Marker Assisted Selection for Ascites Resistance in Broilers Using a Chromosome Z Locus

We have identified a chromosome Z locus associated with ascites phenotype in an experimental broiler line. In an initial study, we have shown we can alter the percentage of susceptible offspring through selection of dams and sires based on this locus. Ascites, a form of pulmonary arteriole hypertension, is a collection of adverse changes in a broiler chicken including high venous pressure, accumulation of fluids in the body cavity, and a flaccid heart resulting from the reduced ability for oxygen to be supplied to the organs. These events result in either processing plant condemnation or death from heart and lung failure. Losses to the poultry industry are estimated at $10-100 million/year. We performed a genome wide association study to identify chromosomal regions associated with ascites in the REL line developed by Dr. Anthony. One region we identified is on chromosome Z and includes the gene Myocyte enhancer factor 2c (MEF2C). This gene is involved in cardiac myogenesis. We developed a Taqman assay for a SNP in this region, and genotyped REL line birds. Ascites susceptibility appears to be more prevalent in REL line birds that are heterozygous for this region. Based on this we designed test matings based on genotypes for this SNP in the parents. Initial data indicate that offspring from matings that produce homozygotes are more resistant to ascites, compared to offspring from matings that produce heterozygotes.