Title: ``Combining mapping and arraying: a novel approach to candidate gene identification''
Speaker: Dr. Marta Wayne, University of Florida
Place: LILLY G126; Tuesday, 4:30pm


A novel combination of QTL mapping and microarray analysis was used to identify N candidate genes for ovariole number, a quantitative trait , in Drosophila melanogaster. Ovariole number is related to evolutionary fitness which has been extensively studied, but for which few a priori candidate genes exist. A set of recombinant inbred lines were assayed for ovariole number and QTL analyses for this trait identified 5286 positional candidate loci. Forty deletions spanning the QTL were employed to further refine the map position of genes contributing to variation in this trait between parental lines, with six deficiencies showing significant effects and reducing the number of positional candidates to 548. Parental lines were then assayed for expression differences using Affymetrix microarray technology and ANOVA was used to identify differentially expressed genes in these deletions. Thirty-four genes were identified that showed evidence for differential expression between the parental lines, one of which was significant even after a conservative Bonferroni correction. The list of potential candidates includes 5 genes for which previous annotation does not exist, and therefore would have been unlikely choices for follow-up from mapping studies alone. The use of microarray technology in this context allows an efficient, objective, quantitative evaluation of genes in the QTL and has the potential to reduce the overall effort needed in identifying genes causally associated with quantitative traits of interest.