Genetic Affinities and Adaptation of the South-West Coast Populations of India

Evolutionary event has not only altered the genetic structure of human populations but also associated with social and cultural transformation. South Asian populations were the result of migration and admixture of genetically and culturally diverse groups. Most of the genetic studies pointed to large-scale admixture events between Ancestral North Indian (ANI) and Ancestral South Indian (ASI) groups, also additional layers of recent admixture. In the present study, we have analyzed 213 individuals inhabited in South-west coast India with traditional warriors and feudal lord status and historically associated with migratory events from North/North West India and possible admixture with West Eurasian populations, whose genetic links are still missing. Analysis of autosomal Single Nucleotide Polymorphism (SNP) markers suggests that these groups possibly derived their ancestry from some groups of North West India having additional Middle Eastern genetic components. Higher distribution of West Eurasian mitochondrial haplogroups also points to female-mediated admixture. Estimation of Effective Migration Surface (EEMS) analysis indicates Central India and Godavari basin as a crucial transition zone for population migration from North and North West India to South-west coastal India. Selection screen using 3 distinct outlier-based approaches revealed genetic signatures related to Immunity and protection from Viral infections. Thus, our study suggests that the South-west coastal groups with traditional warriors and feudal lords' status are of a distinct lineage compared to Dravidian and Gangetic plain Indo-Europeans and are remnants of very early migrations from North West India following the Godavari basin to Karnataka and Kerala.

Stable sulphur isotope (δ34S) ratios in bird feathers from India indicate strong segregation between the Himalaya and Gangetic plain, and the rest of India

Although stable hydrogen (δ²H) and carbon (δ¹³C) isotopic compositions of bird feathers have been increasingly used to understand the migration of birds through assignment of individuals to established isoscapes, far less is known about the structure of feather isoscapes based on stable sulphur isotope (δ³⁴S) assays. While δ²H isoscapes have been used to investigate the migratory origins of the Globe Skimmer (Pantala flavescens) dragonfly in India, no isotope studies have been applied to avian migration patterns in that region. Here, based on museum collections, we report the feather δ³⁴S values of 13 avian species that included marine birds with expected ³⁴S enriched feathers, resident birds throughout India and a single migratory species, Bar-headed Goose (Anser indicus). Feathers from the marine birds were the most enriched (20.6 ± 1.2 ‰, n = 10; range = 4.4 ‰) in ³⁴S but terrestrial resident species also showed unexpectedly high δ³⁴S values (11.7 ± 4.8 ‰, n = 74; range = 19.9 ‰) throughout most of India but the Himalayan region and Gangetic plain typically showed δ³⁴S values less than 6.4 ‰. Our results show the utility of feather δ³⁴S studies to decipher avian and other animal migration between these two regions.

Climate change-induced salinity variation impacts on a stenoecious mangrove species in the Indian Sundarbans

The alterations in the salinity profile are an indirect, but potentially sensitive, indicator for detecting changes in precipitation, evaporation, river run-off, glacier retreat, and ice melt. These changes have a high impact on the growth of coastal plant species, such as mangroves. Here, we present estimates of the variability of salinity and the biomass of a stenoecious mangrove species (Heritiera fomes, commonly referred to as Sundari) in the aquatic subsystem of the lower Gangetic delta based on a dataset from 2004 to 2015. We highlight the impact of salinity alteration on the change in aboveground biomass of this endangered species that, due to different salinity profile in the western and central sectors of the lower Gangetic plain, shows an increase only in the former sector, where the salinity is dropping and low growth in the latter, where the salinity is increasing.