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

We have identified a locus on the chromosome Z associated with ascites phenotype in an experimental broiler line. Through this study, we have shown that we can alter the percentage of resistant offspring through selection of dams and sires based on this locus. Ascites, a form of pulmonary arteriole hypertension, is an accumulation of adverse effects in a broiler chicken.  It is most commonly associated with 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 leading to death. 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 relaxed (REL) line developed by Dr. Anthony. One region identified is on chromosome Z which includes the gene Myocyte enhancer factor 2c (MEF2C) necessary for cardiac myogenesis.  We have developed a Taqman assay for a SNP in this region, and genotyped REL line birds, for which we created test matings based on genotypes for this SNP in the parents. Initial data indicate heterozygous offspring produced from homozygous sires result in an increase of susceptibility for ascites, while heterozygous sires produce offspring that has an increase of resistance.