A fundamental issue in speciation research is to evaluate phenotypic variation and the genomics driving the evolution of reproductive isolation between sister taxa. Above all, hybrid zones are excellent study systems for researchers to examine the association of genetic differentiation, phenotypic variation and the strength of selection. We investigated two contact zones in the marine gastropod Littorina saxatilis and utilized landmark-based geometric morphometric analysis together with amplified fragment length polymorphism (AFLP) markers to assess phenotypic and genomic divergence between ecotypes under divergent selection. From genetic markers, we calculated the cline width, linkage disequilibrium and the average effective selection on a locus. Additionally, we conducted an association analysis linking the outlier loci and phenotypic variation between ecotypes and show that a proportion of outlier loci are associated with key adaptive phenotypic traits.
LittorinaSaxatilis_AFLPs
The file LittorinaSaxatilis_AFLPs.txt correspond to the AFLP dataset used in this manuscript where we studied a hybrid zone of the marine gastropod Littorina saxatilis. It contains AFLP genotypes (1 for presence, 0 for absence, 9 for missing data). The first 4 columns contain ISLAND, ECOTYPE, POPULATION and INDIVIDUAL information. The rest of the columns represent the genotypes (0,1) of 1167 AFLP loci studied.
The first row contains the loci names according to the analysis of outlier loci. The second row contains the loci names according to their primer combination and size in base pairs.
The list of outlier loci detected for each island (RAMSÖ, RAMSHOLMEN)in this study is available in the file LittorinaSaxatilis_AFLPs_list_outliers.txt.
The landmark data from the geometric morphometric analysis is available in the file LittorinaSaxatilis_LandmarkData.txt. The names of the INDIVIDUALS are the same as the names in the LittorinaSaxatilis_AFLPs.txt file.
We studied E (exposed) and S (sheltered) Littorina saxatilis ecotypes from 2 islands from shores of Sweden. In each island we sampled one transect along the L. saxatilis hybrid zone which contained two parental populations (2S, 2E) at +27m and -27m from the hybrid population, two populations (1S, 1E) at +9m and -9m from the hybrid population and one hybrid population (H).
LOCALITY: RAMSÖ, RAMSHOLMEN
ECOTYPE: E (exposed), S (sheltered), H (hybrid)
POPULATION: 2S, 1S, H, 1E, 2E
INDIVIDUAL: This is the individual code.
The sampling, AFLP analysis and genotyping have been performed by Johan Hollander (johan.hollander@biol.lu.se).
LittorinaSaxatilis_AFLPs_list_outliers
The list of outlier loci detected for each island (RAMSÖ, RAMSHOLMEN)in this study is available in the file LittorinaSaxatilis_AFLPs_list_outliers.txt.
LittorinaSaxatilis_LandmarkData
The landmark data from the geometric morphometric analysis is available in the file LittorinaSaxatilis_LandmarkData.txt. The names of the INDIVIDUALS are the same as the names in the LittorinaSaxatilis_AFLPs.txt file.
