Author contributions
JA wrote the first draft of the manuscript, did field work, the
experiments, wet lab work and data analyses. PR contributed
substantially to data analyses. HG performed RNA-seq library preparation
with JA. DW did preliminary analyses of MiSeq transcriptome data that
were used to decide on pooling for HiSeq. OSA oversaw the lab work at
University of Iceland. SW conceived and designed the study, did field
work, helped with the temperature shift experiment, and contributed to
data analyses and manuscript writing.