January/February 2019^ DISCOVER^11
ON AN INTERCONTINENTAL FLIGHT several
years ago, Harris Lewin decided
to ind the common ancestor of all
complex life on Earth, from slime
molds to his fellow passengers. As a
professor of evolution and ecology
at the University of California,
Davis, Lewin knew what he’d have
to do to travel back billions of years
in evolutionary time and study this
enigmatic progenitor: generate a DNA
sequence for every species alive today.
It would be a worldwide equivalent of
the Human Genome Project (HGP),
which fully mapped the DNA of our
species in 2003.
Lewin took out a pencil to calculate
the cost. “I couldn’t believe the
number,” he recalls. At $3 billion, the
estimate was well within the price
range of today’s moonshot science,
and considerably less, adjusted for
ination, than the cost of sequencing
the human genome in the 1990s.
Back on the ground, Lewin emailed
his friend John Kress, a botanist
then serving as the Smithsonian
Institution’s undersecretary for science.
In November 2015, Kress convened
a meeting of leading scientists at the
Smithsonian, where Lewin proposed
to sequence all 1.5 million known
eukaryotes — organisms with a cellular
nucleus, the trait that distinguishes
complex life from microbes — within
a single decade. Since none of them
could come up with a reason why it
couldn’t be done, they started scheming
ways the data would justify the expense,
bolstering everything from medicine
to conservation.
Now, labs around the world are iring
up their DNA sequencers. With severalhundred million dollars of seed funding
and a plan published in Proceedings
of the National Academy of Sciences
outlining “the most ambitious proposal
in the history of biology,” the Earth
BioGenome Project (EBP) is underway.
But to sequence an organism’s DNA,
you have to get your hands on it irst.
Zoos and botanical gardens, plus places
like the Smithsonian, offer a head start
with their collective 500,
species. Even better, some
15,000 complete genomes are
already published, mostly by
smaller programs on which
EBP is modeled. For instance,
the 1KP initiative sequenced
1,000 plant genomes, and
Genome 10K is pushing to
sequence 10,000 vertebrates.
Lewin thinks perhaps
500,000 more species samples
can be scooped up by avid
citizen scientists, but gathering
the last half-million will take serious
innovation, such as sample-collecting
drones and submersibles.
Data processing is another hurdle.
EBP’s initial phase concentrates on
quality, generating about 9,000 highly
detailed “reference genomes.” Using
current tech, that task would take more
than 150 years. University of British
Columbia biologist Michael Deyholos,
who helped lead 1KP, lauds EBP’s
ambition but adds, “I don’t think the
timelines are at all realistic.”
Yet the HGP suggests seemingly
impossible tasks may be perfectly
feasible. Demand and inancial resources
are great technological accelerators.
In the mid-1980s, when researchers
conceived the HGP, they knew they’dCataloging Life
have to sequence 3 billion DNA base
pairs, but they could sequence only
300 per week. “But people said, ‘OK,
we can sequence DNA,’ ” Lewin says.
“They started to ask, ‘What if ?’ ”
The HGP went on to contribute
an estimated $1 trillion to the U.S.
economy. It helped experts improve
medical diagnoses and discover new
drugs. EBP could bring similar gains,
particularly to the world of medicine.
“Eighty percent of pharmaceuticals
are derived from natural products,”
Lewin observes. Often these are based
on adaptations humans lack but other
organisms have, such as microbial
resistance. Researchers might enlist
newly sequenced organisms or
their genes to manufacture these
substances, as well as novel materials
and less-toxic fuels.
But even just knowing
what’s out there, from the
Amazon’s canopy to the
ocean oor, is valuable to
ecologists contending with
climate change and mass
extinction. Populations with
low genetic diversity can
be relocated to minimize
inbreeding. Scientists
may uncover genes that
foster resilience — like one
recently found to make
some coral strains more
tolerant to heat.
But as much as Lewin wants to
save the world, he can’t help but dwell
on the basic science. “In 10 years,
I’ll be 71,” he says. “By that time,
I hope we’ll have reconstructed the
ancestral genome of eukaryotes,”
which can be uncovered only by
iguring out what genetic material
all complex life shares. “Having the
entire set of blueprints will also allow
us to understand the rules of natural
selection, and then we can understand
evolutionary trajectories.”
Lewin’s ambitions are nothing less
than to reveal the past and predict the
future — both likely to be essential
tools for navigating the present.ERIC ISSELEE/SHUTTERSTOCK — JONATHON KEATS
Biologists’ most ambitious plan is just firing up.
BIG IDEAGathering
the last
half-million
species
samples
will take
serious
innovation.