Genetic ancestry of the extinct Javan and Bali tigers.

The Bali (Panthera tigris balica) and Javan (P. t. sondaica) tigers are recognized as distinct tiger subspecies that went extinct in the 1940s and 1980s, respectively. Yet their genetic ancestry and taxonomic status remain controversial. Following ancient DNA procedures, we generated concatenated 1750bp mtDNA sequences from 23 museum samples including 11 voucher specimens from Java and Bali and compared these to diagnostic mtDNA sequences from 122 specimens of living tiger subspecies and the extinct Caspian tiger. The results revealed a close genetic affinity of the 3 groups from the Sunda Islands (Bali, Javan, and Sumatran tigers P. t. sumatrae). Bali and Javan mtDNA haplotypes differ from Sumatran haplotypes by 1-2 nucleotides, and the 3 island populations define a monophyletic assemblage distinctive and equidistant from other mainland subspecies. Despite this close phylogenetic relationship, no mtDNA haplotype was shared between Sumatran and Javan/Bali tigers, indicating little or no matrilineal gene flow among the islands after they were colonized. The close phylogenetic relationship among Sunda tiger subspecies suggests either recent colonization across the islands, or else a once continuous tiger population that had subsequently isolated into different island subspecies. This supports the hypothesis that the Sumatran tiger is the closest living relative to the extinct Javan and Bali tigers.