2 High-resolution QTL Mapping Reveals Sign Epistasis Controlling Ovariole Number between two Drosophila Species Virginie Orgogozo * , Karl W. Broman † and David L. Stern * * Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544 † Department of Biostatistics, Johns Hopkins University, Baltimore, MD 21205 Genetics: Published Articles Ahead of Print, published on February 19, 2006 as 10.1534/genetics.105.054098