Abstract:Background: Theory predicts that speciation can be quite rapid. Previous examples comprise a wide range of organisms such as sockeye salmon, polyploid hybrid plants, fruit flies and cichlid fishes. However, few studies have shown natural examples of rapid evolution giving rise to new species in marine environments.
“…It is now widely accepted that species in the Fucus genus experienced recent radiation (Leclerc et al 1998, Serrão et al 1999, Coyer et al 2006. In recent studies, authors have tried to date these splitting events; by inferring a molecular clock, Hoarau et al (2007) recently suggested a divergence time of 10 to 16 million yr between Fucus and Ascophyllum nodosum and of 2.3 to 5.5 million yr within Fucus and Muhlin & Brawley (2009), using the same molecular clock, dated the divergence between haplotypes of F. vesiculosus between 35 000 and 65 000 yr ago, while with microsatellites, Pereyra et al (2009) estimated the time since divergence of F. radicans and F. vesiculosus around 400 yr ago (125 to 2475 yr ago) using a coalescent approach. As mentioned by Coyer et al (2006) it is not trivial to find a consensus for the species concept within the Fucus genus because of intraspecific morphological variation and frequent hybridization among taxa.…”
Intertidal rocky shores provide classic examples of habitat-driven divergent selection. We show that the species complex Fucus vesiculosus L./F. spiralis L. is composed of 3 distinct genetic entities that have evolved along different time scales. Using assignment tests based on microsatellite markers and performed on randomly sampled individuals in 2 separate geographic regions (Portugal and France), we reveal that F. spiralis consists of 2 genetic entities that have distinct vertical distributional patterns along the intertidal gradient of selective pressures. Individuals assigned to the cluster found higher on the shore are also morphologically different. They are smaller and bushy, with dichotomous ramifications and no sterile rime around receptacles. Patterns of genetic divergence suggest different times and pathways to reproductive isolation. Divergence between F. vesiculosus and the F. spiralis complex seems to have occurred first, coinciding with divergence in reproductive mode; dioecy versus selfing hermaphroditism. Later, in the hermaphroditic lineage, parallel evolution of 2 co-occurring genetic clusters may have been driven by natural selection and facilitated by high selfing rates in the F. spiralis complex.
“…It is now widely accepted that species in the Fucus genus experienced recent radiation (Leclerc et al 1998, Serrão et al 1999, Coyer et al 2006. In recent studies, authors have tried to date these splitting events; by inferring a molecular clock, Hoarau et al (2007) recently suggested a divergence time of 10 to 16 million yr between Fucus and Ascophyllum nodosum and of 2.3 to 5.5 million yr within Fucus and Muhlin & Brawley (2009), using the same molecular clock, dated the divergence between haplotypes of F. vesiculosus between 35 000 and 65 000 yr ago, while with microsatellites, Pereyra et al (2009) estimated the time since divergence of F. radicans and F. vesiculosus around 400 yr ago (125 to 2475 yr ago) using a coalescent approach. As mentioned by Coyer et al (2006) it is not trivial to find a consensus for the species concept within the Fucus genus because of intraspecific morphological variation and frequent hybridization among taxa.…”
Intertidal rocky shores provide classic examples of habitat-driven divergent selection. We show that the species complex Fucus vesiculosus L./F. spiralis L. is composed of 3 distinct genetic entities that have evolved along different time scales. Using assignment tests based on microsatellite markers and performed on randomly sampled individuals in 2 separate geographic regions (Portugal and France), we reveal that F. spiralis consists of 2 genetic entities that have distinct vertical distributional patterns along the intertidal gradient of selective pressures. Individuals assigned to the cluster found higher on the shore are also morphologically different. They are smaller and bushy, with dichotomous ramifications and no sterile rime around receptacles. Patterns of genetic divergence suggest different times and pathways to reproductive isolation. Divergence between F. vesiculosus and the F. spiralis complex seems to have occurred first, coinciding with divergence in reproductive mode; dioecy versus selfing hermaphroditism. Later, in the hermaphroditic lineage, parallel evolution of 2 co-occurring genetic clusters may have been driven by natural selection and facilitated by high selfing rates in the F. spiralis complex.
“…Notably, a number of species have thus been able to evolve local adaptations over only a few thousand years, and in one exceptional case, the rapid evolution has even resulted in the formation of a new and endemic species, F. radicans. This species originates from Baltic Sea populations of F. vesiculosus and was formed no more than a few thousand years ago (Pereyra et al 2009). …”
Section: Rapid Evolution Of Baltic Sea Populationsmentioning
confidence: 99%
“…Phenotypic plasticity allows populations to adjust within the time-scale of a generation to a minor environmental change, while the presence of genetic variation constitutes the basis for evolutionary changes resulting in differentiation among populations after a minimum of some generations. In some cases evolutionary change may even result in formation of new species, and a pertinent example of this in the Baltic Sea is the new species Fucus radicans formed within the last few thousands of years (Pereyra et al 2009). …”
Environmental change challenges local and global survival of populations and species. In a speciespoor environment like the Baltic Sea this is particularly critical as major ecosystem functions may be upheld by single species. A complex interplay between demographic and genetic characteristics of species and populations determines risks of local extinction, chances of re-establishment of lost populations, and tolerance to environmental changes by evolution of new adaptations. Recent studies show that Baltic populations of dominant marine species are locally adapted, have lost genetic variation and are relatively isolated. In addition, some have evolved unusually high degrees of clonality and others are representatives of endemic (unique) evolutionary lineages. We here suggest that a consequence of local adaptation, isolation and genetic endemism is an increased risk of failure in restoring extinct Baltic populations. Additionally, restricted availability of genetic variation owing to lost variation and isolation may negatively impact the potential for evolutionary rescue following environmental change.
“…The dynamic radiation, which continues in contemporary time as evidenced by the speciation of Fucus radicans in the upper Baltic Sea within the past 2000-400 yrs (Pereyra et al, 2009), has long challenged our concepts of species and speciation, largely because of environmentally-determined morphologies and extensive hybridization among the component entities.…”
Section: Introductionmentioning
confidence: 99%
“…Habitat-driven speciation has also occurred in subtidal F. vesiculosus/F. radicans (Bergström et al, 2005;Pereyra et al, 2009).…”
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.