Scientists and Researchers

Principal Investigator

Professor, Marine Biology and Fishery and Director of National Resource for Aplysia

Senior Resource Manager

Co-Principal Investigator

Our research on the invertebrate snail involves its nervous system. The nervous system of any animal is controlled by electrical and chemical signals that flow between its cells. Many of these signals develop over time as the animal matures (for example, eyesight in human infants develops slowly over time as the electrical connections between nerve cells in the brain develop). In Aplysia, we're interested in studying how hormones influence the development of those signals in growing snails. In particular, we're interested in a group of neurosecretory cells called “bag cells” that, once they develop their mature complement of electrical signaling machinery, release a hormone that causes these hermaphroditic animals to lay eggs. Experiments show that the necessary electrical machinery for release of the Aplysia's egg laying hormone becomes present in the bag cells only just before sexual maturity. In this way, the immature animal is guarded against premature release of the hormone and unnecessary egg laying.

Patrick J. Walsh

Aplysia californica are of great importance to the genome project (hyperlink to genome project). When one sequences a genome, one typically chooses a single individual of a species. However, since every individual has both maternal and paternal genes, and these can be a little different (e.g., from which parent does the dominant brown eye gene come from vs. the recessive blue eye gene). These differences are known as polymorphs. When the sequencer reads the genes it sees both the maternal and paternal genetic information, and in fact if these are slightly different, it will report back ambiguous results at the location of the difference. Therefore, the best way to get that single individual to be sequenced is to try to inbreed away those differences. Without the National Resource for Aplysia, we would be taking our chances by nabbing an individual from the wild. With the hatchery, just for the genome project, we are inbreeding selected individuals to probably the fifth or sixth generation, in order to breed away most (probably not all) of the polymorphisms to minimize the ambiguity in the DNA sequences.