Dataset Information

Intraspecific genetic admixture and the morphological diversification of an estuarine fish population complex.

ABSTRACT: 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.

SUBMITTER: Dodson JJ

PROVIDER: S-EPMC4391849 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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Intraspecific genetic admixture and the morphological diversification of an estuarine fish population complex.

Dodson Julian J JJ Bourret Audrey A Barrette Marie France MF Turgeon Julie J Daigle Gaétan G Legault Michel M Lecomte Frédéric F

PloS one 20150409 4

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 th ...[more]

PMID: 25856193

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Dataset Information

Intraspecific genetic admixture and the morphological diversification of an estuarine fish population complex.

Publications

Intraspecific genetic admixture and the morphological diversification of an estuarine fish population complex.

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