Conservation and polymorphism of mitochondrial intergenic sequences in brown algae (Phaeophyceae)

Abstract

Due to their haploid nature, uniparental inheritance and apparent absence of recombination, organellar DNA markers are ideal tools for studying both intraspecific and interspecific phylogenies. Although 'universal' cytoplasmic DNA primers have become available for both red and green seaweeds, they are not transferable to brown seaweeds. Thus, based on the sequence of mitochondrial genome of the kelp Laminaria digitata, we developed universal-type primers for seven intergenic spacer loci and one mononucleotide tandem repeat locus. We investigated the conservation and sequence variation of these loci among nine Laminarialean and three fucoid species, as well as intraspecific polymorphism within five of these species. Six loci were conserved in at least four of the five brown algal families tested and five were polymorphic within at least one species. Although overall levels of divergence were relatively homogenous ( ¼ 0.314 AE 0.031), a hierarchical analysis suggests there is variation in the rate of evolutionary change among the six intergenic spacers. Due to their high degree of transferability, versatility and to non-coding nature, we argue that these intergenic spacer loci are highly efficient markers for within-family phylogenetic studies and for intra-specific phylogeographic studies in brown seaweeds.

Molecular evidence for the coexistence of two sibling species in Pylaiella littoralis (Ectocarpales, Phaeophyceae) along the Brittany coast

“…Our results confirm that chloroplastic markers have lower mutation rates than mitochondrial markers (e.g., for brown algae: Presting , Engel et al. , Tellier et al. ).…”

Phenological and molecular studies on the introduced seaweed Dictyota cyanoloma (Dictyotales, Phaeophyceae) along the Mediterranean coast of the Iberian Peninsula

“…In D. cyanoloma, we have observed the same amount of variability in rbcL-rbcS spacer as in cox1. The results confirm the potential usefulness of these mitochondrial and plastid regions at the intra-specific level in brown algae as previously suggested by Engel et al, (2008).…”

Phylogeography ofPadina boryana(Dictyotales, Phaeophyceae) around the Thai-Malay Peninsula

“…For example, mitochondrial DNA and plastid DNA have been used to study populations, and for phylogenetic reconstruction, in the Fucales (Coyer et al, 2006;Engel et al, 2008;Dixon et al, 2012) and Dictyotales (De Clerck et al, 2006; Tronholm et al, 2010;Ni-Ni-Win et al, 2011;Silberfeld et al, 2013). The nuclear ITS region is also widely used in plants (Feliner & Rosselló, 2007) and marine organisms (Williams et al, 2002;Toews & Brelsford, 2012) for evolutionary studies and unravelling historical species dispersal, and is also useful in macroalgae (Lee et al, 1998;Vidal et al, 2003;Wang et al, 2008;Draisma et al, 2012) due to higher PCR amplification success rates and higher intraspecific variation (Schoch et al, 2012).…”