than others.  Find a bunch of
high school students who are self-identifying Jews and offer free
Tay-Sachs testing in exchange for a peek at their SAT scores.  It
shouldn't be difficult to find many thousands of subjects, and if
there's a real correlation, there should be a significant difference
in Tay-Sachs rates between the upper and lower tenth percentile.
Betcha there isn't, but nobody knows until somebody does the research.)
Sbharris[atsign]ix.netcom.com - 25 Jun 2005 20:20 GMT
>>Jews are a very poor candidate for a human "race" or "breed".  It's
long been established that genetically they are closely similar to the
ethnicities they live among, and for obvious reasons.  There's some
effect due to migrations in the past thousand years, as Jews were
expelled from most western European countries in late medieval times
and moved east and south.  But even visually, eastern European Jews
look like eastern Europeans, North African Jews look like North
Africans and Chinese Jews look like Chinese.  Blood group data
demonstrate this very clearly. <<

COMMENT

It might if we're comparing Ashkenazi to Saphardics, say, rather than
comparing Ashkenazi to Europeans. But the hypothesis of "Jewish
intellegence" has really only been advanced ONLY for the Ashkenazi
Jews, and in that case of course there's a lot of evidence for
inbreeding. How can you possibly have a population where one in 30
people carries an allele like Tay-Sachs which hardly anybody else has,
without a lot of inbreeding (or a founder effect from a very small
group of individuals, followed by pretty stringent conservation).
Basically, you can't keep a 1 in 30 incidence of an allele which nobody
else has at even 1% of that, EXCEPT by inbreeding.  And there are at
least half a dozen of these genetic diseases, all arrising from
different recessive alleles, which ONLY show up in more than extreme
rarity, Eastern Europe included, except in Ashkanzi Jews. That's ALSO
just impossible without a lot of inbreeding.

By the the way, I don't think Ashkenazi Jews look just like Eastern
Europeans. Moreover, this group was in France in the time of
Charlemagne and later Germany, and only later moved East, and they
don't look typically French or German, either, at least to my eye.

I agree that the hypothesis that Ashekenazi intellegence is associated
with heterzygosity for Askenazic genetic diseases, is handwaving before
we collect the SAT stats and stuff like you sugggest. And it seems
rather unlikely that genes that screw up DNA repair (on cluster of
Askenzazic diseases) have anything to do with intelligence.

But here's the funny thing which promped the suggestion. Askenzaic Jews
don't have just have a big incidence of ONE recessive gene which alters
cell managment of sphingolipids, which would be expected to have a
disporportionate impact on brain development. They have FOUR of such
diseases for this SAME pathway: Tay-Sachs, Gaucher, Niemann-Pick, and
mucolipidosis type IV.  As far as I can tell, all involve completely
separate genes. This is a tremendously fishy fact, and NOBODY has a
good explanation for it. The nearest thing *I* can think of to compare
it to, is the fact that the gene that codes for the amino acid change
that causes sickle cell anemia (and trait) is known to have arisen
separately at least twice in the population subject to heavy pressure
to develop hemoglobin genetic variations to cope with the pressure of
malaria. If Ashkenzi, who were certainly inbred, and who were certainly
under heavy selective pressure as Europe's moneylenders for a
millennium, managed to develop four separate mutations in their brain
sphingolipid metabolism, and conserve all four, then YOU tell ME what's
going on. I think the brain/intelligence hypothesis is a lot better
story than the TB one. On that, at least, we agree.

SBH
bae@cs.toronto.no-uce.edu - 29 Jun 2005 15:26 GMT
>It might if we're comparing Ashkenazi to Saphardics, say, rather than
>comparing Ashkenazi to Europeans.

Make that "other Europeans", okay?

>But the hypothesis of "Jewish
>intellegence" has really only been advanced ONLY for the Ashkenazi
[quoted text clipped - 9 lines]
>rarity, Eastern Europe included, except in Ashkanzi Jews. That's ALSO
>just impossible without a lot of inbreeding.

