Genome-wide association study of infectious bovine keratoconjunctivitis in Angus cattle.

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

doi:10.1186/1471-2156-14-23

Kadir Kizilkaya, Richard G Tait + Show 3 more

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https://doi.org/10.1186/1471-2156-14-23

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Journal: BMC genetics	Publication Date: Mar 26, 2013
Citations: 56	License type: cc-by

Affiliation: Iowa State University, Massey University

Abstract

BackgroundInfectious Bovine Keratoconjunctivitis (IBK) in beef cattle, commonly known as pinkeye, is a bacterial disease caused by Moraxellabovis. IBK is characterized by excessive tearing and ulceration of the cornea. Perforation of the cornea may also occur in severe cases. IBK is considered the most important ocular disease in cattle production, due to the decreased growth performance of infected individuals and its subsequent economic effects. IBK is an economically important, lowly heritable categorical disease trait. Mass selection of unaffected animals has not been successful at reducing disease incidence. Genome-wide studies can determine chromosomal regions associated with IBK susceptibility. The objective of the study was to detect single-nucleotide polymorphism (SNP) markers in linkage disequilibrium (LD) with genetic variants associated with IBK in American Angus cattle.ResultsThe proportion of phenotypic variance explained by markers was 0.06 in the whole genome analysis of IBK incidence classified as two, three or nine categories. Whole-genome analysis using any categorisation of (two, three or nine) IBK scores showed that locations on chromosomes 2, 12, 13 and 21 were associated with IBK disease. The genomic locations on chromosomes 13 and 21 overlap with QTLs associated with Bovine spongiform encephalopathy, clinical mastitis or somatic cell count.ConclusionsResults of these genome-wide analyses indicated that if the underlying genetic factors confer not only IBK susceptibility but also IBK severity, treating IBK phenotypes as a two-categorical trait can cause information loss in the genome-wide analysis. These results help our overall understanding of the genetics of IBK and have the potential to provide information for future use in breeding schemes.

Highlights

Infectious Bovine Keratoconjunctivitis (IBK) in beef cattle, commonly known as pinkeye, is a bacterial disease caused by Moraxella bovis
The objective of this study was to detect single-nucleotide polymorphism (SNP) markers in linkage disequilibrium (LD) with genetic variants associated with IBK in Angus cattle
MIR7 has been characterized as a tumor suppressor in several human cancers. This SNP window lies in the region where putative QTLs that affect clinical mastitis at 12.60-35.89 cM and somatic cell scores at 12.601-29.77 cM, have been identified by Schulman et al [51] and Schnabel et al [52], respectively. These results indicate that genetic variant(s) that reside in this chromosomal region could be associated with bacterial disease such as IBK in cattle

Summary

Introduction

Infectious Bovine Keratoconjunctivitis (IBK) in beef cattle, commonly known as pinkeye, is a bacterial disease caused by Moraxella bovis. IBK is characterized by excessive tearing and ulceration of the cornea. IBK is considered the most important ocular disease in cattle production, due to the decreased growth performance of infected individuals and its subsequent economic effects. Infectious Bovine Keratoconjunctivitis (IBK), commonly known as pinkeye, is a highly contagious ocular bacterial cattle disease which occurs in cattle populations throughout the world. IBK is caused by the Gram negative bacterium Moraxella bovis [1] and is characterized by excessive tearing, inflammation of the conjunctiva, and ulceration of the cornea in one or both eyes. IBK is non-fatal; it is considered the most important ocular disease in cattle, due to the decreased growth performance of infected individuals.

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