My latest Mind and Matter column for the Wall
Street Journal is on the prospect of de-extinction, especially the
Extinct species are gone forever. Or are they? For some time now
the dream of re-creating something like a mammoth from its DNA has
been floating about on the fringes of the scientific world (and in
movies like “Jurassic Park”) without being taken seriously.
Now, however, the science is getting serious. A new
organization, Revive and Restore, under the auspices of the
Long Now Foundation (a hip think tank), with the help of National
Geographic and TED (a hip conference organizer), is setting out its
stall at TEDxDeExtinction, a meeting in Washington, D.C., on March
The founders of Revive and Restore aren’t mainstream scientists,
but they’re not people to be taken lightly, either. Stewart Brand
and Ryan Phelan are a husband-and-wife team with a track record of
starting unusual but successful organizations—in his case, the
Whole Earth Catalog and the Global Business Network; in hers, the
consumer-focused startups Direct Medical Knowledge and DNA Direct.
They’ve attracted the interest of the pioneering Harvard University
DNA sequencing and synthesis expert George Church.
Their argument is that it’s time to start tentatively trying
de-extinction and thinking through its ethical and ecological
implications. There are already projects under way to revive
extinct subspecies like the European aurochs (a type of wild
cattle) and the Pyrenean ibex, or bucardo. In the latter case, when
the last female (Celia) was killed by a falling tree in 2000, her
tissue was cloned. At least one fetus survived to term in a
surrogate mother goat, but it died soon after birth.
A full species that’s been extinct for decades like the
thylacine (Tasmanian tiger) or the passenger pigeon—the last one of
which, Martha, died in the Cincinnati Zoo 99 years ago—will be a
taller order, since the DNA from long dead specimens is fragmented.
Yet Ben Novak, a young researcher working with the ancient-DNA
expert Beth Shapiro at the University of California, Santa Cruz,
has extracted passenger pigeon DNA from the toe pad of a museum
specimen and sequenced it. Dr. Church hopes to use one of the newly
invented letter-by-letter gene-replacement techniques, such as
Talens or Crispr, to transform the genome of a related species
called the band-tailed pigeon into that of a passenger pigeon.
There’s little doubt that this will succeed. Until recently the
next step looked harder—to persuade another species to lay a
passenger pigeon egg. But now Michael McGrew of the Roslin
Institute in Scotland and colleagues at Dubai’s Central Veterinary
Research Laboratory have extracted chicken germ cells and put them
into ducks so that the duck produced chicken sperm. The “chimeric”
duck then mated with a chicken and produced normal chicken chicks.
So a pair of chimeric ducks or chickens could in theory produce
passenger pigeon chicks.
Of course, that’s where the ecological and ethical fun starts.
Some ecologists are opposed to the whole idea, fearing that it will
make people less concerned about species extinction. Mr. Brand
counters that the project should redouble the urgency of preserving
habitats for extinct species to reoccupy. Others worry that the
passenger pigeons won’t have parents to teach them where to
migrate. But the restorers of endangered species like whooping
cranes and California condors have surmounted such hurdles.
Hand-reared cranes are taught to migrate following microlight
Ms. Phelan emphazises that there’s plenty of time to get it
right. It will take years to re-create the birds perfectly and more
years to build their population through captive breeding. Further
time will be needed to ensure that their old habitat (and the
inevitable regulators) will welcome them. Perhaps the passenger
pigeon might turn into a pest. It was once probably the most
numerous bird in the world, with flocks that darkened the skies for
hours. What a nice problem that would be to have again.