Nicobari fowl constitute an endemic poultry germplasm of Andaman and Nicobar Islands, India. Genetic diversity, population structure and ancestry of Nicobari fowl were analysed with mitochondrial D-loop sequences. Analysis of complete D-loop sequences (1231–1232 bp) showed 46 polymorphic sites resulting in 26 haplotypes with overall haplotype diversity of 0.895 and nucleotide diversityof 0.0064. Analysis of molecular variance of spatial populations (sampling sites) of Nicobari fowl revealed that the estimated F_ST value as 0.229 among the populations. Tajima's D and Fu's F_S tests indicated nonsignificant deviation from neutrality and the multimodal pattern of mismatch distribution in demographic expansion suggested that Nicobari fowl populations are in equilibrium. The median-joining (MJ) network of D-loop sequences with reference haplogroup sequences identifies the presence of haplogroups A, B, E1, E2, F and I in Nicobari fowl. The major haplogroup in Nicobari fowl was E (60%), which is otherwise found mainly in the Indian subcontinent. Phylogenetic analysis of Nicobari fowl with junglefowl by maximum likelihood method showed Gallus gallus murghi and G. g. spadiceus as maternal progenitors. Grouping of Nicobari fowl with their primary ancestor, Indian red Junglefowl (G. g. murghi) and the presence of Indian subcontinent-specific haplogroups (E2 and I) support the independent domestication of chickens in India. This study will help to designbreeding strategy for conservation of Nicobari fowl in its island habitat.

The tick, Rhipicephalus microplus is considered as the most notorious ectoparasite of veterinary importance in tropical and sub-tropical regions of the world. The present study deals with the molecular characterization of R. microplus in different regions of Andaman and Nicobar Islands using sequence information of mitochondrial cytochrome C oxidase subunit I (COX1) and their phylogenetic relationship with other Indian R. microplus genotypes. DNA polymorphism study identified a total of eight haplotypes with haplotypediversity of 0.909 ± 0.065 and nucleotide diversity of 0.01911 ± 0.00493. Currently, R. microplus complex consists of five taxa; R. microplus clade A sensu Burger et al. (2014), R. microplus clade B sensu Burger et al. (2014), R. microplus clade C sensu Low et al. (2015), R. australis and R. annulatus. Phylogenetic analysis revealed the presence of two clades (clade A and clade C) of R. microplus in Andaman and Nicobar isolates; Nicobar isolates belonged to clade A whereas Andaman isolates belonged to clade C of R. microplus complex. All the other Indian sequences retrieved from GenBank belonged to clade C of R. microplus complex. Andaman isolates under clade C of R. microplus were phylogenetically distinct from Indian isolates, which indicates independent speciation under isolated island milieu. In Indian isolates, no host-specific or geographical location-specific sub-clustering was observed which indicates the species jumping potential of the R. microplus tick. Therefore, this study indicated the presence of two different genetic makeup of R. microplus complex in two areas of the Andaman and Nicobar archipelago separated by a natural geographical barrier. This indicates presence of two different founding populations of ticks, one in the south and north-middle Andaman and the other in Nicobar Island.