Short tandem repeat (STR) based genetic diversity and relationship of domestic sheep breeds with primitive wild Punjab Urial sheep (Ovis vignei punjabiensis)

In this study, short tandem repeat (STR) genotypes of 466 sheep from eleven domestic breeds located in Asia, Africa, Europe and Latin America were compared with wild Asian Urial sheep and captive Mouflon type sheep to assess genetic diversity and relationship among them. Analysis of sheep breeds at 19 short tandem repeat (STR) loci revealed higher diversity in wild Punjab Urial sheep and domestic sheep from West Asia followed by Europe and Latin America as compared to South Asia, consistent with the history of sheep domestication. The average inter-individual allele sharing distance within breed was found to be lowest in South Asian sheep as compared to West Asian, European and Latin American sheep populations. The estimated global FST revealed 15.9% of total variation attributable to between breed differences. Investigation of genetic relationship by phylogeny revealed four distinct clusters; the first cluster formed by four South Asian sheep breeds, the second cluster formed by Iraqi and Bulgarian sheep breeds; the third cluster formed by Iranian, Austrian, Burkina Faso and Peruvian sheep breeds and the fourth cluster formed by Punjab Urial and captive mouflon type sheep. Principal components analysis revealed individuals from Punjab Urial sheep population being distributed close to the cluster of West Asian and East European sheep (Hamdani-Karakachanska-West Palminska) while being distinct from the cluster of four Indian breeds. Analysis of molecular variance (AMOVA) was performed to assess the distribution of STR variation as a function of both breed membership and geographic origin, the results of which revealed the structure based on phylogeny to be evidently stronger than the structure based on geographic origin. Bayesian clustering of individuals without prior population information revealed the most appropriate K with nine genetic clusters. In conclusion, the present study showed the Punjab Urial sheep being genetically closer to West Asian and East European sheep breeds as compared to South Asian sheep breeds. The microsatellite based nuclear DNA variations, thus confirmed the wild Punjab Urial sheep did not share any recent common ancestry with Asian domestic sheep, as reported earlier based on mitochondrial sequence variations.