Presentation Detail

Ecological Genetics and/or Genomics

Bay, Rachael A. [1], Palumbi, Stephen [1].

Genetic adaptation across a natural temperature gradient in reef-building corals.

Understanding potential mechanisms for adaptation to a changing climate is essential for accurate prediction of species response to climate change. In reef-building corals, thermal stress driven by climate change is one of the most commonly implicated factors in large-scale coral bleaching. However, bleaching susceptibility varies both between species and among individuals of the same species. Possible causes of variation in bleaching resistance include genetic adaptation, acclimation, or a combination of the two. In this study, we use a genomic approach to investigate the contribution of genetic adaptation to bleaching resilience in Acropora surculosa colonies from backreef pools on Ofu Island in American Samoa. These pools experience different temperature regimes, with one pool regularly exceeding 34 degrees celsius, much higher than expected bleaching temperature for the region. Previous studies have shown that individual colonies from these pools vary in their ability to resist bleaching when subjected to thermal stress. The aim of our study is to characterize individual genetic variants that may be associated with increased resilience to thermal stress. Using RNA-seq, we sequenced transcriptomes for 39 A.hyacinthus colonies across the natural temperature gradient on the backreef of Ofu. We also collected temperature data from each colony over the span of 6 months. From the full transcriptomes, we identified single nucleotide polymorphisms (SNPs) and tested for associations with temperature regime. We found that rare variants were maintained in the most thermally stressful environment, evidence for balancing selection in a heterogeneous environment. Genes with signals for natural selection represent a broad range of cellular pathways and processes that may be associated with thermal tolerance and bleaching resistance in A. surcolosa.

1 - Hopkins Marine Station of Stanford University, 120 Oceanview Blvd., Pacific Grove, CA, 93950, United States

Keywords:
thermal adaptation
corals
transcriptomics
Climate Change.

Presentation Type: Regular Oral Presentation
Session: 38
Location: Cotton C/Snowbird Center
Date: Saturday, June 22nd, 2013
Time: 4:30 PM
Number: 38005
Abstract ID:808
Candidate for Awards:W.D. Hamilton Award for Outstanding Student Presentation