Evaluation of two promising genes from the target region of SSC13 with susceptibility towards the ETEC F4ac adhesion in pigs

<p>Enterotoxigenic <i>Escherichia coli</i> (ETEC) expressing F4 fimbria is the major pathogenic bacteria causing diarrhoea in neonatal and post-weaned piglets. Based on our previous GWAS results from 301 pigs in a two generation family-based population, two promising candidate genes (<i>HEG1</i> and <i>ITGB5</i>) from a 0.65 Mb region on pig chromosome 13 for susceptibility to ETEC F4ac infection were investigated for the presence of possible causative mutations. A total of 23 polymorphisms in their coding regions were identified, and two previous uppermost GWAS significant SNPs (ALGA0072075; GenBank NC_010455.4:g.145009857 A > G) were also chosen for genotyping in the three pig breeds. The genotyping data and association analysis results showed that a C to T polymorphism in exon7, and a G to T polymorphism in exon14 of the <i>HEG1</i> gene significant increased the effects on the ETEC F4ac adhesion traits (<i>p</i> = 2.853E − 11; <i>p</i> = 1.410E − 09). Although the identified polymorphisms were not causal mutations, these results indicate that the <i>HEG1</i> gene is an important adhesion molecule, and it could serve as a genetic marker for selecting ETEC F4ac-resistant pigs in breeding programmes.