for a world in which a $50 DNA test can predict your odds of
earning a PhD or forecast which toddler gets into a selective
Plomin, a behavioral geneticist, says that’s exactly what’s
decades genetic researchers have sought the hereditary factors
behind intelligence, with little luck. But now gene studies have
finally gotten big enough—and hence powerful enough—to zero in
on genetic differences linked to IQ.
year ago, no gene had ever been tied to performance on an IQ
test. Since then, more than 500 have, thanks to gene studies
involving more than 200,000 test takers. Results from an
experiment correlating one million people’s DNA with their
academic success are due at any time.
discoveries mean we can now read the DNA of a young child and
get a notion of how intelligent he or she will be, says Plomin,
an American based at King’s College London, where he leads a
long-term study of 13,000 pairs of British twins.
outlined the DNA IQ test scenario in January in a paper titled “The
New Genetics of Intelligence,” making a case that parents
will use direct-to-consumer tests to predict kids’ mental
abilities and make schooling choices, a concept he calls
of now, the predictions are not highly accurate. The DNA
variations that have been linked to test scores explain less
than 10 percent of the intelligence differences between the
people of European ancestry who’ve been studied.
Technology Reviewfound that aspects of
Plomin’s testing scenario are already happening. At least three
online services, including GenePlaza and DNA Land, have started
offering to quantify anyone’s genetic IQ from a spit sample.
are holding back. The largest company offering
direct-to-consumer DNA health reports, 23andMe, says it’s not
telling people their brain rating out of concern the information
would be poorly received.
educators contacted byMIT
Technology Reviewreacted with alarm to
the new developments, saying DNA tests should not be used to
evaluate children’s academic prospects.
idea is we’ll have this information everywhere you go, like an
RFID tag. Everyone will know who you are, what you are about. To
me that is really scary,” says Catherine Bliss, a sociologist at
the University of California, San Francisco, and author ofa
bookquestioning the use of genetics in
world where people are slotted according to their inborn
ability—well, that isGattaca,”
says Bliss. “That is eugenics.”
psychologists, IQ tests measure something called “g”—the
general factor of intelligence. People who are better at math,
spatial reasoning, verbal ability, and other skills that tests
can measure have higherg.
that’s not all. Thegfactor
is strongly correlated with income, happiness, health, and life
to be a good thing all around. To Plomin it’s the
“omnipotent variable” in life.
also highly heritable. Comparisons of twins, both identical and
fraternal, separated at birth or raised together, had shown that
genetics must account for more than half of intelligence—a huge
effect for genes. The rest is due to your schools, your diet,
and other environmental factors.
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which specific genes are responsible? The search did not go well
at first. Plomin failed to discover any links when he looked at
the genomes of 7,900 children in 2010. He later became involved
in a misadventure involving a Chinese sequencing company, BGI,
to which he supplied the DNA of more than a thousand American
got derailedafter news reports accused
the Chinese of hatching a plot to breed “genius
gene hunt finally paid off in May 2017. A Dutch-led study of the
genetic makeup of 78,308 people who’d taken tests (including
2,825 of Plomin’s twins) zeroed in on variations in 22 genes
linked to IQ scores. By this March, the tally had rapidly risen
to 199,000 people and 500 genes. Plomin says a forthcoming
report will establish links to 1,000 genes.
genetic variable found so far has only a tiny effect, either
weakly increasing IQ on average or weakly decreasing it. The
trick to turning the discoveries into a personal DNA IQ test?
Simply add up all the pluses and minuses you find in a specific
was quick to sign up. Last year, he spit in a tube and had his
DNA scores calculated by his research center. Now, during talks,
he presents his genetic rankings. He’s on the high end of the
risk for arthritis (he has some), lower than average for
depression, and in the 94th percentile for being overweight.
Plomin, whose weight sometimes nears 240 pounds, the genetic
prediction explains his lifelong battle with starches and
sweets. “People will say, ‘Oh, there’s nothing you can do—you’re
a genetic fatty,’ but it helps me to know. It’s a constant
battle of the bulge,” he says.
course, he knows his percentile rank for predicted academic
achievement, too. “It’s 99-point-something—it’s embarrassing,”
you Einstein or Bozo?
scientists toldMIT Technology
Reviewthey don’t believe genetic IQ
tests can tell individuals anything useful and aren’t sure why
Plomin is saying they will.
will never be able to look into someone’s DNA and say your IQ
will be 120,” says Danielle Posthuma, who led the big 2017 IQ
study. “I don’t think it makes much sense to use it that way. I
would just give people an IQ test.” Posthuma says her main
interest is in discovering how the brain works at a basic level,
where finding genes associated with intelligence can help.
however, points out that IQ tests with colored blocks barely
work for little kids, failing to accurately capture how
they will do on tests later in life. Your DNA, on the other
hand, is there from the day you are born and doesn’t change.
