Gene-Environment Interactions in Euryhaline Shore Crabs

Mount Desert Island Biological Laboratory, Bar Harbor ME

Investigators

Abstract

Shore crabs in the genus Carcinus are among the most invasive marine organisms known, easily establishing themselves in ecosystems far from their native origins. Apparently introduced through exchanges of ships bilge water, these crabs are highly tolerant of environmental extremes and thus can survive not only conditions during transport but also at their foreign destination. In these new environments, their aggressive nature can lead to disruptive changes in ecological relationships. To better understand the biology of Carcinus species, the proposed research will characterize at least 10,000 functional genes in the genome of the European shore crab Carcinus maenas, a common non-indigenous species in coastal regions of North America. A non-redundant set of these genes will be printed as DNA spots in microarrays on glass slides, representing a significant fraction of the crab genome. The initial physiological tests of environmental tolerance will focus on adaptation to salinity extremes and associated changes in gene activity. Gene products will be extracted from crab tissues, labeled with a fluorescent dye, and then added to the microarrays. Active genes will be visible as bright spots on the microarrays. Microarray results will be checked with an independent method to develop a gene expression signature for each experimental treatment. Conclusions based on Carcinus maenas will be compared with the Mediterranean shore crab Carcinus aestuarii, whose tissue samples will be obtained through collaboration with investigators at the Institute of Oceanography and Fisheries in Dubrovnik, Croatia. This study of gene expression changes in response to environmental stimuli may lead to the identification of weak links in the physiology of non-indigenous shore crabs, establishing possible targets for future population control and restoration of ecological balance in coastal ecosystems affected by these invasive animals. The proposed research represents the first known application of microarray analysis to a study of gene-salinity interactions in marine organisms. The PI is actively involved in training undergraduate and graduate students from his own institution as well as other institutions within and outside of the USA, and has developed a core curriculum for molecular techniques training and will include a female student from Croatia be the first summer participant in the research. This research will be of interest to marine biologists, comparative physiologists as well as molecular biologists interested in gene regulation.