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Summer Research Fellowship Programme of India's Science Academies

Understanding the Genetic Diversity of Nyctibatrachus kempholeyensis of Central Western Ghats using Mitochondrial and Microsatellite Genetic markers

Kausalya Sakthivel

B.Tech Biotechnology, CPMB&B, Tamilnadu Agricultural University, Coimbatore 641003

Dr. G. Ravikanth

Fellow, Conservation Genetics Lab, Ashoka Trust for Research in Ecology and the Environment (ATREE), Royal Enclave, Srirampura, Jakkur, Bengaluru 560064.

ABSTRACT

Amphibians, ectothermic tetrapod vertebrates, across the globe are declining at an alarming rate (Stuart et al. 2004). Habitat destruction which includes fragmentation, degradation, modification and rapid urbanization are considered to be the key factors which impact amphibian decline. Amphibians are very sensitive to environmental changes. They are vulnerable because of their permeable skin, use of multiple habitat, dependence on water, complex life cycles, habitat isolation and specialisation, population structure, limited geographic range, small body size, ectothermic metabolism, limited dispersal ability, anti-predator behaviour and boom and bust population cycles (Wells 2010). Habitat fragmentation and other landscape changes reduce the gene flow which ultimately results in decreasing genetic diversity. A decrease in genetic diversity leads to reduced fitness, lack of adaptability to the changing environment and is thus associated with extinction risk. The maintenance of population genetic diversity is important for the conservation of amphibians. As a consequence, amphibian decline may have knock-out effects on other trophic levels and thereby threaten other species, ecosystem structure and function (Whiles et al. 2006).

The Indian subcontinent provides home to a wide variety of flora and fauna. Over 300 amphibian species are currently known to occur in the Western Ghats (Dinesh et al. 2013). The Western Ghat mountains are regarded as a biodiversity hotspot (Myers et al. 2000), where more than 92% of the known 225 amphibian species are endemic (Garg et al. 2017). The families Dicroglossidae, Rhacophoridae, and Nyctibatrachidae account for 50% of the total species richness in the Western Ghats (Aravind and Gururaja 2011). The high level of endemism in the Western Ghats is a result of the discontinuity in the mountain chain that restricts dispersal (Naniwadekar and Vasudevan 2007).

Nyctibatrachus, a genus of frogs which are endemic to the Western Ghats of India, is nocturnal in nature and is a less vagile species. There are about 36 species at present. A phylogeographic study showed that they are clade endemic and poor dispersers (Van boxclaer et al. 2012). Therefore, it is important to study their genetic variation. In this study, the genetic diversity of Nyctibatrachus kempholeyensis from multiple river basins was analysed using both mitochondrial and microsatellite markers. The knowledge gained from this study will provide an important insight into the population history of this species.

Keywords: Ectothermic tetrapod, Nyctibatrachus kempholeyensis, Habitat destruction, Endemic, Phylogeographic study, Microsatellite markers

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