Genetic Diversity and Population Structure Analyses of Threatened Amblyceps mangois from Sub-Himalayan West Bengal, India Through Rapd and ISSR Fingerprinting

摘要

Amblyceps mangois or the “Indian torrent catfish” is a tropical, freshwater, hill-stream species that has ornamental-commercial value and has been included within the “Endangered” category in the list of threatened freshwater fishes of India. A total fourteen populations from the Terai and Dooars region of northern West Bengal, India were analyzed to study the genetic architecture of this species with the help of RAPD and ISSR markers. The observed number of alleles (S), Nei’s gene diversity (H) and Shannon’s information index (H´ or I) showed the highest values in the Teesta river system and the lowest values in the Mahananda river system. The UPGMA-based dendrogram and PCoA, based on RAPD and ISSR fingerprints, showed that the Mahananda and the Teesta river populations formed a group distinct from the remaining Jaldhaka river population. We further considered the fourteen riverine populations into nine groups according to the continuity of the water flow for SHE analysis. It was found that the three components, i.e. the pattern of diversity (H´), richness (S) and evenness (E), have varied and fluctuated across all fourteen populations from higher to lower altitude as the river flows downstream. AMOVA, PhiPT and genetic hierarchical analyses showed that a distinct hierarchical structure is present in Amblyceps populations in the study region. Low levels of genetic diversity/variation and genetic hierarchical structure with high genetic divergence were found in the present study as an indicator of the recent picture of threatened status of this species. This study is the initial attempt to characterize and evaluate the genetic architecture of the species from this region and there is a scope to manage the evolutionary significant units (ESU) for conservation purpose.