Meeting Abstract

S7.5  Tuesday, Jan. 5  Environmental Imprinting (Epigenetics) and Adaptation in Antarctic Marine Invertebrates. MARSH, Adam*; KENDALL, Lindsay; GUIDA, Stephanie; University of Delaware; University of Delaware; University of Delaware amarsh@udel.edu

DNA methylation is an important epigenetic information system. Many environmental factors such as temperature and nutrition have been shown to impact patterns of genome methylation in animals with a net effect of altering gene expression rates. Genomic distributions of 5-methylcytosine residues are replicated during cell division and thus germ-line epigenetic modifications can be transferred across subsequent generations. We are assessing the potential for DNA methylation to be involved in adaptations to polar conditions of low temperature and limited food in two macroinvertebrates: the sea urchin Sterechinus neumayeri and the polycheate Capitella perarmata. In addition, we have broadly surveyed a range of temperate invertebrate phyla for the prevalence of DNA methylation. We have found that both polycheates and sea urchins have substantial methyl-cytosine compositions, and that patterns of genome methylation are responsive to experimental temperature manipulations. Shifts in methylation around specific loci could play a large role in altering metabolic activities as has been found in model animal systems, particularly in terms of glucose metabolism as determined by the IGF-2 locus. DNA methylation may serve as a cellular memory system by which strict environmental constraints in polar habitats are imprinted upon a genome to balance gene expression activities. Thus, an epigenetic mechanism of gene expression regulation could be an important determinant of phenotype fitness in polar organisms.