Panda conceived with frozen sperm

China greets newborn cub

The Associated PressJuly 25, 2009 

— For the first time, a giant panda cub has been born in China after being conceived using frozen sperm, officials announced Friday -- an innovation scientists hope will help the endangered species avoid extinction.

The new cub's birth Thursday means breeders will no longer be forced to rely on semen from China's few virile males, and may even be able to bring in sperm from zoos in San Diego, Mexico City or elsewhere.

That's key to promoting a healthy panda population because too much inbreeding can lead to birth defects that would further threaten the survival of the species.

The new cub, born to You You, a female panda at the Wolong Giant Panda Research Center in southwestern Sichuan, is the tenth born at the breeding facility this year. It was You You's third successful pregnancy.

Panda researchers said Friday that it was the first successful live birth worldwide using frozen panda sperm.

"We did try before but it failed," said Huang Yan, a deputy research technician with the China Panda Preservation Research Center.

He declined to provide specifics but said the Wolong team had improved its thawing techniques, making frozen sperm more viable. Sperm samples are deep-frozen using liquid nitrogen, and in the past, only 20 to 30 percent of the sperm survived. But this time the center managed to raise viability to about 80 percent, he said.

Scientists carried out the artificial insemination in March, and You You was found to be pregnant in June during an ultrasound. The sperm from male Lu Lu had been frozen for "a number of years," said Huang.

Waiting for a name

The sex of the baby panda is not yet clear, so it hasn't been named, Huang said.

The technique, if it can be replicated, will be a boost for panda conservation efforts, said Matthew Durnin, regional science director in the Asia-Pacific and North Asia for The Nature Conservancy, a U.S.-based conservation organization.

"In the past, they're limited to using semen from a few virile, reproductive males. If you're using only one male at a time, you start to get lower and lower diversity. This can help with issues of genetic diversity among your captive population," he said.

Besides preventing inbreeding, genetically diverse panda populations are generally healthier, meaning they will also have a better chance of thriving if released in the wild, he said.

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