5-Animals: Biotech the latest defense in animal-extinction fight
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TITLE: Biotech the Latest Defense in Animal-Extinction Fight
SOURCE: National Geographic, USA, by Sharon Guynup
DATE: Jan 16, 2003
------------------ archive: http://www.gene.ch/genet.html ------------------
Biotech the Latest Defense in Animal-Extinction Fight
Later this year, reproductive biologist Betsy Dresser will check some
rather extraordinary luggage on a flight from New Orleans to Kenya: Two
thermoses containing about 50 bongo embryos, cryogenically frozen at -385
F (-232 C) in liquid nitrogen. Hopefully, these embryos will develop into
healthy calves that will repopulate bongo herds - endangered antelope
that are rapidly disappearing from their African range.
Upon arrival at the 10,000 acre (4,047 hectare) Mt. Kenya Game Ranch,
Dresser and her team will implant these bongo embryos into about 25
surrogate eland mothers that have received three weeks of hormone
injections - like those given women preparing for in-vitro fertilization
(IVF). After a few weeks, the eland will be pregnancy tested - and the
researchers will wait out the 11-month incubation period.
Dresser, director of the Audubon Institute Center for Research of
Endangered Species (AICRES) in New Orleans, is a pioneer in "cross-
species embryo transfer," an experimental method of breeding endangered
species with the help of their more-plentiful - or domestic - relatives.
"Nobody has ever done this (embryo transfer) in the wild before," she said.
As Earth's wild places vanish and the numbers of animals facing
extinction rises, the fight to save dwindling wildlife is expanding on a
new front: in the laboratory. Researchers are adapting techniques like
artificial insemination, cloning, in vitro fertilization and inter-
species embryo transfer for use in threatened species.
Dresser has successfully "incubated" bongo calves in eland mothers before
in captivity, with fresh, not frozen, embryos. This current project
follows her 20 years of reproductive work with endangered species -
including the birth of the first "test-tube" gorilla in 1995 when Dresser
was with the Cincinnati Zoo.
"There is a rapidly growing interest in assisted reproduction
technologies in conservation," said Oliver Ryder, a geneticist at the San
Diego Zoo's Center for Reproduction of Endangered Species (CRES).
For some at-risk species, biotech conservation represents the last chance
to preserve precious genetic diversity, a benchmark of species health and
well-being. Toward this end, zoos have become genetic repositories for
cryogenically frozen eggs, embryos, sperm and tissue.
The Frozen Zoo
The first so-called "frozen zoo" was created in 1975 by Kurt Benirschke,
a visionary physician who switched from his human practice to work with
endangered species at the San Diego Zoo, studying gene pools and genetic
diseases made prevalent by inbreeding.
Today, in zoos around the world, these deep-freeze tanks act as a high-
tech Ark, housing cells from the planet's most endangered animals,
including chimps, cheetahs, pandas, California condors and hundreds more.
As a result, long-dead animals are now becoming parents from the grave,
with their precious DNA still circulating in the gene pool.
"The real goal is the management of the eroding gene pools of endangered
species," says Ryder.
Researchers are mapping familial relationships between animals and
breeding both captive and wild animals through "arranged marriages" to
maximize genetic vigor.
There are species that desperately need help from captive situations -
such as the Sumatran rhino. "We can't save it in the wild," said Alan
Rabinowitz, director of Science and Exploration at the Bronx-based
Wildlife Conservation Society (WCS). "We just cannot keep up with hunters
following a single animal for months, going after its horn. There are
species like that where captive technologies and breeding is crucial."
But captive breeding is not always easy. Many animals are disoriented by
living in the wrong climate or social system, or being squeezed into
small "habitats" in the presence of humans.
Scientists and keepers try to help animals breed naturally. But often,
researchers do not even know how normal mating takes place. "We're
missing a lot of the basic information on the biology of most animals,"
said George Amato, Director of the Conservation Genetics Program at WCS.
So zoos and conservation parks across the US and abroad are developing
costly, hi-tech reproductive research programs. By combining assisted
breeding techniques with wildlife management and reintroduction of
captive-bred animals, they hope to boost wild populations and genetic
There are a few early success stories. This year, researchers from the
Smithsonian National Zoo produced their hundredth black-footed ferret
through artificial insemination, animals that were on the precipice of
extinction. They are being returned to their former habitat in the West.
"The black-footed ferret and the California condor are two species that
would be extinct now without these programs," said Amato.
At AICRES, sand hill cranes are produced through artificial insemination,
incubated, and raised by researchers costumed as cranes to prevent human
imprinting. They are reintroducing 20 of the birds each year to the
Mississippi Sand Hill Crane Refuge in Pascagoula. The endangered flock
now numbers over 100.
Some plans are more elaborate. Steven Monfort, a veterinarian at the
Smithsonian National Zoological Park's Conservation & Research Center in
Front Royal, Va., is conducting habitat surveys in Niger and Chad to find
a place to reintroduce a "world herd" of scimitar-horned oryx, a type of
Zoos from around the world will contribute either female oryxes or oryx
sperm to create the widest-possible genetic mix. "Without this type of
multi-institutional cooperation, captive populations can't play much of a
role in conservation of wild populations," said Monfort.
Cloning Comes to Conservation
Cloning, too, has come to conservation. CRES is collaborating with
Advanced Cell Technology in Worcester, Mass. to clone endangered banteng,
a species of Asian cattle. Eleven milk cows on an Iowa farm are currently
pregnant with banteng babies.
Dresser's team is fine-tuning the cloning of small cats like the African
wildcat, as well as the largest: tigers. They are also working with
banteng and antelope species.
China is developing a program to clone pandas - using rabbits as
surrogate mothers for panda cubs, which are only a few inches long at birth.
Critics argue that expensive biotech programs siphon money away from the
real goal of wildlife protection in the animals' native habitats. Without
proper conservation, suitable habitat may disappear, leaving nowhere to
put these animals conceived in Petri dishes.
"As a whole, people have got to look at biotech as a backup system, not
as the driving force in conservation," said Rabinowitz.
But many animals hover on the brink of extinction in the wild despite
conservation efforts. Protecting these species is such a massive, complex
problem that many agree it is critical to throw as many strategies at it
"I don't believe one thing will save these species," said Dresser. "This
technology will help form a safety net, but habitat conservation is critical."
"I think the future will thank us for what we can save," said Ryder.