[FEL-L] Many captive tigers are of purebred ancestry; finding raises their conservation value

[Brian]

Hello everyone in "tiger land",

Oh this is funny! So WHO has been saying this for the past 15-years?

I think you will all find this of interest, it is a testament to my 
debate (argument) over the past --- oh, say.... 15 years!

Brian Werner
Executive Director
Tiger Missing Link Foundation*

Many captive tigers are of purebred ancestry; finding raises their 
conservation value*

Tigers held in captivity around the world—including those in zoos, 
circuses, and private homes—may hold considerable conservation value for 
the rapidly dwindling wild populations around the world, according to a 
new report published online on April 17th in Current Biology, a Cell 
Press publication. Using a new method for assessing the genetic ancestry 
of tigers, researchers discovered that many apparently "generic" tigers 
actually represent purebred subspecies and harbor genomic diversity no 
longer found in nature.

" Assessment of ‘verified subspecies ancestry’ (VSA) offers a powerful 
tool that, if applied to tigers of uncertain background, may 
considerably increase the number of purebred tigers suitable for 
conservation management," said Shu-Jin Luo, of the National Cancer 
Institute, Frederick. “This approach would be of particular importance 
to tiger subspecies that have suffered severe population decline in the 
wild and/or lack of efficient captive breeding.”

For instance, he said, the Indochinese tiger has been classified as a 
different subspecies from the Malayan tiger, leaving just 14 recognized 
Indochinese individuals in captivity. “Thus,” Luo added, “verification 
of VSA Indochinese tigers, establishment of captive breeding programs, 
and preservation of remaining Indochinese tiger populations in the wild 
should be set as one of the top priorities in the global tiger 
conservation strategy.”

Tigers in general are disappearing rapidly from the wild, from over 
100,000 in the 1900s to as few as 3,000 last year, said the researchers, 
led by Stephen O'Brien also of the National Cancer Institute, Frederick. 
By contrast, captive tigers are flourishing, with 15,000–20,000 
individuals worldwide, outnumbering their wild relatives between five 
and seven to one.

A relatively small portion of the world's captive tigers—some 1,000 
individuals in all—are managed through coordinated breeding programs 
that aim to preserve genetic variability representative of geographic 
and subspecies groupings found in the wild, the researchers said. The 
rest are of hybrid or unknown origin and are kept in zoos, farms, 
breeding facilities, circuses, and private homes. Scientists have long 
debated the role that captive tigers might play in conservation efforts.

To address the issue in the new study, the researchers developed a 
strategy for assessing the subspecies affiliation of tigers on the basis 
of diagnostic genetic markers obtained from 134 "voucher" tigers. They 
applied the method to samples from 105 captive tigers from 14 countries 
collected over 20 years. Of those, 49 individuals were found to 
represent one of five purebred subspecies, or VSA. The rest of the cats 
had mixed backgrounds.

They suspect that the proportion of purebreds observed in their study 
will be an overestimate for captive tigers worldwide. Nevertheless, they 
said, "If 14–23 percent of the over 15,000 existing captive tigers would 
prove to be VSA, the number of tigers with pure subspecies heritage 
available for conservation consideration would considerably increase.

" Also, an important fraction of captive tigers retain genetic diversity 
unreported, and perhaps absent, in the wild populations. A wide-ranging 
identification of captive VSA tigers to assess their potential for 
inclusion into comprehensive, integrated in situ and ex situ management 
plans could significantly increase population sizes and help maintain 
genetic variability and population viability of this iconoclastic species."

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The researchers include Shu-Jin Luo, National Cancer Institute, 
Frederick, MD, Department of Fisheries, Wildlife, and Conservation 
Biology, University of Minnesota, St. Paul, MI; Warren E. Johnson, 
National Cancer Institute, Frederick, MD; Janice Martenson, National 
Cancer Institute, Frederick, MD; Agostinho Antunes, National Cancer 
Institute, Frederick, MD, CIMAR, Universidade do Porto, Porto, Portugal; 
Paolo Martelli, Veterinary Department, Ocean Park, Aberdeen, Hong Kong; 
Olga Uphyrkina, Institute of Biology and Soil Sciences, Vladivostok, 
Russia; Kathy Traylor-Holzer, Conservation Breeding Specialist 
Group/SSC/IUCN, Apple Valley, MI; James L.D. Smith, Department of 
Fisheries, Wildlife, and Conservation Biology, University of Minnesota, 
St. Paul, MI; and Stephen J. O’Brien, National Cancer Institute, 
Frederick, MD.


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