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Elbeltagy A.R.,Egyptian Animal Production Research Institute | Aboul-Naga A.M.,Egyptian Animal Production Research Institute | Hassen H.,Small Ruminant Genetics and Genomics Group | Rischkowsky B.,Small Ruminant Genetics and Genomics Group | Mwacharo J.M.,Small Ruminant Genetics and Genomics Group
Small Ruminant Research | Year: 2015

Human exchange networks are instrumental in influencing gene flow among domesticates. Here, we investigated levels of within- and between-population genetic diversity in 289 animals from six indigenous sheep populations in Egypt (Barki, Farafra, Ossimi, Rahmani, Saidi, Souhagi) and 119 individuals of Awassi breed from Egypt, Turkey and Syria using 13 autosomal microsatellites. Although our analysis revealed genetic differentiation between Souhagi and other Egyptian populations, and between the Awassi from Egypt and the ones from Syria and Turkey, most likely due to reproductive isolation, Bayesian analysis identified two gene pools underlying the ancestral genetic diversity while multivariate analysis identified nine genetic clusters which could be subdivided into four broad genetic groups. Further analysis revealed that this genetic structure was the result of the exchange of genetic stocks along the Nile River valley and the Mediterranean Sea coast, but, minimal gene flow between flocks found in the Northern, Central and Southern Egypt across the Western desert. Our results support the fact that human interaction networks have shaped the genetic architecture of domestic animals while harsh environments such as deserts tend to limit human interactions and hence gene flow among domesticates. © 2015 Elsevier B.V.. Source

Kim E.-S.,Iowa State University | Elbeltagy A.R.,Egyptian Animal Production Research Institute | Aboul-Naga A.M.,Egyptian Animal Production Research Institute | Rischkowsky B.,Small Ruminant Genetics and Genomics Group | And 3 more authors.
Heredity | Year: 2016

Goats and sheep are versatile domesticates that have been integrated into diverse environments and production systems. Natural and artificial selection have shaped the variation in the two species, but natural selection has played the major role among indigenous flocks. To investigate signals of natural selection, we analyzed genotype data generated using the caprine and ovine 50K SNP BeadChips from Barki goats and sheep that are indigenous to a hot arid environment in Egypt's Coastal Zone of the Western Desert. We identify several candidate regions under selection that spanned 119 genes. A majority of the genes were involved in multiple signaling and signal transduction pathways in a wide variety of cellular and biochemical processes. In particular, selection signatures spanning several genes that directly or indirectly influenced traits for adaptation to hot arid environments, such as thermo-tolerance (melanogenesis) (FGF2, GNAI3, PLCB1), body size and development (BMP2, BMP4, GJA3, GJB2), energy and digestive metabolism (MYH, TRHDE, ALDH1A3), and nervous and autoimmune response (GRIA1, IL2, IL7, IL21, IL1R1) were identified. We also identified eight common candidate genes under selection in the two species and a shared selection signature that spanned a conserved syntenic segment to bovine chromosome 12 on caprine and ovine chromosomes 12 and 10, respectively, providing, most likely, the evidence for selection in a common environment in two different but closely related species. Our study highlights the importance of indigenous livestock as model organisms for investigating selection sweeps and genome-wide association mapping. © 2016 Macmillan Publishers Limited. All rights reserved. Source

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