SCIENCE LAB SPECIAL ; AN ANCIENT LINEAGE

 

The ancient back story of the sea's gooiest creature. The hagfish, a deep-sea scavenger about the size and shape of a tube sock, has the curious ability to smother itself in its own snot.

The mucus is a defense mechanism, released into the water when the fish, feels threatened.

Once it hits seawater, a tiny amount of the ooze expands to 10,000 times its original size in a fraction of a second, forming a tenacious web of goo. Shark trying to take a bite of hagfish will find itself suddenly unable to breathe, its gills clogged with slime.

But the hagfish itself is similarly enmeshed.

The hagfish finds the process of being captured by scientists late at night on boats in the black ocean a bit stressful : The situation sets off the mucus reaction.

Juan Pascual Anaya, a biologist at the University of Malaga in Spain who has spent summers collecting hagfish off the coast of Japan, describes having to strip the elastic gel off the animals with his hands. '' We have to be removing the mucus all the time on the ship or they will die,'' he said.

All this scraping was in pursuit of an evolutionary unknown : what the hagfish's genome can tell us about the earliest vertebrates. The hagfish has no jaw, making it part of a group that diverged long ago from the ancestors of jawed vertebrates like the sharks, giraffes and humans.

Dr. Pascual-Anaya and other scientists have now reported in the journal Nature Ecology & Evolution that they have sequenced the genome of the hagfish.

The evidence they found suggested that jawless fishes diverged from those with jaws more than half-billion years ago.

The World Students Society thanks Veronique Greenwood.