Their studies were performed in chickens, and the gene, called Tbx4, appears to be involved in limb formation in mammals as well, including humans. (salk.edu)
But they are extraordinarily hard to understand, as was made clear last week when molecular biologists for the first time described the regulatory backups for two genes involved in mammalian limb formation. (sciencemag.org)
Both fish and land animals possess clusters of Hoxa and Hoxd genes, which are necessary for both fin and limb formation during embryonic development. (sciencedaily.com)