What an Intron May Tell: Several Sexual Biospecies Coexist in Meriderma spp. (Myxomycetes)

Speciation in progress? A phylogeographic study among populations of Hemitrichia serpula (Myxomycetes)

“…This can happen due to the capacity of myxomycete spores to disperse over long distances [38]. A similar case was pointed out in another phylogenetic study of the myxomycete genus Meriderma , where a single specimen showed incongruence between SSU and EF1A phylogroups [20]. As indicated by the geographic origin of ribotypes from different clades and by the results of a Mantel test, geographic separation within ribotypes of H .…”

“…Feng et al . [20] provide a discussion of the biospecies concept and possible reproductive modes in myxomycetes on the example of the genus Meriderma , where as well several reproductively isolated, putative biospecies were found with SSU and EF1A markers. In the case of this study, the reproductive isolation is additionally underpinned by the distribution of the two varieties among clades (var.…”

“…For a widely distributed morphospecies like H . serpula geographic restriction may potentially lead to speciation, if mutations in mating-type genes governing amoebal compatibility become widespread in a regional population and cut it off from gene flow (see discussion in [20]). Such mutations should facilitate genotypic divergence, but with Kamono et al .…”

“…Early studies on a few cultivable species, mostly of the Physarales, developed an alternative species concept based on groups of compatible strains (biospecies, [18]). The few morphospecies with numerous strains investigated often split into groups of strains (putative biospecies) that are incompatible with each other; in addition presumably asexual strains were found in culture [19], which casted doubts to which extent the morphospecies concept is able to mirror adequately speciation processes in myxomycetes [20–22]. Recent molecular studies, using mostly the first 600 bp of the ribosomal small subunit rRNA gene (SSU) which is a useful barcoding marker in many protistean lineages [23–24] revealed a high ribotype diversity for most investigated myxomycete morphospecies.…”

“…Studies employing multiple markers for Trichia varia [30] and Meriderma spp. (formerly Lamproderma atrosporum , [20]) revealed groups of ribotypes that seem to be reproductively isolated from each other, constituting putative biospecies. If these relationships are the rule, the number of nearly 1 000 species described worldwide at a morphospecies level [31] would inflate by a factor between 2 and 10 at the biospecies level.…”