Genetic Analysis Uncovers Shared Evolutionary History of Fish Fins and Vertebrate Limbs

Published:14 Nov.2021 Source:University of Chicago Medical Center

In a study published this week in the Proceedings of the National Academy of Sciences, researchers from the University of Chicago and the Andalusian Center for Developmental Biology in Spain used genetic editing tools to show how a gene that controls the growth of bones at the terminal end of fish fins play the same role in forming fingers and toes in four-legged creatures. The same gene also controls this process both in paired fins, which are the progenitors to limbs, and the single, unpaired dorsal fin common to all fish that evolved before paired fins. This suggests that the last common ancestor between ray- and lobe-finned fish nearly 500 million years ago already had the genetic toolkit to shape their appendages, shared to this day by fish and four-legged vertebrates.

‘There’s this deep homology or similarity between fins and limbs, something ancient in structures that really don’t look alike,’ said Neil Shubin, PhD, the Robert R. Bensley Distinguished Service Professor of Anatomy at UChicago and co-author of the new study. ‘We’re showing a deeply conserved, deeply ancient and preserved gene function that’s been around for hundreds of millions of years in vastly different structures. So, the molecular toolkit is ancient, and it does the same thing in different kinds of animals.’