Data from: Intraspecific genetic admixture and the morphological diversification of an estuarine fish population complex

The North-east American Rainbow smelt (Osmerus mordax) is composed of two glacial races first identified through the spatial distribution of two distinct mtDNA lineages. Contemporary breeding populations of smelt in the St. Lawrence estuary comprise contrasting mixtures of both lineages, suggesting that the two races came into secondary contact in this estuary. The overall objective of this study was to assess the role of intraspecific genetic admixture in the morphological diversification of the estuarine rainbow smelt population complex. The morphology of mixed-ancestry populations varied as a function of the relative contribution of the two races to estuarine populations, supporting the hypothesis of genetic admixture. Populations comprising both ancestral mtDNA races did not exhibit intermediate morphologies relative to pure populations but rather exhibited many traits that exceeded the parental trait values, consistent with the hypothesis of transgressive segregation. Evidence for genetic admixture at the level of the nuclear gene pool, however, provided only partial support for this hypothesis. Variation at nuclear AFLP markers revealed clear evidence of the two corresponding mtDNA glacial races. The admixture of the two races at the nuclear level is only pronounced in mixed-ancestry populations dominated by one of the mtDNA lineages, the same populations showing the greatest degree of morphological diversification and population structure. In contrast, mixed-ancestry populations dominated by the alternate mtDNA lineage showed little evidence of introgression of the nuclear genome, little morphological diversification and little contemporary population genetic structure. These results only partially support the hypothesis of transgressive segregation and may be the result of the differential effects of natural selection acting on admixed genomes from different sources.Smelt AFLP data - Dodson et al. 2015 (PlosONE)This file contains AFLP genotypes (29 loci) for 447 Rainbow smelt (Osmerus mordax). One sheet contains the data, one sheet establishes the correspondence between Site numbers in the publication (Table 2 and Figure 2) and codes used for indiividual genotypes.DodsonAl_PlosONE15_AFLPdata.xlsxDodsonAl_PlosONE15_MorphoDataThis files contains morphological data. One sheet contains the data itself, one sheet establishes the correspondence between sampling sites in Figure 1 and Table 1 with the codes used in the datasheet; one sheet details the meaning of trait variables. These traits are also presented in the DodsonAl_PlosONE15_DescriptionVariables.pdf fil