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Genetic relationships among pumpkinseed (Lepomis gibbosus) ecomorphs in freshwater reservoirs of Portugal

Bhagat, Yakuta, Wilson, Chris C., Fox, Michael G., Ferreira, M. Teresa
Ecology of freshwater fish 2011 v.20 no.2 pp. 287-298
Lepomis gibbosus, freshwater, genetic relationships, genetic variation, habitats, microsatellite repeats, phenotypic plasticity, sympatry, Portugal
- High levels of morphological differentiation have been found among pumpkinseeds (Lepomis gibbosus) occupying four habitat types in Portuguese reservoirs. To investigate the underlying mechanism behind the phenotypic differentiation among ecomorphs, we used six microsatellite markers to assess patterns of genetic differentiation among and within eight naturalised reservoir populations. Greater genetic differentiation was seen among reservoir populations than within reservoirs (FST > 0.041, P < 0.002). structure analysis revealed the presence of two distinct genetic groups among the set of eight reservoir populations. However, an analysis of co-occurring forms that were identified a priori by their respective habitats was consistent with a single panmictic group, suggesting that morphological differentiation has arisen in sympatry (i.e., within a reservoir, postintroduction). The observed relationships within and among reservoir populations, combined with the timeframe of ecomorph divergence, suggest the strong likelihood of phenotypic plasticity as the underlying mechanism of diversification in the introduced pumpkinseed.