Male Mice Model Human Speech Defect (IMAGE) Duke University Caption Male mice carrying a specific genetic mutation have difficulty switching from singing a simple mating song (lower sonogram), to a more complex mating song (upper sonogram). Researchers believe these mice might help shed light on genetic factors contributing to speech disorders in humans. Credit Image Courtesy Erich Jarvis, Duke University 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.