Raed M. Al-Atiyat

Microsatellite-Based Genetic Structure and Diversity of Local Arabian Sheep Breeds

The genetic diversity of the sheep breeds in the Arab countries might be considered to be a mirror of the ecology of the region. In this study, the genetic structure and diversity of sheep breeds from Saudi Arabia (Harri, Najdi, Naemi, Arb, and Rufidi) and Awassi sheep from Jordan as an out-group were investigated using 19 microsatellites. All the breeds had high intra-population genetic diversity expressed as allelic number (7.33) and richness (2.9) and, expected heterozygosity (0.77). Structure analysis revealed three main gene pools underlying the ancestral genetic diversity of the study populations. The first pool had Harri, Najdi, and Rufidi breeds; the second had Naemi and Awassi breeds, and the third had the Arb breed which was significantly differentiated from the other breeds. Factorial correspondence analysis lent further support to the presence of the three gene pools. Although the outgroup Awassi sheep was more clearly differentiated, it still genetically close to Naemi sheep. The differentiation of the Arb breed could have been resulted from geographic and reproductive isolation. On the other hand, the genetic structure of the other two gene pools could be the result of the past and recent gene flow between individuals reared in the region known to be the center for animal husbandry and trading until the current time.

Genetic origin of goat populations in Oman revealed by mitochondrial DNA analysis

The Sultanate of Oman has a complex mosaic of livestock species and production systems, but the genetic diversity, demographic history or origins of these Omani animals has not been expensively studied. Goats might constitute one of the most abundant and important domestic livestock species since the Neolithic transition. Here, we examined the genetic diversity, origin, population structure and demographic history of Omani goats. Specifically, we analyzed a 525-bp fragment of the first hypervariable region of the mitochondrial DNA (mtDNA) control region from 69 Omani individuals and compared this fragment with 17 mtDNA sequences from Somalia and Yemen as well as 18 wild goat species and 1,198 previously published goat sequences from neighboring countries. The studied goat breeds show substantial diversity. The haplotype and nucleotide diversities of Omani goats were found equal to 0.983 ± 0.006 and 0.0284 ± 0.014, respectively. The phylogenetic analyses allowed us to classify Omani goats into three mtDNA haplogroups (A, B and G): haplogroup A was found to be predominant and widely distributed and accounted for 80% of all samples, and haplogroups B and G exhibited low frequencies. Phylogenetic comparisons with wild goats revealed that five of the native Omani goat populations originate from Capra aegagrus. Furthermore, most comparisons of pairwise population FST values within and between these five Omani goat breeds as well as between Omani goats and nine populations from nearby countries were not significant. These results suggest strong gene flow among goat populations caused by the extensive transport of goats and the frequent movements of human populations in ancient Arabia. The findings improve our understanding of the migration routes of modern goats from their region of domestication into southeastern Arabia and thereby shed light on human migratory and commercial networks during historical times.