DELPHINE LEE24 SCIENCE NEWS | March 13, 2021FEATUREI
t’s been two decades since the Human Genome Project first
unveiled a rough draft of our genetic instruction book. The
promise of that medical moon shot was that doctors would
soon be able to look at an individual’s DNA and prescribe
the right medicines for that person’s illness or even prevent
certain diseases.
That promise, known as precision medicine, has yet to be ful-
filled in any widespread way. True, researchers are getting clues
about some genetic variants linked to certain conditions and
some that affect how drugs work in the body. But many of those
advances have benefited just one group: people whose ancestral
roots stem from Europe. In other words, white people.
Instead of a truly human genome that represents every-
one, “what we have is essentially a European genome,” says
Constance Hilliard, an evolutionary historian at the University
of North Texas in Denton. “That data doesn’t work for anybody
apart from people of European ancestry.”
She’s talking about more than the Human Genome
Project’s reference genome. That database is just one of many
that researchers are using to develop precision medicine strat-
egies. Often those genetic databases draw on data mainly from
white participants. But race isn’t the issue. The problem is thatcollectively, those data add up to a catalog of genetic variants
that don’t represent the full range of human genetic diversity.
When people of African, Asian, Native American or Pacific
Island ancestry get a DNA test to determine if they inherited
a variant that may cause cancer or if a particular drug will
work for them, they’re often left with more questions than
answers. The results often reveal “variants of uncertain signifi-
cance,” leaving doctors with too little useful information. This
happens less often for people of European descent. That dis-
parity could change if genetics included a more diverse group
of participants, researchers agree (SN: 9/17/16, p. 8).
One solution is to make customized reference genomes for
populations whose members die from cancer or heart disease
at higher rates than other groups, for example, or who face
other worse health outcomes, Hilliard suggests.
And the more specific the better. For instance, African
Americans who descended from enslaved people have geo-
graphic and ecological origins as well as evolutionary and
social histories distinct from those of recent African immi-
grants to the United States. Those histories have left stamps
in the DNA that can make a difference in people’s health today.
The same goes for Indigenous people from various parts of theHow to make DNA data work better for everybody By Tina Hesman Saey
Building an
Inclusive Genome
Building an
Inclusive Genome
Building an
race-genetics.indd 24race-genetics.indd 24 2/24/21 10:14 AM2/24/21 10:14 AM