Meeting Abstract

P1.48  Friday, Jan. 4  Genotypic and Epigenetic Response to Community Structure in Spartina alterniflora ROBERTSON, MH*; RICHARDS, CL; HUGHES, AR; Univ. of South Florida mhr@mail.usf.edu

Community structure critically impacts species fitness via mechanisms such as competition and cooperation. The success of organisms in a community is influenced by genotypic diversity of the species present and of the community as a whole. Genotype is typically thought of as the primary determinant of phenotype, where environmental pressures (i.e. natural selection) influence which genotypes increase in the population. However, a growing body of evidence suggests that phenotype may also be influenced by epigenetic modulation of gene expression in response to environmental stimuli (e.g. via DNA methylation). Furthermore, biotic interactions have an impact on epigenetic variation and epigenetic variation can influence species interactions. Few studies have examined epigenetic responses in natural populations, and the importance of epigenetic variation in natural populations remains largely unknown. In this study, five genotypes of Spartina alterniflora were grown in a natural environment in monoculture and polyculture. We found differences in density and height in three of the five genotypes depending on the genotypic diversity of the experimental population. We also tested for an effect of genotypic diversity on DNA methylation patterns in these genotypes using methylation-sensitive AFLP markers. Differences in the methylation pattern among genotypes and environments suggest a differential ability for genotypes to respond epigenetically to community structure, and potential for natural selection to act on that variation.