Human fingers evolved with same gene used to grow fish fins

William Atkins
Friday, 02 November 2007 20:47

Science - Biology

Swedish-English researcher finds overwhelming evidence that fingers on humans evolved from the same gene that is found to grow fins on the Australian lungfish.       

Such a discovery helps to add credence to the theory that fingers and toes evolved from fins of fish that lived hundreds of millions of years ago, and had lungs and lobe-fins. Their study looked at fossil evidence from these ancient fish, and from four species of similar fish that still live today. One of these living fish is the Australian lungfish (Neoceratodus forsteri).

From the study headed by Swedish-English palaeontologist Per Ahlberg, professor of evolutionary organismal biology at Uppsala University in Sweden, the fins from the Australian lungfish develop in two stages, with the gene called Hoxd13 controlling the growth of fine bones (radials) at the edge of the fins.

The growth of fingers and toes in tetrapods, the group of land animals with a backbone, including humans, is also a two-stage process with the same gene Hoxd13 controlling the growth of fingers and toes.

Scientists thought that fingers and toes evolved from amphibians about 380 to 365 million years ago. However, this study strongly disagrees with such a connection.

Ahlberg commented in the article “Gene proves fingers formed from fins” in the October 27, 2007 issue of New Scientist magazine, “It is powerful evidence that the radials of Neoceratodus and the digits of the tetrapod are essentially the same thing.” He went on to say, “Evolution has worked by tinkering with an existing structure rather than coming up with something fundamentally new.”

Dr. Ahlberg presented the findings of his study at the October 17-20, 2007 meeting of the Society of Vertebrate Paleontology in Austin, Texas, United States.