Molecular Genetic Characterization of Two Insular Asian Cat Species, Bornean Bay Cat and Iriomote Cat

Abstract

Molecular genetic data were used to characterize the genetic distinctiveness of Borncan bay cat (Pardofelis badia) and Iriomote cat (Prionailurus bengalensis iriomotensis), small cat species restricted to separate Asian islands. Sequence variation in two mitochondrial genes, NADH dehydrogenase subunit 5 (NADH-5) and ATPase-8 (ATP-8) was used to examine the phylogenetic relationship between a recently discovered Bornean bay cat specimen and the original type specimen (collected in 1855) relative to other Southeast Asian felids. DNA and amino acid sequence analyses affirmed that both bay cat specimens derived from the same phylogenetic lineage and that Bornean bay cat shared a monophyletic common ancestor with Asian golden cat (Profelis temmincki) estimated at 4.9-5.3 million years ago, well before the geological separation of Borneo from mainland Asia which occurred in the late Pleistocene, estimated as 10,000-20,000 years ago. The phylogenetic distinctiveness of the Iriomote cat (Prionailurus iriomotensis or P. bengalensis iriomotensis, n=5) from two leopard cat subspecies (P. b. euptilurus, n=5 and P. b. bengalensis, n=13) was examined based upon the DNA sequence variation of four mitochondrial genes, NADH-5, ATP-8, 16S rRNA, and Cytochrome b and based upon allele variation at 18 nuclear microsatellite loci. The available sample of Iriomote cats displayed a remarkable reduction in overall genetic diversity from diversity in both mtDNA and microsatellite variation compared to other felids. Nonetheless, the Iriomote cat genes clearly aligned them with, but distinct from, other subspecies of leopard cat (P. b. euptilurus and P. b. bengalensis) affirming their taxonomic classification as P. b. iriomotensis, subspecies. The contrasting patterns of the genetic variation of Bornean bay cat and Iriomote cat likely reflect different natural histories for these two island cat taxa.