Early in life, Plomin says, DNA may already provide a better
intelligence prediction than any test does.
the issue is accuracy—or lack of it. Right now, the polygenic
scores capture only a fraction of the genetic determinants of
intelligence and none of the environmental ones. That means the
predictions remain fuzzy.
is clear from Plomin’s own data. His center calculated polygenic
scores for hundreds of the twins he’s followed since their birth
and whose DNA it has on file. He then compared the gene scores
with how well the twins (now in their 20s) had done on a UK-wide
exam that everyone takes as a teenager.
one against the other, the result looks more like a slightly
elongated cloud of dots than a straight line. That is, the DNA
predictions and the test scores tended to line up, though not
perfectly. Some with low DNA scores had gotten great test
results as teens. Others had bombed despite the promise in their
Aaron Panofsky, a sociologist of science with the University of
California, Los Angeles, that’s a huge problem. With this
technology, you could end up branding an Einstein as a Bozo, and
vice versa. “Is the claim that you are going to have
kindergarteners spit in test tubes and get some traction on
their achievement when they graduate high school? Well, in
aggregate, it looks like it will be better than rolling dice,”
says Panofsky. “But what if we want to determine ifyourkid
should be in the gifted or remedial program?”
it comes to using DNA tests in the real world, Panofsky says, “I
don’t think they thought about it very hard.”
scores for sale
Technology Reviewfound that genetic IQ
assessments are already being offered by websites that provide
information to people who’ve previously had their DNA measured
by 23andMe or Ancestry.com.
for example, can upload their 23andMe data and pay $4 extra to
access an “Intelligence App,” which rates their DNA using data
from the big 2017 study on IQ genes.
shows users where their genes place them on a bell curve from
lower to higher IQ. A similar calculation is available fromDNA
you be among the first to pick your kids’ IQ? As machine
learning unlocks predictions from DNA databases, scientists
say parents could have choices never before possible.
results come with disclaimers saying the results don’t mean much
yet, because they predict only about 5 points of IQ. “I hope
people are not getting it thinking that this is a true measure
of their intelligence,” says Alain Coletta, a bioinformatics
scientist and the founder of GenePlaza.
says he put up the app “for fun.”
far, the major consumer DNA testing companies have steered clear
of intelligence reports. “There are obviously some concerns
about how it gets used and gets talked about,” says James Lu,
cofounder of California-based Helix, a leading app store for DNA
the history of eugenics, big companies have to fear being called
out as Nazis and racists. What's more, customers might not be
pleased to receive a prediction of less than average
the testing company 23andMe, which has studied the DNA of more
than five million people and offers consumers reports on 21
traits, including everything from the chances of having a cleft
chin to the likelihood of developing a bald spot. Of these trait
reports, 16 are calculated employing polygenic scores.
23andMe doesn’t offer any reports about intellectual faculties.
And that’s not because it doesn’t have the data. It does.
Because it surveys customers on how long they stayed in school,
a proxy for intelligence, the Google-backed company has been
playing a supporting role in the search for intelligence genes
by contributing its customers’ DNA data to the largest of the
why not tell customers? In response toMIT
Technology Review’s question, 23andMe gave us a
statement. “Educational attainment is something we have looked
at previously but are not currently pursuing for our
product for several reasons,” said Shirley Wu, director of
product science for 23andMe. “One being the pitfalls of
potential misinterpretation of such a report.”
it’s still taboo to talk about, some medical scientists are
trying to figure out how to use the polygenic intelligence
the smartest embryo from an IVF dish, choose the best
sperm donor, or discover fetuses at high risk for an expanded
menu of cognitive disorders, including autism.
Conley, a sociologist at Princeton University, says as soon as
the IQ predictions reach the double digits—something that could
occur very soon—we will need to have a “serious policy debate”
about such “personal eugenics.” One concern is that IVF is
expensive. That could lead to a situation in which the wealthy
end up using IQ-test technology to pick kids with select genes
while the poor don’t, leading to an unequal society that Conley
calls a “genotocracy.”
scores are getting better at predicting intelligence, risks
for common diseases, and more.
suggest that genetic models of intelligence will be used to
compare races, ethnic groups, or people from different parts of
the world. Inan
editorialabout the genetics of race
published in theNew
York Timeson March 23, Harvard
University biologist David Reich cited the new genetic IQ
predictors and cautioned that “all traits influenced by genetics
are expected to differ across populations.”
warning was implicit: differences in IQ could be due to genes,
not circumstance, and polygenic scores might prove it.
psychologists working in genetics, the breakthroughs of the last
year have brought DNA prediction of behavior much closer to
practical use. In the public square, though, they face a throng
of skeptics, who say their science is misleading or who disavow
are in a situation when you mention you work in intelligence,
people say, “Oh, you can’t measure that.’ What is intelligence?”
says Stuart Ritchie, a psychologist at the University of
Edinburgh. “The debate we need to be having is on the actual
ethics of doing this genetic prediction, whether it’s measuring
kids to predict how they will do in school or selecting
say the great question will be when it is acceptable to prejudge
people from DNA profiles. We’d probably want to tell people if
their DNA says they are at risk for addiction, for example.
Maybe they won’t pick up that first cigarette. But what does it
mean to tell parents their kid is at risk of being smart or
Plomin, at least, the answer is already clear. He says polygenic
scores for IQ will further reveal the role of intelligence in
determining people’s salaries, their choice of partners, and
even the structure of society. People will want to know.
says he’s writing a book, titledBlueprint,
that he thinks is “going to piss a lot of people off” by arguing
that DNA is the “major systematic force in making people who