Hoxb13 and Meis1 (IMAGE) UT Southwestern Medical Center Caption In this image of adult mouse hearts in which the genes Hoxb13 and Meis1 were knocked out for the study, cardiomyocytes display features normally just seen in newborn mouse hearts. Credit UTSW 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.