Fish can develop fingers and toes

Posted on August 16, 2007
Tags: Facts |

Fascinating.

Sharks Have Genes for Fingers and Toes

Researchers identified genetic activity in spotted catsharks embryos that signal the creation of digits. The discovery pushes back the date of the evolutionary “fin to limb” advance by some 135 million years. When a gene—essentially a set of instructions—is translated into a trait, such as red hair or an arm, it is said to be expressed. Scientists have long believed that the gene for digit development was first expressed some 365 million years ago in the earliest tetrapodsthe first vertebrates to walk on land. (Related: “Ancient Fish Fossil May Rewrite Story of Animal Evolution” [October 18, 2006].) But the new study suggests the finger-and-toe gene was first expressed much earlier, in fish—though not to such an extent that it yielded actual digits. “We’ve uncovered a surprising degree of genetic complexity in place at an early point in the evolution of appendages,” study leader Martin Cohn of the University of Florida said in a statement. The findings appear this week in the journal PLos ONE.

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