Abstract
Global climate change is projected to accelerate during the next century, altering oceanic patterns in temperature, p H and oxygen concentrations. Documenting patterns of genetic adaptation to these variables in locations that currently experience geographic variation in them is an important tool in understanding the potential for natural selection to allow populations to adapt as climate change proceeds. We sequenced the mantle transcriptome of 39 red abalone ( H aliotis rufescens ) individuals from three regions ( M onterey B ay, S onoma, north of C ape M endocino) distinct in temperature, aragonite saturation, exposure to hypoxia and disease pressure along the C alifornia coast. Among 1.17 × 10 6 Single Nucleotide Polymorphisms ( SNP s) identified in this study (1.37% of the transcriptome), 21 579 could be genotyped for all individuals. A principal components analysis concluded that the vast majority of SNP s show no population structure from M onterey, C alifornia to the O regon border, in corroboration with several previous studies. In contrast, an F ST outlier analysis indicated 691 SNP s as exhibiting significantly higher than expected differentiation (experiment‐wide P BLAST annotation, 34 of which contained more than one outlier SNP . A large number of these genes are involved in biomineralization, energy metabolism, heat‐, disease‐ or hypoxia‐tolerance. These genes are candidate loci for spatial adaptation to geographic variation that is likely to increase in the future.