Haplotype and Genetic Diversity of mtDNA in Indigen ous Iranian Sheep and an Insight into the History of Sh eep Domestication

Abstract

The archaeological evidence suggests that Iran has been one of the first origins of sheep domestication in the world. This study aims to inve stigate the genetic diversity of indigenous Iranian sheep breeds using mitochondrial DNA (mtDNA) and to explore the evolutionary history of sheep domestication in Iran . Single Nucleotide Polymorphism (SNP) markers in the control region of mtDNA were u sed to genotype the unrelated sheep samples of Zel and Lori-Bakhtiari breeds which were collected from or near the center of the sheep domestication, using the Sequenom MassARR AY platform. Phylogenetic analysis of the mitochondrial SNPs classified all a nimals into either of two haplogroups A and B. The population differentiation (F ST ) and gene flow (N m ) statistics were 0.054 and 4.715 respectively, indicating a low mitochondrial genetic differentiation and high gene flow between two sheep breeds. The Analysis of Vari ation (AMOVA) showed that around 97% of the total genetic diversity is distributed w ithin the two breeds. Further analysis using SNP haplotyping identified nine different hap lotypes within the animals; eight haplotypes were present in the Zel, while only four were seen in the Lori-Bakhtiari breed. Two haplotypes, designated H 1 and H 3 , were present at higher frequencies in both breeds . Haplotyes H 5 , H 6 , H 7 , H 8 and H 9 were found as population-specific in the Zel, and haplotype H 2 only occurred in Lori-Bakhtiari breed. The existenc e of two common Haplotypes (H 1 and H 3 ) in the animals suggest that the two Iranian breed s from strikingly different geographical regions, may share a common ancestry, and these haplotypes could be the origin haplotypes while the population speci fic haplotypes developed later. Keywords: Genetic diversity, Haplogroups, Mitochondrial genom e, Phylogenetic study, Sheep evolution.