Genomic Uniqueness of Local Sheep Breeds From Morocco.

Abdessamad Ouhrouch,Simon Boitard,François Pompanon,Frédéric Boyer,Badr Benjelloun,Bertrand Servin,Abdelmajid Haddioui,Anne Da Silva

doi:10.3389/fgene.2021.723599

Abstract

Sheep farming is a major source of meat in Morocco and plays a key role in the country’s agriculture. This study aims at characterizing the whole-genome diversity and demographic history of the main Moroccan sheep breeds, as well as to identify selection signatures within and between breeds. Whole genome data from 87 individuals representing the five predominant local breeds were used to estimate their level of neutral genetic diversity and to infer the variation of their effective population size over time. In addition, we used two methods to detect selection signatures: either for detecting selective sweeps within each breed separately or by detecting differentially selected regions by contrasting different breeds. We identified hundreds of genomic regions putatively under selection, which related to several biological terms involved in local adaptation or the expression of zootechnical performances such as Growth, UV protection, Cell maturation or Feeding behavior. The results of this study revealed selection signatures in genes that have an important role in traits of interest and increased our understanding of how genetic diversity is distributed in these local breeds. Thus, Moroccan local sheep breeds exhibit both a high genetic diversity and a large set of adaptive variations, and therefore, represent a valuable genetic resource for the conservation of sheep in the context of climate change.

Highlights

Sheep were among the first domesticated animals about 11,000 years B.P (Vigne, 2011; Demirci et al, 2013)
3.3.3 Overall Selection Signatures When combining both approaches, from a total of 31,721,507 analyzed SNPs, we identified as putatively under selection 46,799 variants associated with 155 genes in Sardi, 37,511 SNPs associated with 138 genes in Timahdite, 59,351 variants associated with 206 genes in Dman, 56,995 associated with 186 genes in the Beni Guil breed and 53,990 variants associated with 189 genes in Ouled Jellal
The heterozygosity measured in Moroccan breeds was generally moderate and globally lower than the values reported for Iranian sheep breeds (Eydivandi et al, 2021) and Welsh breeds (Beynon et al (2015)

Summary

Introduction

Sheep were among the first domesticated animals about 11,000 years B.P (Vigne, 2011; Demirci et al, 2013). They are one of the main sources of meat and milk around the world (Ritchie and Roser, 2017). The world production increase of sheep products was about 13.7% for meat and about 9.9% for milk between 2009 and 2019 (FAOSTAT, 2020). In order to achieve the United Nations SDG#2 (Sustainable Development Goals), the target #2.5 is directly concerned by maintaining genetic diversity in domestic species, and two associated indicators are related to the proportion of endangered breeds (#2.5.1 & #2.5.2).

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Discussion

Conclusion