Hopkins Marine Station Student Paper

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Title: Population structure of Tegula funebralis along the west coast of the United States
Student Author(s): Blazyk, Katherine
Faculty Advisor(s): Palumbi, Stephen
Pages: 28
Location: final Papers Biology 175H
Date: June 2003
Abstract: Potential for gene flow in marine environments is often much higher than what is actually observed, due to various barriers to dispersal. Understanding the divisions between populations of organisms is important to fishery regulations and designing effective marine reserves. Tegula funebralis have a pelagic larval phase, lasting 5-14 days, giving them a moderate potential for dispersal. Samples ranging from Oregon to Santa Barbara were collected from seven geographic locations. A 700 base pair region of the mitochondrial cytochrome oxidase I gene (COI) was sequenced for an average of 9 individuals from each location. Comparing these sequences, there is no clear overall population structure, although there seem to be some slight patterns corresponding to geographic location. In particular, snails from Oregon are more similar to each other and are more different from snails from other populations, suggesting a lower level of dispersal between T. funebralis from Oregon and the more southern locations. These smaller signals could not be shown to be significant with the current sample sizes, using FST values or chi-squared tests, and had p values of between 0.07 and 0.10. Overall, there appears to be a fairly high level of gene flow across the range studied, which makes it unlikely that there are major barriers to dispersal in this range. However, there may be subtle population structure in T. funebralis along the west coast of North America that will emerge when larger sample sizes from each location are used, a larger portion of the gene is sequenced, and populations further to the north and south are sampled.