Investigation of Single Nucleotide Polymorphisms for UTS2D and AGTR1 for Their Association with Ascites in Chickens

Idiopathic Pulmonary Arteriole Hypertension (IPAH) in humans is a condition characterized by sustained elevated blood pressure in pulmonary arteries that eventually results in right-ventricular failure and death. In chickens, ascites is the commercial name for IPAH. Our genome-wide association study showed association of a region on chromosome 9 with ascites. Analyses of multiple breeding lines with two VNTRs from this region supported a female-specific association with ascites. Within this region, two candidate genes- UTS2D (Urotensin 2 Domain Containing) and AGTR1 (Angiotensin II Type 1 Receptor) were identified that are involved with hypoxic response and vasoconstriction. Sequence analyses identified Single Nucleotide Polymorphisms (SNPs) for both genes segregating in the resistant and susceptible chicken lines. TaqMan assays were developed for some of the identified SNPs to determine the association of these genes with susceptibility and resistance to ascites in experimental and commercial chicken lines. Haplotype tests were performed to ascertain the linkage among the identified SNPs. Our current data indicate that the SNPs for these two genes do not have a significant association with the disease and that they may not serve as reliable QTLs for ascites in chickens.