Genomic-wide association study for gastrointestinal parasites resistance in Santa Inês sheep breed using SNPs and CNVs

Abstract

Sheep are animals of enormous socioeconomic importance throughout the world. However, losses caused by gastrointestinal parasites and costs due to excessive use of anthelmintic are a problem that hampers sheep production in many regions of the world. The Santa Inês breed, showed greater resistance to gastrointestinal nematode infections. Thus, the objective of this study was to perform the study of genomic association in characteristics associated with resistance to gastrointestinal parasites in Santa Ines sheep breeds adapted to the tropical climate. Evaluations of the phenotypes in 700 naturally infected animals of the Santa Inês breed will be performed to verify the resistance to gastrointestinal parasites. The phenotypes studied will be: anemia grade assessed by the famacha graph, egg count per gram of transformed stool (EPGlog), hematocrit (HCT), white blood cell count (WBC), red blood cells (RBC), hemoglobin (HGB) and platelets (PLT). A total of 576 animals genotyped by 12,785 biallelic SNP markers through the Ovine SNP12k BeadChip (Illumina, Inc.). Data quality control will be performed. The components of the variance will be estimated through a single step model (ssGBLUP), under Bayesian inference. For the detection of CNVs, the PennCNV algorithm will be used and after the identification of the CNVs, the CNV regions (CNVRs) will be generated using the CNVRuler program. Quantitative trait loci (QTL) will be possible. The "Map Viewer" tool of the ovine genome (Ovis aries) will be used to identify genes. The classification of the genes according to their biological function, identification of metabolic pathways and enrichment of genes will be performed by the DAVID v6.8 tool and GeneCards.