[Marxism] How Genetics Is Changing Our Understanding of ‘Race’

Louis Proyect lnp3 at panix.com
Fri Mar 23 18:30:30 MDT 2018


On 3/23/18 8:25 PM, hari kumar via Marxism wrote:
> Hi: I would be grateful of the whole article in some way could be posted -
> especially interested in this issue. Would that be possible? Thanks for
> considering,
> Cheers Hari Kumar

How Genetics Is Changing Our Understanding of ‘Race’
Gray Matter

By DAVID REICH MARCH 23, 2018

In 1942, the anthropologist Ashley Montagu published “Man’s Most 
Dangerous Myth: The Fallacy of Race,” an influential book that argued 
that race is a social concept with no genetic basis. A classic example 
often cited is the inconsistent definition of “black.” In the United 
States, historically, a person is “black” if he has any sub-Saharan 
African ancestry; in Brazil, a person is not “black” if he is known to 
have any European ancestry. If “black” refers to different people in 
different contexts, how can there be any genetic basis to it?

Beginning in 1972, genetic findings began to be incorporated into this 
argument. That year, the geneticist Richard Lewontin published an 
important study of variation in protein types in blood. He grouped the 
human populations he analyzed into seven “races” — West Eurasians, 
Africans, East Asians, South Asians, Native Americans, Oceanians and 
Australians — and found that around 85 percent of variation in the 
protein types could be accounted for by variation within populations and 
“races,” and only 15 percent by variation across them. To the extent 
that there was variation among humans, he concluded, most of it was 
because of “differences between individuals.”

In this way, a consensus was established that among human populations 
there are no differences large enough to support the concept of 
“biological race.” Instead, it was argued, race is a “social construct,” 
a way of categorizing people that changes over time and across countries.

It is true that race is a social construct. It is also true, as Dr. 
Lewontin wrote, that human populations “are remarkably similar to each 
other” from a genetic point of view.

But over the years this consensus has morphed, seemingly without 
questioning, into an orthodoxy. The orthodoxy maintains that the average 
genetic differences among people grouped according to today’s racial 
terms are so trivial when it comes to any meaningful biological traits 
that those differences can be ignored.

The orthodoxy goes further, holding that we should be anxious about any 
research into genetic differences among populations. The concern is that 
such research, no matter how well-intentioned, is located on a slippery 
slope that leads to the kinds of pseudoscientific arguments about 
biological difference that were used in the past to try to justify the 
slave trade, the eugenics movement and the Nazis’ murder of six million 
Jews.

I have deep sympathy for the concern that genetic discoveries could be 
misused to justify racism. But as a geneticist I also know that it is 
simply no longer possible to ignore average genetic differences among 
“races.”

Groundbreaking advances in DNA sequencing technology have been made over 
the last two decades. These advances enable us to measure with exquisite 
accuracy what fraction of an individual’s genetic ancestry traces back 
to, say, West Africa 500 years ago — before the mixing in the Americas 
of the West African and European gene pools that were almost completely 
isolated for the last 70,000 years. With the help of these tools, we are 
learning that while race may be a social construct, differences in 
genetic ancestry that happen to correlate to many of today’s racial 
constructs are real.

Recent genetic studies have demonstrated differences across populations 
not just in the genetic determinants of simple traits such as skin 
color, but also in more complex traits like bodily dimensions and 
susceptibility to diseases. For example, we now know that genetic 
factors help explain why northern Europeans are taller on average than 
southern Europeans, why multiple sclerosis is more common in 
European-Americans than in African-Americans, and why the reverse is 
true for end-stage kidney disease.

I am worried that well-meaning people who deny the possibility of 
substantial biological differences among human populations are digging 
themselves into an indefensible position, one that will not survive the 
onslaught of science. I am also worried that whatever discoveries are 
made — and we truly have no idea yet what they will be — will be cited 
as “scientific proof” that racist prejudices and agendas have been 
correct all along, and that those well-meaning people will not 
understand the science well enough to push back against these claims.

This is why it is important, even urgent, that we develop a candid and 
scientifically up-to-date way of discussing any such differences, 
instead of sticking our heads in the sand and being caught unprepared 
when they are found.

