SUDHAKAR, K (MAJOR)MURALIDHAR, MVENKATA SESHAIAH, Ch.JAYA MADHURI, BHUMIREDDY2020-07-102020-07-102019-11http://krishikosh.egranth.ac.in/handle/1/5810148957THESESThe Indian subcontinent is conferred with a rich livestock genetic diversity. Forty three sheep breeds are registered in India representing abundant genetic resources. Of these, Nellore sheep breed is harboured in Andhra Pradesh and is the only recognised breed of the state. Three phenotypically distinct varieties viz. Palla, Brown and Jodipi are present in the Nellore breed based on their coat colour. The present study is carried out to genetically characterize the Nellore Palla sheep and document the genetic divergence among the three varieties of the Nellore sheep breed. Thirty two unrelated individuals from the hometract of Palla, nine each of Brown and Jodipi were sampled for the molecular studies. Fluroscent microsatellite markers were used to genetically characterize Palla population. The analysis revealed a total of 201 alleles across the 26 loci studied. The mean observed and effective number of alleles per locus was 7.73 and 5.82 respectively. The overall observed and expected heterozygosity across 26 loci was 0.52 and 0.69 respectively. The mean FIS value in the sampled population was 0.24 with a range varying between -0.24 (MAF209) to 0.77 (INRA063). The mean PIC value and the Shannon’s index value across the 26 loci was 0.643 and 1.49 respectively. The study concluded a considerable amount of genetic diversity in the Nellore Palla population. The genetic divergence among the three varieties was analyzed using mitochondrial control region. DNA was isolated from the individuals of three varieties and 885 bp region of the mtDNA control region was amplified and sequenced. The analysis for polymorphism and divergence was done with DnaSP software and the results concluded a high polymorphism with in the genetic groups. The genetic differentiation estimates revealed no genetic differentiation among the three varieties of Nellore sheep breed. The phylogenetic analysis indicated that all the haplotypes of the three varieties of Nellore were clustering with lineage A except for one haplotype of Palla variety which was clustering with lineage B.ennullThesis