FULLERTON : Scientists to Study Sea Squirt Sexuality

Three Cal State Fullerton science professors hope their studies of an ancient sea creature will one day lead to breakthroughs in human reproduction. Now biology professor Robert Koch and chemists Charles Lambert and Christina Ann Goode have received grants totaling more than $300,000 from the National Institute of Child Health and Human Development and the National Science Foundation to carry on their study of the sea squirt.

Properly known as an ascidian, the sea squirt is a tiny member of the family of invertebrates--creatures without a spinal column--that is most closely related to humans, the scientists said.

Sea squirts are of special interest for researchers studying human reproduction because they are hermaphrodites: They release both sperm and eggs needed for the fertilization process, stimulating other ascidians to do the same.

Koch said the process by which the sperm fertilizes the egg in ascidians is similar to the way human reproduction works. In both ascidian and humans, after a sperm enters an egg to fertilize it, the egg gives off a chemical that makes it almost impossible for another sperm to penetrate it.

But about 70% of fertilized eggs in humans die quickly without developing into a fetus. About 5% to 7% of these deaths are believed to be the result of two or more sperm penetrating the same egg, a phenomenon known as polyspermy.

The group hopes to discover what causes the ascidian eggs to release an enzyme that prevents more than one sperm from piercing the egg wall.

Locally, a type of sea squirt lives in Los Angeles Harbor.