Nature: Test-tube panda offers hope for a dying species

Chinese scientists have taken the first step towards creating a

test-tube giant panda.

As one of the world's rarest animals heads towards extinction in the wild, Teresa Poole finds that the breakthough may have come too late.

On 4 August, Chinese scientists at the Laboratory of Genetic and Embryo Engineering on Endangered Wildlife received a call telling them a 17-year-old female giant panda had died from disease.

The loss of a captive giant panda is an event almost enough to send China into national mourning, but in this case her death brought the potential for a scientific breakthrough. Since the beginning of this year, the laboratory had been equipped to attempt the world's first test-tube panda fertilisation. The only ingredients missing were female panda eggs.

The team led by one of China's foremost panda experts, Zhang Anju, removed the dead panda's ovaries as quickly as possible. "The egg we took out from the dead panda was immature, so we cultured it first in the laboratory," said Mr Zhang. The egg was then fertilised with sperm from the panda semen bank in Chengdu, capital of Sichuan province in China's south-west. "We cultured it for more than 10 hours and it began to divide, growing into the shape of a dumb-bell. This really is the first successful in vitro fertilisation of the panda both in China and abroad," he said.

Sichuan is the world centre for panda research, and over the past week it has hosted an international gathering of panda experts, panda lovers, and panda pundits. The Chengdu meeting takes place every four years and the academic symposium, attended this year by 200 experts from China and overseas, is a chance for an update on new research. Much of the focus this year was on advances in breeding technique for an animal which is notoriously sex-shy.

As Mr Zhang explained this week, faulty equipment - or bad luck - resulted in the carbon dioxide concentration in the incubator rising too high. This killed the fertilised egg. "If this had not happened, the cell could have grown into an embryo and been transplanted into a female panda," said Mr Zhang, who has spent 30 years conducting panda research.

The laboratory, which he heads, now plans to do further experiments on other large, rare animals, such as the black bear, "which are more easily available than the giant panda ... after these experiments are successful, we will take eggs from living pandas who have lost the ability to bear cubs", he said. The test-tube panda may yet become a reality.

While reproductive short-comings are a challenge, the main threat to the survival of the panda is mankind's destruction of its natural habitat. Since 1949, one-third of the forest cover in Sichuan, where most pandas live, has been felled. there are now only an estimated 1,000 pandas left in the wild. The panda communities which have survived are often cut off from each other, so that in-breeding is a major threat to genetic diversity.

Mr Zhang and his colleagues want to see much more effort put into protecting the pandas' habitat, so that any artificially bred pandas have somewhere to go and live. And over the next few years, China plans to build "green passageways", linking areas set aside for the panda so that the occasionally randy pandas have a better chance to meet.

Pandas are fussy eaters and the death of large tracts of bamboo, their staple, is another serious threat. From 1983 to 1996 as many as 183 pandas suffering from illness or malnutrition were found in the wild. Panda poaching also remains a threat, despite the death penalty for anyone caught peddling a panda skin.

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