Abstract

Copy number variations (CNVs) are the largest source of genetic variation that has been identified in the equine genome so far. CNV-based GWAS could therefore facilitate detection of genetic variation for traits of interest. The aim of our study was to identify, characterize and associate CNVs in Friesian horses with insect bite hypersensitivity (IBH), a common equine allergy to insects that causes intense itch and seriously reduces welfare. After pre-processing of raw intensity signals from 670,796 SNPs for 138 cases and 131 controls, CNVs were identified using PennCNV and merged into CNV regions (CNVRs) using CNVRuler. A SNP-based GWAS performed beforehand (chi squared test with 1df) showed a clear association between the ELA region on ECA20 and IBH in Friesian horses. Regions identified on ECA9, 11 and 20 have rather consistently been associated with IBH across equine breeds investigated so far. Currently, the CNV analysis is at an early stage and different strategies to improve the SNP array overall signal quality are being tested. The preliminary CNV-based GWAS, which analysed gains and losses separately by logistic regression, indicated a loss in the ELA region significantly more frequent in affected horses. CNVRs significantly associated with IBH could point to genes involved in this complex polygenic disease. Our study will increase the knowledge on CNVs in horses and will highlight which genes and pathways are affected by CNVs. Moreover, it will facilitate in our attempt to improve selection against IBH.

Published in

Annual meeting of the European Association for Animal Production
2016, number: 22, pages: 286-286
Book title: Book of Abstracts of the 67th Annual Meeting of the European Federation of Animal Science
ISBN: 978-90-8686-284-9, eISBN: 978-90-8686-830-8
Publisher: Wageningen Academic Publishers

Authors' information