Digital Imaging

This is interesting. Says National Geographic:

Sharks Have Genes for Fingers and Toes

The basic process for developing fingers and toes in land animals may have existed for more than 500 million years in shark genes, according to a new study.

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.

I wonder if, as Stephen Jay Gould would say, you could rewind the tape of evolution and start over, would sharks today have been able to type? And what would that mean for humanity if they could? I guess sexual predators wouldn't be the only ones you'd have to watch out for in chatrooms....