New species can form when population adapt to contrasting habitats reordering genetic variation in these populations to suit these habitats. However, we view the world through phenotypes not genotypes, thus sometimes thing that have been classified as separate species, or ecotypes, are found to be genetically homogenous. This project will test our preconceived notions about different ecotypes of the sea snail, Littrorina saxatilis. In Sweden, we have extensively studied two ecotypes; crab-resistant and wave-resistant snails. Yet, there are much more variation in habitat and morphology than we have studied at our field site. We have sampled snails from 200 random sites near the Tjärnö Marine Station, with the goal of identifying genetic clusters which we can associate to habitats, thereby more accurately defining snail ecotypes in Sweden. This computing project will process whole genome sequence data from 120 sea snails (Littorina saxatilis) that were collected from random sites around the Tjärnö Marine Laboratory, Sweden. This continuation will use the genetic data from these snails and SNP genotyping data from nearly 1,400 other snails, to identify genetic groups and investigate statistical correlations among genetic, phenotypic and environmental variation. The end goal is to construct a detailed map of L. saxatilis diversity on the Swedish West Coast.