Genetic identification of wild Asian water buffalo in Nepal

Abstract

The wild water buffalo is highly endangered, with the few remaining populations already affected or likely to be increasingly affected by hybridization with domestic buffalo. The work described here was done to evaluate a genetic method to discriminate wild from mixed ancestry (hybrid) and domestic animals, and to identify with high probability those most likely to be purebred wild. Samples from 45 animals (phenotypically classified into three groups -ten wild, 28 domestic and seven hybrid) were genotyped for ten microsatellite loci. Although genetic distances among the three groups were small, an assignment test identified two of the 'wild' and seven of the 'domestic' as hybrids. However, sample sizes also are small, indicating the need for a conservative approach in the first instance in using these results. As more animals are genotyped, assignments will become more accurate, and a translocation programme to establish a second Nepalese wild population in a protected area could be undertaken.

Assignment methods: matching biological questions with appropriate techniques

“…The program STRUCTURE [15,17] assigns gene copies probabilistically to potential sources; individuals with genes assigned with non-trivial probabilities to two sources are potential hybrids. This method has been used to study hybrids in the wild for several species [45,46]; for example, Randi and Lucchini [45] used it to confirm the introgression of domestic dog genes into the Italian wolf. Although ordination and tree-based methods could not detect introgression, STRUCTURE clearly identified as a hybrid one wolf that was also a suspected hybrid based on morphology (unusually dark fur).…”

Molecular detection of hybridization between sympatric kangaroo species in south-eastern Australia

“…Q-values of allopatric and simulated representative M. fuliginosus and M. giganteus ranged between 0.92 and 0.98 to their respective species clusters in STRUCTURE 2.1 (Pritchard et al, 2000), whereas simulated F1 hybrids ranged between 0.3 and 0.7 (see the Results section). On the basis of these ranges and those of similar studies (Flamand et al, 2003;Vaha and Primmer, 2005;Lancaster et al, 2006), a threshold of 0.9 was used to distinguish between pure and hybrid individuals in STRUCTURE (that is, o0.9 indicates putative hybrid; separation into hybrid categories was not feasible; see the Results section). In NEWHYBRIDS (Anderson and Thompson, 2002), assignment probabilities of allopatric and simulated representative M. fuliginosus and M. giganteus to their respective species categories ranged between 0.77 and 1.00, whereas the assignment of simulated F1 hybrids to the F1 category ranged between 0.35 and 1.00.…”

Status of key faunal species in Koshi Tappu Wildlife Reserve after Koshi flood disaster 2008

“…All these data show a population growth of wild water buffalo in KTWR is satisfactory. But 2 of the predefined as wild buffalo and 7 of the predefined as domestic buffalo showed evidence of mixed ancestry in the genetic analysis of wild water buffalo examined (Flamand et al, 2003). Habitat of wild water buffalo was also studied in our survey.…”

“…During high water periods, there is a chance of dolphins to move downstream through the Koshi Barrage but the high current might have prevented them from swimming upstream through the barrage. The effects of subdividing a single population into non-interacting insular units increase their vulnerability to environmental, demographic and genetic (Haque et al, 1998 The wild water buffalo in KTWR is highly endangered; with the few remaining populations already affected or likely to be affected by hybridization with domestic buffalo (Flamand et al, 2003). Population estimation of wild water buffalo in KTWR was initiated by Dahmer (1978) with a count of 63 individuals in 1976.…”