Browsing by Author "Daguin, C."
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- Genetic entities and mating system in hermaphroditic Fucus spiralis and its close dioecious relative F. vesiculosus (Fucaceae, Phaeophyceae)Publication . Engel, C. R.; Daguin, C.; Serrão, EsterTo date, molecular markers have not settled the question of the specific status of the closely related, but phylogenetically unresolved, brown seaweeds, hermaphroditic Fucus spiralis and dioecious Fucus vesiculosus , nor their propensity for natural hybridization.
- Genetic isolation between three closely related taxa: fucus vesiculosus, F. spiralis, and F. ceranoides (Phaophyceae)Publication . Billard, E.; Daguin, C.; Pearson, G. A.; Serrão, Ester; Engel, C. R.; Valero, MyriamAll traditional markers, both phenotypic and phylogenetic, have failed to discriminate between the taxa composing the Fucus vesiculosus L., F. spiralis L., and F. ceranoides L. species complex, particularly in Brittany (France), so we used five microsatellite markers to compare the allelic frequencies of populations of the three taxa in this region. The aim of this study was to assess whether the different populations were grouped according to their geographical location, their habitat (open coast versus estuary), or their a priori taxonomic assignment. Species-specific alleles were identified at one locus, demonstrating the utility of microsatellite markers for recognizing the three taxa in Brittany. Moreover, our results clearly support the separation of F. vesiculosus, F. spiralis, and F. ceranoides into distinct species, independently of geography. We also identified genetic differentiation between estuarine and coastal populations of F. vesiculosus.
- Implications of mating system for genetic diversity of sister algal species: Fucus spiralis and Fucus vesiculosus (Heterokontophyta, Phaeophyceae)Publication . Perrin, C.; Daguin, C.; Van De Vliet, M. S.; Engel, C. R.; Pearson, G. A.; Serrão, EsterThe implications of mating system for genetic diversity were assessed in the sister species Fucus spiralis and Fucus vesiculosus using a combination of ten microsatellite markers. Five new microsatellite markers specific for F. spiralis were developed in order to increase marker resolution and complement the results (i.e. mating system and genetic diversity extended to a larger geographic scale) acquired using five microsatellite loci previously developed from a mixed fucoid seaweed DNA library that excluded F. spiralis. Low genetic diversities observed at the population and species level in F. spiralis using the five new F. spiralis-specific loci described here were consistent with the results obtained previously with non-specific microsatellite loci. Results revealed that selfing is characteristic in F. spiralis across its latitudinal distribution along the Iberian and French Atlantic coasts. Higher levels of within-population genetic diversity were observed in the outcrossing species F. vesiculosus, decreasing towards the southern distributional range of the species. Some cases of significant biparental inbreeding in this species are indicative of short gamete dispersal or mating of spatially or temporally structured populations. In contrast to within-population diversities, higher total genetic diversity among populations was observed in the hermaphroditic species in comparison to the dioecious F. vesiculosus.
- When is a hybrid a hybrid? A counter-reply to Wallace et al.Publication . Engel, C. R.; Daguin, C.; Serrão, EsterIn a reply to a brief citation of their paper (Wallace et al . 2004), Wallace et al . (2006) re-analyse their data using the same methods as we did (Engel et al . 2005) to conclude again that an ecad of the brown alga Fucus sp., which occurs only in a particular type of habitat, was a hybrid. While we wholly agree that the ecad individuals (called ‘muscoides-like’) may be putative hybrids, their conclusions were — and remain — confounded with other, alternative explanations. Here, in response to their Reply (Wallace et al . 2006), we wish to clarify our reservations more fully and offer some reflections on identifying hybrids in species complexes.