Page 6 - De-Extinction: The Science of Bringing Lost Species Back to Life

90 DEEXTINCTION

advanced age, her body no longer had eggs, so the scientists
saved cells from her ovaries and uterus instead.
Nola may have died, but her cells live on, preserved in a
bitterly cold place known as the Frozen Zoo.

BANKING ON THE FUTURE

The Frozen Zoo, which is part of the Institute for Conservation
Research, is 30 miles (48 km) north of San Diego. It occupies
a windowless room with a sign on the wall reading “Frozen
Zoo.” In the room sit half a dozen large metal tanks. At the
bottom of each tank is a pool of liquid nitrogen. Suspended
over the pool are towers of plastic boxes. Each box is filled
with rows of plastic vials. Inside each vial is the tissue of an
endangered species.
In all, the tanks at the Frozen Zoo hold ten thousand tissue
samples from nearly one thousand different species. The
samples include cell cultures (cells taken from animals and
grown in the laboratory), eggs, sperm, and embryos. Another
set of tanks in another building holds a duplicate set of all
these cells. Having two sets of cells ensures that the tissue
won’t be lost if the power goes out for any reason. A power
outage at one building would shut down the machines and
thaw and destroy the cells.
As of 2016, only one of the species whose cells are
in storage at the frozen zoo is extinct. That species is the
Hawaiian po’ouli (Melamprosops phaeosoma), or black-faced
honeycreeper, a bird last seen in the wild in 2004. Scientists
expect that as the global extinction crisis intensifies, more of
the species in the Frozen Zoo will join the po‘ouli as extinct
species. When Nola the white rhino died in 2015, her kind
took one step closer to extinction.