To get a sense of what modern genetic research into average biological 
differences across populations looks like, consider an example from my 
own work. Beginning around 2003, I began exploring whether the 
population mixture that has occurred in the last few hundred years in 
the Americas could be leveraged to find risk factors for prostate 
cancer, a disease that occurs 1.7 times more often in self-identified 
African-Americans than in self-identified European-Americans. This 
disparity had not been possible to explain based on dietary and 
environmental differences, suggesting that genetic factors might play a 
role.

Self-identified African-Americans turn out to derive, on average, about 
80 percent of their genetic ancestry from enslaved Africans brought to 
America between the 16th and 19th centuries. My colleagues and I 
searched, in 1,597 African-American men with prostate cancer, for 
locations in the genome where the fraction of genes contributed by West 
African ancestors was larger than it was elsewhere in the genome. In 
2006, we found exactly what we were looking for: a location in the 
genome with about 2.8 percent more African ancestry than the average.

When we looked in more detail, we found that this region contained at 
least seven independent risk factors for prostate cancer, all more 
common in West Africans. Our findings could fully account for the higher 
rate of prostate cancer in African-Americans than in European-Americans. 
We could conclude this because African-Americans who happen to have 
entirely European ancestry in this small section of their genomes had 
about the same risk for prostate cancer as random Europeans.

Did this research rely on terms like “African-American” and 
“European-American” that are socially constructed, and did it label 
segments of the genome as being probably “West African” or “European” in 
origin? Yes. Did this research identify real risk factors for disease 
that differ in frequency across those populations, leading to 
discoveries with the potential to improve health and save lives? Yes.

While most people will agree that finding a genetic explanation for an 
elevated rate of disease is important, they often draw the line there. 
Finding genetic influences on a propensity for disease is one thing, 
they argue, but looking for such influences on behavior and cognition is 
another.

But whether we like it or not, that line has already been crossed. A 
recent study led by the economist Daniel Benjamin compiled information 
on the number of years of education from more than 400,000 people, 
almost all of whom were of European ancestry. After controlling for 
differences in socioeconomic background, he and his colleagues 
identified 74 genetic variations that are over-represented in genes 
known to be important in neurological development, each of which is 
incontrovertibly more common in Europeans with more years of education 
than in Europeans with fewer years of education.

It is not yet clear how these genetic variations operate. A follow-up 
study of Icelanders led by the geneticist Augustine Kong showed that 
these genetic variations also nudge people who carry them to delay 
having children. So these variations may be explaining longer times at 
school by affecting a behavior that has nothing to do with intelligence.

This study has been joined by others finding genetic predictors of 
behavior. One of these, led by the geneticist Danielle Posthuma, studied 
more than 70,000 people and found genetic variations in more than 20 
genes that were predictive of performance on intelligence tests.

Is performance on an intelligence test or the number of years of school 
a person attends shaped by the way a person is brought up? Of course. 
But does it measure something having to do with some aspect of behavior 
or cognition? Almost certainly. And since all traits influenced by 
genetics are expected to differ across populations (because the 
frequencies of genetic variations are rarely exactly the same across 
populations), the genetic influences on behavior and cognition will 
differ across populations, too.

You will sometimes hear that any biological differences among 
populations are likely to be small, because humans have diverged too 
recently from common ancestors for substantial differences to have 
arisen under the pressure of natural selection. This is not true. The 
ancestors of East Asians, Europeans, West Africans and Australians were, 
until recently, almost completely isolated from one another for 40,000 
years or longer, which is more than sufficient time for the forces of 
evolution to work. Indeed, the study led by Dr. Kong showed that in 
Iceland, there has been measurable genetic selection against the genetic 
variations that predict more years of education in that population just 
within the last century.

To understand why it is so dangerous for geneticists and anthropologists 
to simply repeat the old consensus about human population differences, 
consider what kinds of voices are filling the void that our silence is 
creating. Nicholas Wade, a longtime science journalist for The New York 
Times, rightly notes in his 2014 book, “A Troublesome Inheritance: 
Genes, Race and Human History,” that modern research is challenging our 
thinking about the nature of human population differences. But he goes 
on to make the unfounded and irresponsible claim that this research is 
suggesting that genetic factors explain traditional stereotypes.

One of Mr. Wade’s key sources, for example, is the anthropologist Henry 
Harpending, who has asserted that people of sub-Saharan African ancestry 
have no propensity to work when they don’t have to because, he claims, 
they did not go through the type of natural selection for hard work in 
the last thousands of years that some Eurasians did. There is simply no 
scientific evidence to support this statement. Indeed, as 139 
geneticists (including myself) pointed out in a letter to The New York 
Times about Mr. Wade’s book, there is no genetic evidence to back up any 
of the racist stereotypes he promotes.

