Whole genome analysis of infectious bovine keratoconjunctivitis in Angus cattle using Bayesian threshold models

Kadir Kizilkaya,Richard G Tait,James M Reecy,Dorian J Garrick,Rohan L Fernando

doi:10.1186/1753-6561-5-s4-s22

Kadir Kizilkaya, Richard G Tait + Show 3 more

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https://doi.org/10.1186/1753-6561-5-s4-s22

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Journal: BMC Proceedings	Publication Date: Jun 3, 2011
Citations: 30	License type: cc-by

Affiliation: Iowa State University, Massey University

Abstract

Infectious bovine keratoconjunctivitis (IBK), also known as pinkeye, is characterized by damage to the cornea and is an economically important, lowly heritable, categorical disease trait in beef cattle. Scores of eye damage were collected at weaning on 858 Angus cattle. SNP genotypes for each animal were obtained from BovineSNP50 Infinium-beadchips. Simultaneous associations of all SNP with IBK phenotype were determined using Bayes-C that treats SNP effects as random with equal variance for an assumed fraction (π=0.999) of SNP having no effect on IBK scores. Bayes-C threshold models were used to estimate SNP effects by classifying IBK into two, three or nine ordered categories. Magnitudes of genetic variances estimated in localized regions across the genome indicated that SNP within the most informative regions accounted for much of the genetic variance of IBK and pointed out some degree of association to IBK. There are many candidate genes in these regions which could include a gene or group of genes associated with bacterial disease in cattle.

Highlights

Infectious Bovine Keratoconjunctivitis (IBK), commonly known as pinkeye, is a contagious bacterial disease caused in beef cattle by Moraxella bovis
The regions on chromosomes 2 (4000, relative single-nucleotide polymorphism (SNP) position), 13 (30900) and 23 (48300) were found to be common across threshold model analyses and to have the highest genetic variances in the whole genome analysis of Infectious bovine keratoconjunctivitis (IBK) scores for two, three or nine categories. Thereby, these regions could be indicative of QTL locations which are associated with IBK
Whole genome analysis of IBK using a marker-based threshold model identified genomic regions that were associated with IBK

Summary

Introduction

Infectious Bovine Keratoconjunctivitis (IBK), commonly known as pinkeye, is a contagious bacterial disease caused in beef cattle by Moraxella bovis. IBK is characterized by excessive tearing, inflammation of the conjunctiva, and ulceration of the cornea. Perforation of the cornea may occur which leads to permanent blindness. IBK is considered the most important ocular disease in cattle, due to the decreased performance of infected individuals and its subsequent economic effects. IBK is an economically important, lowly heritable (0.10 - 0.25), categorical disease trait. Breed differences in susceptibility of IBK have been established. In a number of studies, Hereford, Jersey and Holstein breeds appear to be more susceptible to infection than Bos Indicus breeds [1,2]. Additive genetic effects within breed are known to influence resistance to pinkeye [2].

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