Well, Tay-Sachs now occurs more frequently in people of Quebecois
origin than in Jews (although the incidence of carriers is lower), so
it's quite possible that it has or had some benefit to heterozygotes.
The Quebecois are not particularly inbred.  In the period before the
urbanization and mass immigration that started about 60 years ago they
would have been comparable to most rural European populations, with the
interesting exception that they were about 30% Cree in ancestry.  If
we're going to wave hands here, we can plump for the proposed anti-TB
effect of Tay-Sachs, since TB was a big killer then (100 years ago,
about one death in four was caused by TB, usually in people of
reproductive age) and people of (gee, at this point I don't know what
to call them without being castigated) western hemisphere ancestry are
more susceptible to TB and other eastern hemisphere diseases than
Europeans, who have been exposed to and selected by them for
millennia.

Tay-Sachs may have entered the Quebec population from Ashkenazi Jews
who came to Quebec as traders and mostly married into the Cree population.
So there's some founder effect there, with perhaps the coincidental effect
of Tay-Sachs being carried along on the disease-resistance benefit
conferred by the rest of the European genome.

Btw, next to Ashkenazic Jews and Quebecois, Tay-Sachs is most common
in the Cajuns of Louisiana (French, French-Canadian and African in
origin) and some *Amish* groups.  Sort that out!

>By the the way, I don't think Ashkenazi Jews look just like Eastern
>Europeans. Moreover, this group was in France in the time of
>Charlemagne and later Germany, and only later moved East, and they
>don't look typically French or German, either, at least to my eye.

Well, people who look Jewish to you may look Jewish, but a lot of people
of Ashkenazi Jewish origin don't particularly look Jewish, so you might
not think of them as such, so there's some selection bias here.  A lot
of people of Ashkenazi origin are no longer practicing Jews, either, which
may make them less visible to you.

>I agree that the hypothesis that Ashekenazi intellegence is associated
>with heterzygosity for Askenazic genetic diseases, is handwaving before
>we collect the SAT stats and stuff like you sugggest. And it seems
>rather unlikely that genes that screw up DNA repair (on cluster of
>Askenzazic diseases) have anything to do with intelligence.

And it's a politically loaded question, too, so I think it's best not to
handwave too hard about desirable traits and historically (and currently)
persecuted groups until there's some Actual Data.  Unlike malaria resistance,
"intelligence" is very hard to quantify and to separate from environmental
(cultural) effects.

>But here's the funny thing which promped the suggestion. Askenzaic Jews
>don't have just have a big incidence of ONE recessive gene which alters
[quoted text clipped - 14 lines]
>going on. I think the brain/intelligence hypothesis is a lot better
>story than the TB one. On that, at least, we agree.

This same population was exposed to the absolutely worst consequences
of urbanization in the ghettos of Europe for about 1500 years, unlike
the general European population that wasn't significantly urbanized
until the 19th century in western Europe and the 20th in eastern
Europe.  For all we know, heterozygosity for those undesirable traits
might have something to do with better protection for the CNS during
the high fevers of infectious diseases, which would have been rampant
in overcrowded ghettos under medieval standards of sanitation.
(On the spot handwaving here.)  After all, most Jews weren't
moneylenders; they had the usual sorts of far more humble occupations,
other than farmer, which was forbidden to them for most of that
period, and having marginally higher IQ, if that's the case, was not
likely to be the kind of selective advantage that sickle cell is in a
bad malaria zone, where few but heterozygotes attain reproductive age.
Under filthy, overcrowded conditions, offspring of moneylenders and
shoemakers alike are mostly going to die of dysentery in infancy,
or whichever epidemic disease comes through every few years or the
endemic diseases that persist under such conditions, no matter how
smart their parents are or aren't.

At any rate, it's mysterious, and worthy of further study.  The
intelligence hypothesis is easily and inexpensively tested, so why
doesn't somebody do it?  Most young people of Ashkenazi origin want to
be tested for Tay-Sachs trait, there are plenty of Jewish high schools
and high schools in Jewish areas, the test for Tay-Sachs trait is
readily available and while SAT scores are not IQ tests, they are
reasonable surrogates for the kind of academic-success intelligence
proposed, especially with a large sample of many thousands.  With a
little more funding, they can toss in tests for the less common conditions
you mention above, and get more papers at the same time for minor
additional outlay.  But once you have the results, what do you do with
them?  It's an emotionally and socially loaded issue.

