Phylogenomic analyses reveal latitudinal population structure and polymorphisms in heat stress genes in the North Atlantic snail Nucella lapillus.
North Atlantic rocky intertidal species have been shaped by repeated glaciations and strong latitudinal temperature gradients, making them an excellent system to study postglacial phylogeography and thermal tolerance. Population genetics data from northwestern Atlantic species, however, often show patterns inconsistent with the prediction that high dispersal should generate weaker genetic structure among populations. Here, we used next-generation sequencing restriction-associated DNA tags (RAD-seq) and a transcriptome assembled from RNA-seq data to analyse the genetic structure of northwestern Atlantic populations of the low-dispersal intertidal snail Nucella lapillus. Although previous studies in this region have detected almost no genetic structure in N. lapillus, our phylogenomic approach identified a well-supported split between northern and southern clades. By comparing RAD-seq data and our transcriptome assembly, we identified thousands of fixed single-nucleotide polymorphisms (SNPs) between these latitudinal clades that map to protein-coding genes, including genes associated with heat stress tolerance. These fixed SNPs might represent loci under selection for different thermal regimes in the northwestern Atlantic.
Ecology and Evolutionary Biology, Brown University, 80 Waterman St., Box G-W, Providence, RI, 02912, USA; Marine Science Center, Northeastern University, 430 Nahant Road, Nahant, MA, 01908, USA.
Nathaniel D
ND
Chu
Stefan T
ST
Kaluziak
Geoffrey C
GC
Trussell
Steven V
SV
Vollmer
D000818:Animals; D019143:Evolution, Molecular; D005828:Genetics, Population; D018869:Heat-Shock Response / Q000235:genetics*; D006358:Hot Temperature; D008281:Maine; D008404:Massachusetts; D009674:Nova Scotia; D010802:Phylogeny; D058974:Phylogeography; D020641:Polymorphism, Single Nucleotide; D012237:Rhode Island; D017422:Sequence Analysis, DNA; D012908:Snails / Q000235:genetics*; D059467:Transcriptome
Nucella lapillus; adaptation genomics; phylogeography; restriction-associated DNA tags; thermal adaptation; transcriptomics