Genome-wide association studies for resumption of postpartum ovarian cyclicity trait in seasonal anestrus in Spanish Merino sheep breed

The effects of the climate change are expected to affect direct and indirect on livestock physiology and health by increasing exposure to environmental stressors like heat stress or water deprivation, mainly in arid and semi-arid regions, especially in the south edge of the Mediterranean basin. The aim of this study is to identify candidate genes or genomic regions associated with ovine stress biomarkers through genome-wide association analysis. Two-hundred and one ewes from the Rasa Aragonesa breed were challenged with total water restriction for 5 days. Temperature and percentage of humidity was also measured, as well as intake, live weight, and body condition score daily during the 5 days restriction. Blood samples were collected just prior to the challenge (0d) and at the end of the challenge (5d), obtaining haematological (white, red blood cells and platelet traits) and metabolite (total protein, glucose, non-esterified fatty acids (NEFA), cortisol, DHEA and DHEAS concentration phenotypes) measurements. Wool samples were also collected at day 0 and 4 weeks later (28d), and cortisol, DHEA and DHEAS were also measured. In addition to these measurable traits for each blood/wool sample, variation of traits between blood or wool samples collected at different time points were also calculated for each animal. Genotyping was performed using the Ovine680kBeadChip. AIREMLF90 package from the BLUPF90 family programs was used to estimate variance components for each trait using the average information-restricted maximum likelihood (AI-REML). GCTA software (Yang et al., 2011) was used for GWAS analysis. Mixed model statistical analysis indicated that all haematological and metabolite levels showed consistent changes throughout water restriction period with the exception of plasma cortisol and MCH. It is outstanding that the neutrophils to lymphocyte ratio in close relationship with stress hormones was also altered. We found 56 SNPs associated with different biomarkers at genome-wide significant level (p_Bonferroni < 0.05), which were annotated against the ovine reference genome (Oar_rambouillet_v1.0). Some candidate genes located in within a 500 kb-long interval centered on the significant SNPs were CDK14, CD88, GALNT5, MEIS1 and SEC16B for neutrophil traits, or PLA2G4F, PLA2G4D, and PRKCB for DHEA wool traits. We performed GO and KEGG pathway enrichment analyses using DAVID through the Functional Annotation Cluster (FAC) tool, finding one cluster of enrichment related to the hypothalamic-pituitary-adrenal axis in wool DHEA phenotype.

Bibliographic Details

Main Authors:	Pérez-Redondo, Sara, Calvete, Carlos, Joy, M., Lobón, Sandra, Serrano Noreña, Magdalena, Domínguez, Andrés, Calvo, Jorge Hugo
Other Authors:	Department of Agriculture (US)
Format:	comunicación de congreso biblioteca
Language:	English
Published:	International Society for Animal Genetics 2023-07-03
Subjects:	Sheep, Water stress, Metabolites, GWAS, SNP,
Online Access:	http://hdl.handle.net/10261/352241
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