Petr Dvorak | Species and speciation in cyanobacteria скачать в хорошем качестве

Petr Dvorak | Species and speciation in cyanobacteria

Petr Dvorak - Palacky University Olomouc, Czech Republic Twitter:   / dvorikus   Research Gate: https://www.researchgate.net/profile/... Species and speciation in cyanobacteria Cyanobacteria have evolved over three billion years and they conquered all environments with sufficient light intensity. We recognize thousands of species. However, the drivers of the species divergence are still poorly understood as in the rest of prokaryotes. Morphological features suggested that cyanobacteria evolved into coherent and highly diversified groups (genera like Synechococcus, Leptolyngbya, and Phormidium). However, a growing number of phylogenetic trees based on 16S rRNA or whole genome sequences showed that most of the traditional cyanobacterial genera are polyphyletic. For example, Synechococcus diverged into 12 polyphyletic lineages. It led to the boom of new genera in the last decade because each polyphyletic lineage can be recognized as a new genus. This pattern can be explained by the dynamic nature of speciation. We focused on speciation within cosmopolitan soil cyanobacterium Microcoleus vaginatus. The 16S rRNA and ITS phylogeny of ~500 strains (from all continents except for South America) revealed that this species is composed of 13 lineages – putative species. The diversification was driven by both isolation by distance and climate. Phylogenomic inference showed that these lineages are entangled by gene flow and they diverged in Pliocene. None of the putative species appeared to fully diverge – they are incipient species. Cyanobacterial species are the most frequently erected based on the monophyletic species concept. However, this concept (and all other concepts) consider a species as a discrete unit. We offer a probabilistic solution to the species problem (universal probabilistic concept of evolutionary lineages), which reflects the dynamics and incomplete divergence of the species. It can be applied to all domains of life because most of the lineages seem to be maintained by the gene flow. This talk is part of the CyanoWorld online seminar series, hosted by Nicolas Schmelling and Ilka Axmann, and was held on Zoom on November 11th, 2021. Follow Us on Twitter:   / cyanoworld1