These findings are reported in a study in Nature by Parker et al. These researchers performed a genome-wide sequence analysis for 22 mammals that independently evolved echolocation. As the authors state, "[t]his study represents the first systematic attempt to provide a framework for the genomic analysis of sequence convergence associated with independently shared phenotypes."
The investigators discovered a DNA sequence convergence in 200 regions of the genomes of these mammals. They saw a strong convergence between bats and the bottlenose dolphin in genes linked to hearing or deafness. They also observed unexpected convergence in genes linked to vision. Most of the convergent genetic loci have no known role in echolocation; many of these are poorly characterized in function, so they may play roles in echolocation. Finally, some of the genes of known function are unlikely to play roles in echolocation but may be associated with characteristics that correlate with echolocation in some way.
Very cool! Below is an excerpt from a Nature News write-up summarizing the original article.
NATURE | NEWS
Convergent evolution seen in hundreds of genes