Project description:The bat offers an alternative paradigm to the standard mouse and chick model of limb development as it has extremely divergent forelimbs (long digits supporting a wing) and hindlimbs (short digits and claws) due the distinct requirements of both aerial and terrestrial locomotion. We used a cross-species microarray approach to identify differentially expressed (DE) genes between the bat (Minniopterus natalensis) forelimb and hindlimb autopods at Carollia developmental stages (CS) 16 and CS17, and between the bat (CS17) and mouse (E13.5) forelimb autopods. Several DE genes were identified, including two homeobox genes, Meis2, a proximal limb-patterning gene, and Hoxd11, a gene involved in digit elongation. Both genes are significantly over-expressed in the developing bat forelimb as compared to the hindlimb and equivalently staged mouse forelimbs.