Fruit Flies with Genetic Markers (IMAGE) University of Rochester Caption The researchers use genetic markers to track segments of the X chromosome that they move from one species of Drosophila (fruit fly) into a different species in order to find X-linked genes that cause male sterility. Genetic markers that affect eye color are located on the X chromosome, so the researchers start with Drosophila mauritiana that have two genetic markers -- giving them dark red eyes, left -- and cross them to white-eyed Drosophila simulans. Credit University of Nebraska photos / Rodolfo Villegas Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.