Another high-profile example is James Watson, the scientist who in 1953 
co-discovered the structure of DNA, and who was forced to retire as head 
of the Cold Spring Harbor Laboratories in 2007 after he stated in an 
interview — without any scientific evidence — that research has 
suggested that genetic factors contribute to lower intelligence in 
Africans than in Europeans.

At a meeting a few years later, Dr. Watson said to me and my fellow 
geneticist Beth Shapiro something to the effect of “When are you guys 
going to figure out why it is that you Jews are so much smarter than 
everyone else?” He asserted that Jews were high achievers because of 
genetic advantages conferred by thousands of years of natural selection 
to be scholars, and that East Asian students tended to be conformist 
because of selection for conformity in ancient Chinese society. 
(Contacted recently, Dr. Watson denied having made these statements, 
maintaining that they do not represent his views; Dr. Shapiro said that 
her recollection matched mine.)

What makes Dr. Watson’s and Mr. Wade’s statements so insidious is that 
they start with the accurate observation that many academics are 
implausibly denying the possibility of average genetic differences among 
human populations, and then end with a claim — backed by no evidence — 
that they know what those differences are and that they correspond to 
racist stereotypes. They use the reluctance of the academic community to 
openly discuss these fraught issues to provide rhetorical cover for 
hateful ideas and old racist canards.

This is why knowledgeable scientists must speak out. If we abstain from 
laying out a rational framework for discussing differences among 
populations, we risk losing the trust of the public and we actively 
contribute to the distrust of expertise that is now so prevalent. We 
leave a vacuum that gets filled by pseudoscience, an outcome that is far 
worse than anything we could achieve by talking openly.

If scientists can be confident of anything, it is that whatever we 
currently believe about the genetic nature of differences among 
populations is most likely wrong. For example, my laboratory discovered 
in 2016, based on our sequencing of ancient human genomes, that “whites” 
are not derived from a population that existed from time immemorial, as 
some people believe. Instead, “whites” represent a mixture of four 
ancient populations that lived 10,000 years ago and were each as 
different from one another as Europeans and East Asians are today.

So how should we prepare for the likelihood that in the coming years, 
genetic studies will show that many traits are influenced by genetic 
variations, and that these traits will differ on average across human 
populations? It will be impossible — indeed, anti-scientific, foolish 
and absurd — to deny those differences.

For me, a natural response to the challenge is to learn from the example 
of the biological differences that exist between males and females. The 
differences between the sexes are far more profound than those that 
exist among human populations, reflecting more than 100 million years of 
evolution and adaptation. Males and females differ by huge tracts of 
genetic material — a Y chromosome that males have and that females 
don’t, and a second X chromosome that females have and males don’t.

Most everyone accepts that the biological differences between males and 
females are profound. In addition to anatomical differences, men and 
women exhibit average differences in size and physical strength. (There 
are also average differences in temperament and behavior, though there 
are important unresolved questions about the extent to which these 
differences are influenced by social expectations and upbringing.)

How do we accommodate the biological differences between men and women? 
I think the answer is obvious: We should both recognize that genetic 
differences between males and females exist and we should accord each 
sex the same freedoms and opportunities regardless of those differences.

It is clear from the inequities that persist between women and men in 
our society that fulfilling these aspirations in practice is a 
challenge. Yet conceptually it is straightforward. And if this is the 
case with men and women, then it is surely the case with whatever 
differences we may find among human populations, the great majority of 
which will be far less profound.

An abiding challenge for our civilization is to treat each human being 
as an individual and to empower all people, regardless of what hand they 
are dealt from the deck of life. Compared with the enormous differences 
that exist among individuals, differences among populations are on 
average many times smaller, so it should be only a modest challenge to 
accommodate a reality in which the average genetic contributions to 
human traits differ.

It is important to face whatever science will reveal without prejudging 
the outcome and with the confidence that we can be mature enough to 
handle any findings. Arguing that no substantial differences among human 
populations are possible will only invite the racist misuse of genetics 
that we wish to avoid.

David Reich is a professor of genetics at Harvard and the author of the 
forthcoming book “Who We Are and How We Got Here: Ancient DNA and the 
New Science of the Human Past,” from which this article is adapted.



More information about the Marxism mailing list