Meeting Abstract

96.6  Monday, Jan. 6 14:45  Heritability of dispersal-related traits and gene expression in larvae of reef-building corals DAVIES, S/W*; MATZ, M/V; Univ. of Texas, Austin; Univ. of Texas, Austin daviessw@gmail.com

Reef-building corals are declining as a result of both direct and indirect anthropogenic influences, including elevated sea surface temperatures due to global warming. Range shifts enabled by enhanced dispersal capability is one of the most likely mechanisms by which a coral species can escape the adverse effects of climate change. Since the majority of corals release gametes into the water producing planktonic larvae, selection for dispersal potential is limited to optimizing larval traits and can be investigated through classical quantitative genetics and functional genomics using laboratory-reared larvae. We hypothesize that climate change selects for genotypes capable of longer-range dispersal favoring behavioral and metabolic adaptations that lower larval responsiveness to settlement cue early in life and enable extended planktonic larval duration. We have generated 20 full-sib larval families and quantified four traits that are hypothesized to be relevant for determining larval dispersal potential: early responsiveness to settlement cue, rate of lipid loss, rate of protein loss and red fluorescence. For two of these traits (settlement and fluorescence), considerable broad-sense heritability was observed (> 0.4). To identify the genes underlying this variation, we used RNA-seq to profile gene expression in all larval families prior to exposure to the settlement cue and also in young recruits post settlement, representing two life history stages. We observe significant signatures of heritability in gene expression at both life stages with most of the heritable gene expression variation associated with regulatory processes. These data elucidate the molecular mechanisms underlying dispersal potential, which may be the targets of natural selection under climate change.