Decadal stability in genetic variation and structure in the intertidal seaweed Fucus serratus (Heterokontophyta: Fucaceae)

• Published in: BMC Evolutionary Biology
• Main Authors: Alexander Jueterbock, James A. Coyer, Jeanine L. Olsen, Galice Hoarau
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2018
• Subjects: Brown algae; Effective population size; Evolutionary potential; Genetic diversity; Microsatellites; North Atlantic; Evolution; QH359-425
• Online Access: https://doi.org/10.1186/s12862-018-1213-2; https://doaj.org/article/85e8824ff37f409dbc6029090b147c5a

Abstract Background The spatial distribution of genetic diversity and structure has important implications for conservation as it reveals a species’ strong and weak points with regard to stability and evolutionary capacity. Temporal genetic stability is rarely tested in marine species other than commercially important fishes, but is crucial for the utility of temporal snapshots in conservation management. High and stable diversity can help to mitigate the predicted northward range shift of seaweeds under the impact of climate change. Given the key ecological role of fucoid seaweeds along rocky shores, the positive effect of genetic diversity may reach beyond the species level to stabilize the entire intertidal ecosystem along the temperate North Atlantic. In this study, we estimated the effective population size, as well as temporal changes in genetic structure and diversity of the seaweed F. serratus using 22 microsatellite markers. Samples were taken across latitudes and a range of temperature regimes at seven locations with decadal sampling (2000 and 2010). Results Across latitudes, genetic structure and diversity remained stable over 5–10 generations. Stable small-scale structure enhanced regional diversity throughout the species’ range. In accordance with its biogeographic history, effective population size and diversity peaked in the species’ mid-range in Brittany (France), and declined towards its leading and trailing edge to the north and south. At the species’ southern edge, multi-locus-heterozygosity displayed a strong decline from 1999 to 2010. Conclusion Temporally stable genetic structure over small spatial scales is a potential driver for local adaptation and species radiation in the genus Fucus. Survival and adaptation of the low-diversity leading edge of F. serratus may be enhanced by regional gene flow and ‘surfing’ of favorable mutations or impaired by the accumulation of deleterious mutations. Our results have clear implications for the conservation of F. serratus at its genetically unique ...