Comparative phylogeography of sympatric wild cats: Implications for biogeography and conservation in Asian biodiversity hotspots.

摘要

The dynamic geological history of Southeast Asia has resulted in a complex array of ecosystems including the contemporary climatic differences and floral transitions between the Indochinese and Sunda regions on the boundary of the Isthmus of Kra. This region is considered one of the most important biodiversity hotspots in the world and is home to 12 of the 37 recognized wild cat species most of which have been poorly studied. To examine the pattern of regional fauna diversification, this study compared intraspecific phylogeographic patterns in six sympatric Asian wild cat species (Asian leopard cat Prionailurus bengalensis vs. fishing cat P. viverrinus, Asian golden cat Pardofelis temmincki vs. marbled cat P. marmorata, and tiger Panthera tigris vs. leopard P. pardus). A total of 587 samples were examined using a multi-locus approach that covered the paternal (Y-chromosome DNA), maternal (mtDNA), and biparental (X-linked and autosomal loci) genetic lineages. With the exception of the leopard all species displayed phylogeographical breaks around the Isthmus of Kra. Concordant mtDNA and nuclear DNA genealogies suggest an ancient Indochinese/Sunda vicariant divergence (> 1 My) in both P. bengalensis and P. marmorata that coincided with rising sea level and climate change during the early to mid Pliocene and was likely reinforced by savannah-type habitat fragmentations during Pleistocene glacial maxima land bridges. A modern secondary contact zone of the two lineages in P. bengalensis exists on the Malay Peninsula. Divergence between the Indochinese and Malay lineages within P. tigris and P. temmincki were relatively recent and likely reflected genetic drift and reduced gene flow since 72,000 to 108,000 y ago in P. tigris, and 180,000 to 440,000 y ago in P. temmincki. The distinct phylogeographic structure in wild tigers also allows use of the diagnostic genetic markers to characterize the genetic background and to estimate the level of human-induced genetic admixture in 106 captive tigers. Overall the results suggest past vicariant divergences and highly structured phylogeographical patterns, and may be of conservation utility such as to assist in tracing the origins of illegally traded wildlife from the region, and to provide insights into the captive conservation breeding community.