A comparative study of the use of tiger-specific and heterologous microsatellite markers for population genetic studies of the Bengal tiger (<i>Panthera tigris tigris</i>)

Abstract

Comparison of genetic diversity indices of heterologous and species-specific microsatellite loci within a species may provide a panel of appropriate markers for genetic studies, but few studies have carried out such comparisons. We examined and compared the genetic characteristics of tiger-specific and heterologous loci in eight captive Bengal tigers. The mean polymorphic information content (PIC) value of the tiger-specific microsatellite loci (n = 15) was 0.447, and the number of alleles was from 2 to 4 per locus. In comparison, the heterologous microsatellite loci (n = 15) had a mean PIC value of 0.539, and the number of alleles per locus was three to five. Our findings indicate that the heterologous markers have a higher frequency (n = 11) of polymorphic microsatellite loci and number of alleles per locus compared with tiger-specific loci. We pooled the highly polymorphic (PIC > 0.5) tiger-specific loci (n = 5) and heterologous microsatellite loci (n = 11) except one and noted a higher mean observed heterozygosity and PIC values of 0.668 and 0.575, respectively, compared with the heterologous and tiger-specific loci taken alone. Using a locus selection criterion of PIC > 0.5, we recommend a combined panel of 16 highly polymorphic loci for genetic studies of the wild population of the Bengal tigers and suggest that either a combination of tiger-specific and heterologous microsatellite primers or heterologous primers be used in genetic studies related to the ecology, biology, socio-biology and behavior of Bengal tigers as >13 loci are needed in such studies.

Keywords: Bengal tiger, highly polymorphic, tiger-specific, heterologous, microsatellite loci.