Gosh, maybe the association is with stubbornness -- people who will
stick with a set of beliefs for which they are persecuted and forced to
live in abominable conditions for generation after generation, when
they could convert, assimilate and have their grandchildren disappear
into the general gene pool.  So the less stubborn people, without the
trait, gradually deplete the normal allele by leaving, and the
Ashkenazi Jews end up concentrating the stubbornness genes... (Can
barely keep my eyes open in the wind from the handwaving here.  Just-so
stories are so easy to construct. You can replace stubbornness with
self-righteousness, intensity of religious belief, delusions of divine
preference, ancestral curses or whatever you like here, too.  Note that
cluelessness might be a good candidate, except it argues against the
hypothesis proposed.  I better quit this political incorrectness before
I have to defend myself by claiming membership in the allegedly
deprecated group.)

Btw, what's the current word on the persistence of cystic fibrosis at a
rate of 1 carrier in 40 in people of northern European origin?  Last I
heard they had dropped the stock anti-TB hypothesis and had some data
to support the notion that sperm cells carrying the trait had a
selective advantage in fertilizing eggs.  There's a symptomatically
similar condition due to a mutant gene for alpha trypsinogenase
inhibitor that persists because women with the trait are somewhat more
fertile due to cervical mucus that's more permeable to sperm.  These
things can be appallingly subtle.
outrider - 29 Jun 2005 16:30 GMT
This group also has extremely high rates of familial
hypercholesterolemia.
Terri - 29 Jun 2005 22:15 GMT
>>It might if we're comparing Ashkenazi to Saphardics, say, rather than
>>comparing Ashkenazi to Europeans.
[quoted text clipped - 40 lines]
> in the Cajuns of Louisiana (French, French-Canadian and African in
> origin) and some *Amish* groups.  Sort that out!

History coming back to bite us. The cases in Louisiana have been traced
back to the expulsion/forcible conversion of Spain's Jewish population
under Ferdinand and Isabella. Jews who converted didn't get to change
their genetic make-up, so when the descendants of these now Roman
Catholic Spaniards went adventuring in the New World, they brought their
genes with them. More than 4 centuries later, this made itself manifest
when certain Cajun communities developed very high incidence of what
appeared to be Tay-Sachs but couldn't be because Tay-Sachs is a problem
of Ashkenazi Jews, not Louisiana Cajuns, right? Guess what? Genetic
testing showed Tay-Sachs beyond any doubt. Some geneologist finally
found the connecting links. I suspect you'd find the same kind of origin
in Quebec...

>>By the the way, I don't think Ashkenazi Jews look just like Eastern
>>Europeans. Moreover, this group was in France in the time of
[quoted text clipped - 96 lines]
> fertile due to cervical mucus that's more permeable to sperm.  These
> things can be appallingly subtle.
Sbharris[atsign]ix.netcom.com - 29 Jun 2005 23:18 GMT
>>Btw, what's the current word on the persistence of cystic fibrosis at a
rate of 1 carrier in 40 in people of northern European origin?  Last I
heard they had dropped the stock anti-TB hypothesis and had some data
to support the notion that sperm cells carrying the trait had a
selective advantage in fertilizing eggs.  <<

COMMENT:

Was there ever a TB hypothesis for cystic fibrosis?  One that makes far
more sense is a defect in chloride-ion transport is protective against
toxin induced diarrheal diseases, which kill infants by stimulating the
very same chloride pump. Lots writen on this.

http://serendip.brynmawr.edu/biology/b103/f02/web1/emyers.html

SBH
bae@cs.toronto.no-uce.edu - 01 Jul 2005 19:04 GMT
>>>Btw, what's the current word on the persistence of cystic fibrosis at a
>rate of 1 carrier in 40 in people of northern European origin?  Last I
[quoted text clipped - 10 lines]
>
>http://serendip.brynmawr.edu/biology/b103/f02/web1/emyers.html

Thanks for the ref, Steve.  I may have misremembered about a TB
connection.  TB was such a big killer of young adults in the late
19th and early 20th century (1 in 4) that attributing TB resistance
to any mysteriously retained deleterious allele is a popular form
of handwaving, like bubonic plague resistance (also 1 in 4, over a
much shorter time span).
 
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