Subspecies Genetic Assignments of Worldwide Captive Tigers Increase Conservation Value of Captive Populations

Summary Tigers ( Panthera tigris ) are disappearing rapidly from the wild, from over 100,000 in the 1900s to as few as 3000 [1, 2]. Javan ( P.t. sondaica ), Bali ( P.t. balica ), and Caspian ( P.t. virgata ) subspecies are extinct, whereas the South China tiger ( P.t. amoyensis ) persists only in zoos [1, 3]. By contrast, captive tigers are flourishing, with 15,000–20,000 individuals worldwide, outnumbering their wild relatives five to seven times [4]. We assessed subspecies genetic ancestry of 105 captive tigers from 14 countries and regions by using Bayesian analysis and diagnostic genetic markers defined by a prior analysis of 134 voucher tigers of significant genetic distinctiveness [5]. We assigned 49 tigers to one of five subspecies (Bengal P.t. tigris , Sumatran P.t. sumatrae , Indochinese P.t. corbetti , Amur P.t. altaica , and Malayan P.t. jacksoni tigers) and determined 52 had admixed subspecies origins. The tested captive tigers retain appreciable genomic diversity unobserved in their wild counterparts, perhaps a consequence of large population size, century-long introduction of new founders, and managed-breeding strategies to retain genetic variability. Assessment of verified subspecies ancestry offers a powerful tool that, if applied to tigers of uncertain background, may considerably increase the number of purebred tigers suitable for conservation management.