244K array Comparative Genomic Hybridization for the characterization of CNVs among inbred Fayoumi, inbred Leghorn, Line A broiler, and Line B broiler chicken

Chromosomal structural variation can cause alterations in gene dosage and gene regulation between genomes. Structural variants producing a change in the number of copies of a genomic region are termed copy number variants (CNVs). CNVs have been demonstrated to have causative effects on both Mendelian and complex traits, including susceptibility to infectious diseases. We are interested in mapping CNVs to domesticated chicken breeds to help determine structural variation between genomes that influences economically important traits. For this study, Fayoumi, Leghorn, Line A broiler and Line B broiler chicken were chosen. Fayoumi and Leghorn chickens were selected as these two breeds harbor different responses certain pathogens like Avian Influenza Virus and coccidiosis; Broiler Line A and Line B indivduals were chosen as they harbor different intestinal colonization loads to the bacterium Campylobacter jejuni. Campylobacter genetic Line A and genetic Line B are from a commercial producer have been previously described as either resistant (Line A) or susceptible (Line B). Highly inbred chicken lines Fayoumi M15.2 (n=6) and Leghorn GHs6 (n=6) and broilers from Line A (n=24 individuals in pools of 4) and Line B (n=24 individuals in pools of 4)were subjected to array Comparative Genomic Hybridization (aCGH). Each sample was normalized to a Red Jungle Fowl reference. CNVs for each individual and between lines were determined. The major goal of this study was to discover and characterize CNVs in chickens to further narrow in on Quantitative Trait Loci (QTLs) affecting disease response. For the test DNA in Fayoumi and Leghorn, samples from 6 inbred Fayoumi and 6 inbred Leghorn individuals were used; For the test DNA in the Campylobacter genetic lines, samples from 24 individual broilers of Line A (in pools of 4) and 24 individual broilers of Line B (in pools of 4) were used. For the reference DNA, Red Jungle Fowl line UCD001 was used from a self-self hybridization.