University of Richmond

Sponge Research Absorbs Husband-Wife Research Team

April 20, 2005

University of Richmond biology professors April and Malcolm Hill are at the forefront of an increasing research interest in sponges.

Sponges are among the most primitive animals, and studying them gives scientists a chance to look backward in terms of evolution, says April Hill, a developmental geneticist.

The Hills research on sponges has shed new light on the genes of sponges. Though sponges are primitive creatures that strongly resemble the earliest animals to appear on the planet, the Hills have shown they nevertheless carry sophisticated genes that in other creatures control the growth of eyes, the brain and the central nervous system.

"It's as if sponges have all these tools, a black box of genes, but still have very simple bodies," says Malcolm Hill.

Sponges have eye, brain and nervous system genes, but don't use them to make eyes, brains or a nervous system, the Hills studies show.

In spite of not using some of them, sponges contain genes very much like those that play a role in the development of human sensory systems.

Theres not a whole heck of a lot of difference between sponge genes and human genes, says April Hill. And we share 75 percent of their genetic history, says Malcolm Hill.

Indeed, the husband-and-wife research team is willing to go so far as to say, with tongues firmly in cheek, that if sponges did make full use of the genes they carry, they might really resemble the popular cartoon character Sponge Bob, Square Pants (minus the pants, of course).

"As it turns out, sponges have the genetic potential that could lead to things like eyes, legs and arms," April Hill says.

"The evidence is pretty strong that the common ancestor of all animals was very sponge-like," Malcolm Hill says. "We can learn a lot about the history of the origins of animals by studying the most primitive ones."

In one set of experiments, described in the most recent issue of Development Genes and Evolution, the Hills identified and isolated a gene from sponges (the Bar/Bsh gene) that in more advanced animals plays a key role in brain and nervous system development.

In ongoing research, they are examining genes (Pax genes) that are involved in eye development in more complex animals. It appears that these sponge Pax genes can produce eyes in other animals without performing that role in the sponge itself.

The two scientists credit the cartoon character with imbuing their research with a cool-factor to their children, along with generating more awareness among the general public that sponges are animals and not plants, "even if they don't live in a pineapple," Malcolm Hill says.

Sponge Bob's popularity aside, the two have noticed that sponges are also attracting more attention among scientists. "Sponges are important creatures for a number of reasons. They produce promising anti-cancer drugs, they are the most ancient animal group and provide clues about our own evolution, they play important ecological roles in marine systems," April Hill says.

Most students want to study humans, sharks or dolphins when they come in, Malcolm Hill says, but once they get introduced to sponges, a lot of them come around. Were converting one person at a time to the sponge world.