Genetic differentiation of Indian dromedary and Bactrian camel populations based on mitochondrial ATP8 and ATP6 genes

Abstract

Camelids are acknowledged worldwide to endure hostile conditions prevalent in the hot as well cold deserts across the globe. Adaptations to climatic extremes have been associated with mitochondrial protein variants such as ATP8 and ATP6 in different species. The camel genetic resources of India are represented by 9 breeds of dromedary camels which inhabit hot arid and semi-arid zones of the country and a small population of Bactrian camels found in the cold desert of Ladakh. In this study, within and between breed genetic diversity in Indian dromedaries and their divergence from Bactrian camels was investigated based on ATP8/6 genes. Sequence analysis of a mitochondrial DNA fragment encompassing ATP8 and ATP6 genes identified 15 haplotypes in the dromedaries of India and 3 haplotypes in Bactrian camels. The values of haplotype diversity and nucleotide diversity were 0.647 and 0.00187 in the former and 0.679 and 0.00098, respectively in the latter. AMOVA analysis revealed 97.81% variance between the two species. Median-Joining network delineated three distinct mitochondrial haplogroups for Camelus dromedarius, Camelus ferus and Camelus bactrianus. Clear demarcation of the old world (Dromedary and Bactrian camels) and new world camelids (Alpaca, llama, guanaco and vicugna) was evident through the phylogenetic analysis.