Fruit Fly Strains (IMAGE) University of Utah Health Caption Natural variations in the genetic background of 200 strains of fruit flies contribute to differences in severity of a disease model for retinitis pigmentosa. Credit University of Utah Health Usage Restrictions With credig 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.