Low diversity and high genetic divergence depicted the threat of genetic erosion in Calamus nambariensis and Calamus tenuis

Abstract

Calamus nambariensis Becc. and C. tenuis Roxb. are the rattan species of high economic significance in northeast (NE) India whose natural habitats were dramatically reduced. In the present study, natural populations of both the species collected from two north-eastern states, namely Mizoram and Tripura, were investigated for genetic diversity and differentiation using inter simple sequence repeat (ISSR) markers. As depicted by the calculated diversity indices, both the species have demonstrated lower genetic diversity at population level but relatively higher diversity was recorded at species level. Genetic divergence or genetic differentiation among sampled populations was recorded as high in C. nambariensis and very high in C. tenuis. Genetic clustering of sampled individuals was observed in accordance to their spatial distribution, which indicates the importance of geographical attributes in distribution of genetic diversity in natural populations of rattans. Combined analysis of four Calamus species has demonstrated that C. flagellum and C. nambariensis were most closely related and share a single gene pool during speciation. High to very high genetic divergence recorded here indicated the severe threat of genetic erosion that could be attributed to the degree of disturbances confronted by populations. This is the first study that dealt with population genetic analysis in both species, and data generated herein would be of immense importance for their conservation and management.