MOORE, Beth*; TAGMOUNT, Mani; STILLMAN, Jonathon; Romberg TIburon Center, San Francisco State University: Latitudinal variation in transcriptome profiles following heat and cold stress of the porcelain crab, Petrolisthes cinctipes

Organismal responses to thermal stress are an important determinant of how climate change may impact natural populations. Organisms vary in their response to thermal stress depending on previous thermal exposure, including mean body temperature and frequency of extreme temperatures. Across the California to British Columbia latitudinal gradient, mean temperatures of intertidal organisms are similar, but frequency of extreme temperatures varies. We hypothesize that organisms distributed across this latitudinal range will respond differently to thermal stress. We examined responses to acute heat or cold stress in three populations of the porcelain crab, Petrolisthes cinctipes, from Monterey, CA, Cape Arago, OR, and Bamfield, B.C. Crabs were collected from each site, and were thermally ramped over 4h to 30-31�C (heat stress), or 0-2�C (cold stress), or 10-15�C (control). Following the thermal ramp, crabs from all three treatments were held for 6h at 10-15�C, at which time hepatopancreas tissue was dissected into RNAlater (Qiagen) and stored at -20�C. RNA was purified using Qiagen RNeasy spin columns, and reverse transcription was used to synthesize amino-allyl cDNAs, which were labeled with Cy3 or Cy5 dye and hybridized on microarrays using a modified loop design. The microarray used for this study is constructed from a 13,824-clone cDNA library created from various types of P. cinctipes tissue from specimens exposed to diverse thermal conditions. Fluorescence data were log transformed and Loess normalized. These data were used in R/maanova to identify genes that were differentially expressed between the thermally stressed (heat or cold) and control specimens for each site, and across the three collection sites. This research was supported by NSF IOB-0533920 and JGI CSP to JHS.