A preliminary investigation on the population genetic structure of Etroplus canarensis day, 1877 of the western Ghats, India

Abstract

The ‘Canara pearl spot’, Etroplus canarensis Day, 1877 is an endangered and endemic freshwater fish with a restricted distribution in the Western Ghats of India. In spite of the importance as an ornamental fish, no genetic and conservation studies are available for the species. In this work, mitochondrial 16S ribosomal gene sequences were used to infer the population genetic structure of three geographical populations. It is deduced from the study that all three populations in the study can be considered as a single population with a bottleneck or founder effect. Low haplotype and nucleotide diversity were observed among populations. These were supported by AMOVA analysis that showed the total variations are within the populations. Furthermore, data on the pairwise genetic distance (FST) and the rate of migration among populations (Nm) showed very weak genetic differentiation with low gene flow between populations. The phylogenetic tree with clustering of all haplotypes from three populations further supports the upshot of a single population. Meanwhile, the neutrality test results (Tajima’s D, Fu’s Fs, D*, and F*) provided evidence for the population bottleneck. Haplotype network analysis revealed a recent population expansion and the presence of a founder haplotype. Consolidated results of haplotype network and neutrality tests propose the scenario of recovery of the population from earlier bottleneck succeeded by very recent population expansion. The results provided in the study may serve as baseline data for future investigations.