can be a cruel mother. In the history of the Earth extinction has been as constant a reality as the plodding march of evolution. The loss of biodiversity
has been picking up to the pace where some researchers say the world is on the brink of a mass extinction event. And the
primary culprit is man.
I. Inspiration -- Using Stem
Cells to Save Critically Endangered Species
From loss of habitat to poaching to pollution, mankind is making life for
many species -- particularly large animals -- a living hell. In response,
conscious efforts have been made to protect a growing number of endangered
species. However, as Oliver
Ryder, PhD, the director of genetics at the San Diego
Zoo Institute for Conservation Research, comments, "The
best way to manage extinctions is to preserve species and their habitats, but
that's not working all the time."
As a last ditch alternative to traditional conservation techniques,
Professor Ryder's lab has paired with a team led by Jeanne Loring, PhD, professor of developmental
neurobiology at the The Scripps
Research Institute to create stem cells [press release] to help conserve critically endangered species.
The project follows in the footsteps of research to induce "pluripotency" in human skin cells. Pluripotent
cells, better known as stem cells, can differentiate into a variety of cells,
from muscle to bone growing to nerve. There's also increasing hope that
they can be combined with modern cloning techniques to yield viable offspring,
when the resulting stem cell is implanted in the genetically cleansed,
unfertilized egg cell of a closely related species. Efforts to clone prized livestock are already progressing nicely, igniting an inevitable bioethics
But there's little debate about the value of the Scripps Research project.
The project looks to solve two critical problems. One is what to do
when a species becomes totally extinct. In these cases, cloning may hold
the key to restoration efforts. As second problem is how to deal with the
potentially fatal loss of biodiversity in small highly endangered species.
Via gene therapy with stem cells, research hope to reverse the genetic
disease that afflict such populations.
II. Process Proves
Fortuitously Professor Ryder's staff had already been building a bank of
frozen skin cell samples of over 800 endangered species. So when the
project began he had an ample supply of cells to try to induce into
Professors Ryder and Loring focused their efforts on the Drill, one of
the most highly endangered species and the Northern White Rhinoceros, a highly
endangered subspecies. The Northern White Rhino was selected because only
7 specimens are known to be living in the world (two reside at the San Diego
Zoo's wildlife park). The Drill was selected both due to its similarity
to humans and because specimens in captivity frequent suffered from diabetes,
due to limited biodiversity.
Initially the researchers thought they would have to identify new genes
in order to induce pluripotency. But thanks to the marvelous mechanisms of
evolution these mammals -- including the rhino, which is relatively distant in
its relation to man -- used almost the same pluripotency genes as man.
Thus it was shockingly straightforward to create a stem cell population,
though grueling due to the low rate of cell survival that comes inherent to the
current state of induced pluripotency research.
III. Researchers Work to
Create Stem Cell "Zoo"
The successful creation of stem cells opens the door to new research,
including curing diabetes in the Drill and cloning Northern White Rhinos.
In the rhinos' case, researchers believe they may be able to produce both
sperm and egg cells, an approach would likely lead to more viable zygotes than
the traditional approach of cleansing a similar species' egg and injecting
material from the target species' stem cell into it.
The current research has been supported by the Esther O'Keefe
Foundation, the Millipore Foundation, and the California Institute for
Regenerative Medicine. Given the success, the two teams are looking to
expand funding to finance an entire stem cell "zoo".
States Professor Ryder, "Stem cell technology provides some level of
hope that they won't have to become extinct even though they've been completely
eliminated from their habitats. I think that if humankind wants to save this
species, we're going to have to develop new methodologies."
A paper on the work was published [abstract] in the prestigious peer-reviewed journal Nature Methods.
The project is fascinating and could offer a timely accompaniment to
similar ongoing work to create wildlife parks populated by cloned extinct
species, such as the Dodo, Tasmanian Wolf, and Woolly Mammoth.