AUTHOR=Esmaeili-Fard Seyed Mehdi , Gholizadeh Mohsen , Hafezian Seyed Hasan , Abdollahi-Arpanahi Rostam 

TITLE=Genes and Pathways Affecting Sheep Productivity Traits: Genetic Parameters, Genome-Wide Association Mapping, and Pathway Enrichment Analysis

JOURNAL=Frontiers in Genetics

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2021.710613

DOI=10.3389/fgene.2021.710613

ISSN=1664-8021

ABSTRACT=<p>Ewe productivity is a composite and maternal trait that is considered the most important economic trait in sheep meat production. The objective of this study was the application of alternative genome-wide association study (GWAS) approaches followed by gene set enrichment analysis (GSEA) on the ewes’ genome to identify genes affecting pregnancy outcomes and lamb growth after parturition in Iranian Baluchi sheep. Three maternal composite traits at birth and weaning were considered. The traits were progeny birth weight, litter mean weight at birth, total litter weight at birth, progeny weaning weight, litter mean weight at weaning, and total litter weight at weaning. GWASs were performed on original phenotypes as well as on estimated breeding values. The significant SNPs associated with composite traits at birth were located within or near genes <italic>RDX</italic>, <italic>FDX1</italic>, <italic>ARHGAP20</italic>, <italic>ZC3H12C</italic>, <italic>THBS1</italic>, and <italic>EPG5</italic>. Identified genes and pathways have functions related to pregnancy, such as autophagy in the placenta, progesterone production by the placenta, placental formation, calcium ion transport, and maternal immune response. For composite traits at weaning, genes (<italic>NR2C1</italic>, <italic>VEZT</italic>, <italic>HSD17B4</italic>, <italic>RSU1</italic>, <italic>CUBN</italic>, <italic>VIM</italic>, <italic>PRLR</italic>, and <italic>FTH1</italic>) and pathways affecting feed intake and food conservation, development of mammary glands cytoskeleton structure, and production of milk components like fatty acids, proteins, and vitamin B-12, were identified. The results show that calcium ion transport during pregnancy and feeding lambs by milk after parturition can have the greatest impact on weight gain as compared to other effects of maternal origin.</p>