Two Brother Mice (IMAGE) Université de Genève Caption Two brother mice pups from the same litter. The one carrying a mutated Hoxd3 gene is on the left. Credit © UNIGE 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.