Primitive fish may shed light on evolution of limbs
Once thought to be extinct, the coelacanth (through its DNA) is aiding scientists in their growing understanding of evolution. When inserted into mice, the fish's DNA causes the mammals to grow limbs. In the fish the same DNA codes for fins, not limbs.
The genome of a primitive fish that was once thought to have died when the dinosaurs did has now been sequenced by scientists — and when put into mice, some of the fish DNA caused mice to sprout limbs.
The new analysis, described today (April 17) in the journal Nature, could help to reveal how primitive fish swapped their fins for limbs when they moved from land to sea.
The fish, called a coelacanth, seems to carry snippets of DNA that can turn on genes that code for forelimbs and hind limbs in mice. The new discovery could shed light on how four-legged creatures, called tetrapods, evolved. [Image Gallery: The Freakiest Fish]
The coelacanth was once thought to have gone extinct about 70 million years ago, roughly around the time dinosaurs vanished. But in 1938, a fish trawler brought a bluish-purple, 3.3-foot-long (1 meter) fish with fleshy fins to the South African naturalist Marjorie Courtenay-Latimer. It turned out to be an African coelacanth.