miRNAs Play a Key Role in Sexual Differentiation in the Fruit Fly (image) Cold Spring Harbor Laboratory Share Print E-Mail Caption Cold Spring Harbor Laboratory researchers have found that miRNAs, short RNA molecules, are responsible for sexual differences in fruit flies. Shown here are testes from a male fruit fly where a hormone that controls a key miRNA has been inactivated. The abnormal testes fail to make sperm. They now produce sex determinants (shown in red) that are found in the ovaries of female flies. Credit D. Fagegaltier/ Cold Spring Harbor Laboratory Usage Restrictions None Share Print E-Mail 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.