MULTIPLE CRYPTIC SPECIES: MOLECULAR DIVERSITY AND REPRODUCTIVE ISOLATION IN THE BOSTRYCHIA RADICANS/B. MORITZIANA COMPLEX (RHODOMELACEAE, RHODOPHYTA) WITH FOCUS ON NORTH AMERICAN ISOLATES

Abstract

Red algae of the Bostrychia radicans/B. moritziana complex are common in warm temperate areas of North America. Phylogenetic analysis of both plastid and mitochondrial DNA sequence data revealed seven distinct evolutionary lineages among worldwide samples. Although only two haplotypes (plastid and mitochondrial) were found in Pacific Mexico, four plastid and 11 mitochondrial haplotypes were found in a similar latitudinal spread along the Atlantic coast of the United States. On the U.S. Atlantic coast only one plastid haplotype was found in northern samples (Connecticut to North Carolina), whereas further south several plastid haplotypes were found. Phylogenetic analyses suggested that this single plastid haplotype found among northern samples could be the result of a northward range expansion possibly since the last glacial maximum. Crossing data of samples within the same evolutionary lineage showed that samples with the same plastid haplotypes were generally sexually compatible; samples with different plastid haplotypes were reproductively isolated. Samples from Pacific Mexico were partially reproductively compatible with some samples from the Atlantic USA (plastid haplotype C) and were more closely related to these samples than these U.S. samples were to other U.S. Atlantic samples. Compatible solute types mirrored the plastid haplotype, with plastid haplotype B having only sorbitol, whereas all other haplotypes also contained dulcitol. Samples from Atlantic USA, with different plastid haplotypes (e.g. B vs. C), but within the same evolutionary lineage, were reproductively isolated from each other. Data indicate that reproductive isolation occurs between and within supported evolutionary lineages and that the number of cryptic species is high.

A molecular re-examination of speciation in the intertidal red algaMastocarpus stellatus(Gigartinales, Rhodophyta) in Europe

“…2) may indicate changes in population size in the recent history of these reproductively isolated groups. This study again shows that even a few base-pair changes in the RuBisCo spacer may indicate genetic variation that is correlated with reproductively isolated groups, as is seen in Bostrychia Montagne (Zuccarello & West, 2003) and Porphyra C. Agardh (Brodie et al, 1996). Interestingly, the RuBisCo spacer sequence of a M. stellatus sample from Nova Scotia, Canada (Bird et al, 1994), shares a synapomorphy with the P1 haplotype.…”

Genetic diversity and molecular phylogeny of Planktothrix (Oscillatoriales, cyanobacteria) strains from China

“…Towards a refined view of the phylogenetic relationship and delimited species within the genus of Planktothrix, strains form other global regions (outside Europe), are needed for further examination. Additionally, it has been pointed out that morphological species delimitation tends to be problematic within the microalgae (cyanobacteria): many cases of cryptic species diversity are being disclosed through application of molecular phylogenetic methods (Kooistra, 2002;Zuccarello and West, 2003;Verbruggen et al, 2007). Therefore, we anticipated the present study following a molecular genetic approach will verify and elucidate whether cryptic species exist within species of the genus Planktothrix by using molecular genetic approaches.…”

Species boundaries and phylogenetic relationships within the green algal genus Codium (Bryopsidales) based on plastid DNA sequences

“…Famà et al, 2002;Kooistra, 2002;van der Strate et al, 2002;Zuccarello and West, 2003). As a consequence, pleas for molecular species delimitation are beginning to crop up in the phycological literature (Saunders and Lehmkuhl, 2005;Verbruggen et al, 2005a,b).…”