Our collaborative group at the University of Arkansas has identified chromosomal regions in chickens associated with susceptibility to Pulmonary Arterial Hypertension (PAH) and ascites in broilers. One of these regions on chromosome 9 contains the genes for AGTR1 (Angiotensin II Type 1 Receptor) and UTS2D (Urotensin 2 Domain containing). Others have shown association of these genes with PAH in humans. Our sequence analyses of these gene regions have identified Single Nucleotide Polymorphisms (SNPs) for both genes segregating in our resistant and susceptible ascites lines. We identified two alleles of AGTR1 that show association with ascites susceptibility in our lines and commercial broiler lines. We have identified at least 5 alleles for UTS2D in our lines. SNPlotyping for these alleles is underway. These analyses will help us determine the contributions of these two genes to PAH and ascites in broilers. Additionally, advances in understanding of the genetics of PAH in chickens will also extend our research on the suitability of the chicken as a medical model for PAH in humans.