Last Updated:April 17. 2008 11:24PM
Published: April 18. 2008 3:30AM

Far from their native Asian homes, just outside of Moulton, 12 tigers are housed at the Animal House Zoological Society Sanctuary.

Carolyn Atchison, the sanctuary's owner and animal advocate, said that nearly two weeks ago, the streak of cats got a new addition, Shasa, a preemie born during a storm.

Atchison said the circumstances behind how the mother became pregnant was an accident, but that the kitten was being nursed to health.

When asked about the genetic lineage of the cats, what many advocates say is a crucial link to maintaining the fast dwindling species, Atchison said, "I couldn't even begin to trace back where they came from."

That may not be necessary.

Many captive tigers, such as those in zoos, circuses and sanctuaries, are purebred subspecies of tigers and may harbor genetic diversity lost in nature, according to new research, an important discovery for tiger conservationists.

Tigers such as the ones kept by Atchison may hold unexpected genetic diversity, needed for conservation of dwindling tiger populations.

By comparing the genetic makeup of 134 wild tigers, an international team of researchers found that nearly half of 105 captive tigers they tested from 14 countries represented one of five purebred subspecies of tiger.

Subspecies, for example, would include Bengal and Indo-Chinese tigers, animals that can mate but normally in nature do not because of geographic separation.

Shu-Jim Luo, an author from the National Cancer Institute in Maryland, said that the new genetic testing tool, "if applied to tigers of uncertain background, may considerably increase the number of purebred tigers for conservation management."

The research was published Thursday in Current Biology.

Tigers, which numbered more than 100,000 in the wild in the 1900s, have dwindled to as few as 3,000 in 2007, according to the research led by Stephen O'Brien, of the National Cancer Institute in Maryland.

Captive tiger populations, however, are flourishing with an estimated 15,000 to 20,000 captive tigers worldwide.

The researchers said that even though their results may overestimate purebred captive tigers, even if substantially less captive tigers are purebred, their conservation value would be increased.

The results weren't surprising for Brian Werner, founder and executive director of the Tiger Missing Link Foundation, an organization focused on determining the genetics of undocumented captive tigers as a tool for conservation.

"I was the guy who was preaching this 10 years back," Werner said of extending tiger conservation efforts beyond the wild and into the private sector. "The captive tigers are the missing link to saving the native tiger population."

Zoos traditionally use zoo animals for breeding, which can lead to inbreeding, Werner said.

He speculated that 35 to 50 percent of captive animals may be purebred subspecies, from preliminary genetic data from Therion International, of a tiger database that the organization keeps.

Werner said the study suggested that the three tiger subspecies considered extinct "could be floating around the private sector."

"The exciting thing is that the tiger isn't going to disappear off the planet if we can manage them."

Trevor Stokes can be reached at 740-5728 or trevor.stokes@timesdaily.com.