Dwarf chameleon fish or Badis badis, a lesser known ornamental freshwater fish, has recently been included in the Indian threatened category of fish list. There are insufficient studies with regard to the assessment of genetic background of this ichthyofauna, especially in the western sub-Himalayan region of West Bengal, India, popularly known as the Terai. The present study is the first attempt to investigate the present status of the genetic background of this species in the Mahananda and Balason rivers, major streams of this region. Twenty-one selective RAPD primers generated 53 and 60 polymorphic fragments in the Mahananda and Balason populations, respectively. The proportion of polymorphic loci, Nei's genetic diversity (H), and Shannon's index ( ) were 0.4416, 0.1654 ± 0.2023, and 0.2450 ± 0.2907, respectively, in Mahananda river population and were 0.5041, 0.1983 ± 0.2126, and 0.2901 ± 0.3037, respectively, in Balason river population. Inbreeding coefficient and degree of gene differentiation were also calculated. The H and were found to be 0.1601±0.1944 and 0.2363±0.2782, respectively, in overall Mahananda-Balason river system. Our study revealed considerable lack of genetic variation among the individuals of Badis badis. The genetic data obtained from the present study lend support to the view that there is a scope of stock improvement for this ichthyofauna.
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.
Badis badis is a threatened freshwater fish in the Indian scenario, and the population genetic architecture of this fish is largely unexplored in the eastern sub-Himalayan biodiversity hotspot of West Bengal, India, also known as the Terai and the Dooars. Total seventeen populations from three major river systems viz. Mahananda (Terai), Teesta and Jaldhaka (Dooars) have been studied through RAPD and ISSR fingerprinting. The polymorphism, genetic diversity and Shannon's Information index were calculated for each population. The highest values for Nei's genetic diversity (0.1436± 0.1963 and 0.1409 ±0.1954 after RAPD and ISSR analyses) and Shannon's information index (0.2150±0.2794 and 0.2109 ±0.2785 after RAPD and ISSR analyses) were found in Jaldhaka river system. The UPGMA dendrogram revealed that the Mahananda and Teesta populations form a single group and the Jaldhaka population forms a separate group. Comparing with other related studies the genetic diversity Badis badis was found to be low in the three main riverine systems of the Terai and Dooars region of West Bengal, although the Jaldhaka population showed a comparatively higher level of genetic diversity. Therefore, Jaldhaka population should be managed and, conserved to preserve the available gene pool of this threatened species in this region. Low levels of genetic diversity were found in the present study among the seventeen populations validating the recent assignment of its threatened status.
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