MEPS 544:131-142 (2016)  -  DOI: https://doi.org/10.3354/meps11607

Lack of fine-scale genetic structure and distant mating in natural populations of Fucus vesiculosus

Sara Teixeira1,*, Gareth A. Pearson1, Rui Candeias1, Céline Madeira1, Myriam Valero2, Ester A. Serrão1

1Centre of Marine Sciences (CCMAR), University of Algarve, Campus of Gambelas, 8005-139 Faro, Portugal
2CNRS, UPMC Sorbonne Université, PUCCh, UACH, UMI EBEA 3614, Evolutionary Biology and Ecology of Algae, Station Biologique de Roscoff, CS 90074, Place Georges Teissier 29688 Roscoff Cedex, France
*Corresponding author:

ABSTRACT: Fine-scale spatial genetic structure (SGS) within populations reflects the dispersal behaviour of genes and individuals. Here we studied very small-scale SGS and mating patterns in the brown seaweed Fucus vesiculosus, a dioecious marine broadcast spawner with immediate settlement upon gamete release, which is predicted to strongly restrict gene flow. We estimated SGS, inbreeding and kinship for adults and recruits from habitats with contrasting exposures and patchiness (open coast and estuarine ecosystems) using microsatellite loci. Heterozygote deficiency was found for most adult populations but it was even higher for recruits, indicating inbreeding depression. At the fine spatial resolution of this study there was no spatial genetic structuring for 3 of the 5 populations studied across different habitats. Habitat could not explain the unrestricted gene flow in some populations. In the kinship analyses, we identified more putative mothers than fathers, suggesting that male gamete dispersal mediates gene flow at broader distances. However, the vast majority of the parents of the recruits could not be found among the adults sampled nearby, indicating unrestricted gene flow at these small scales. We propose 3 non-exclusive hypotheses for our findings: (1) unrestricted gene flow, (2) inbreeding depression eliminating most inbred individuals resulting from nearby related parents, (3) temporal Wahlund effects, mediated by a hypothetic genetic pool of a bank of microscopic forms persisting from previous generations.


KEY WORDS: Brown algae · External fertilizer · Spatial genetic structure · Inbreeding · Microsatellite markers · Spatial autocorrelation


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Cite this article as: Teixeira S, Pearson GA, Candeias R, Madeira C, Valero M, Serrão EA (2016) Lack of fine-scale genetic structure and distant mating in natural populations of Fucus vesiculosus. Mar Ecol Prog Ser 544:131-142. https://doi.org/10.3354/meps11607

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