Abstract
The Caspian tiger (Panthera tigris virgata) flourished in Central Asian riverine forest systems in a range disjunct from that of other tigers, but was driven to extinction in 1970 prior to a modern molecular evaluation. For over a century naturalists puzzled over the taxonomic validity, placement, and biogeographic origin of this enigmatic animal. Using ancient-DNA (aDNA) methodology, we generated composite mtDNA haplotypes from twenty wild Caspian tigers from throughout their historic range sampled from museum collections. We found that Caspian tigers carry a major mtDNA haplotype differing by only a single nucleotide from the monomorphic haplotype found across all contemporary Amur tigers (P. t. altaica). Phylogeographic analysis with extant tiger subspecies suggests that less than 10,000 years ago the Caspian/Amur tiger ancestor colonized Central Asia via the Gansu Corridor (Silk Road) from eastern China then subsequently traversed Siberia eastward to establish the Amur tiger in the Russian Far East. The conservation implications of these findings are far reaching, as the observed genetic depletion characteristic of modern Amur tigers likely reflects these founder migrations and therefore predates human influence. Also, due to their evolutionary propinquity, living Amur tigers offer an appropriate genetic source should reintroductions to the former range of the Caspian tiger be implemented.
Highlights
Tigers as a species historically ranged across Eurasia from the Sunda Islands, west through the Indian subcontinent to the Indus river and north along the Pacific seaboard to 60u NL and a wide swath of central Asia from the Russian Far East to eastern Turkey [1,2]
The amount of mtDNA variability observed in P. t. virgata (4 haplotypes/20 individuals), like P. t. altaica (1 haplotype/32 individuals), is low relative to other tiger subspecies P.t. tigris, (8 haplotypes/19 individuals); P. t. sumatrae, (10 haplotypes/31 individuals); P. t. jacksoni, (5 haplotypes/28 individuals); P. t. corbetti (5 haplotypes/33 individuals) [11,12,13] (Figure 2)
If colonization had occurred via the Indian subcontinent to the south a close molecular affinity would exist between Caspian tigers, P. t. virgata, and Bengal tigers, P. t. tigris, an affinity not supported by this data
Summary
Tigers as a species historically ranged across Eurasia from the Sunda Islands, west through the Indian subcontinent to the Indus river and north along the Pacific seaboard to 60u NL and a wide swath of central Asia from the Russian Far East to eastern Turkey [1,2]. This wide distribution was primarily influenced by environmental changes associated with Pleistocene glaciation events [3]. The Caspian tiger became extinct in February of 1970 when the last survivor was shot in Hakkari province, Turkey [1,7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
