title: Decoding cyanobacterial phylogeny and molecular evolution using an evonumeric approach.
abstract: Forty-one heterocystous cyanobacteria strains representing 12 cyanobacterial genera collected from all across India were assessed in phylogenetic and evolutionary perspectives. The structural gene 16S ribosomal RNA (rRNA) and the functional genes nifD and psbA were selected as molecular chronometers in this study. The phylogenetic analyses demonstrated the monophyly of heterocystous cyanobacteria with significant intermixing, along with establishing the polyphyly of Stigonematales, strongly supporting the need for re-amendments in cyanobacterial taxonomy and systematics. Molecular trends obtained did not clearly reflect the phenotypic affiliations, thus advocating for genetic characterizations using more molecular markers. Large-scale evonumeric extrapolations of gene sequence data of all the three molecular markers was performed to assess the evolutionary pace of heterocystous cyanobacteria on the basis of nucleotide diversity, recombination frequencies, and the DNA divergence between the sampled taxa. The obtained results tilted the evolutionary pace in favor of the less complex Nostocales thus indicating that possibly the simple non-branched forms are more flexible and adaptive for evolutionary diversifications as compared to the more complex and branched ones. This study hence represents a unique blend of molecular phylogeny with evogenomic sequence analyses for understanding the genetic diversity, phylogeny, and evolutionary pace within the heterocystous cyanobacteria.
authors.affiliation: Laboratory of Microbial Genetics, Department of Botany, Banaras Hindu University, Varanasi, 221005, India.
authors.forename: Prashant
authors.initials: P
authors.lastname: Singh
authors.forename: Satya Shila
authors.initials: SS
authors.lastname: Singh
authors.forename: Marina
authors.initials: M
authors.lastname: Aboal
authors.forename: Arun Kumar
authors.initials: AK
authors.lastname: Mishra
mesh_terms: D000458:Cyanobacteria / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D019143:Evolution, Molecular; D005798:Genes, Bacterial; D014644:Genetic Variation; D058889:Molecular Typing; D045332:Photosystem II Protein Complex / Q000235:genetics; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D045332:Photosystem II Protein Complex; D012336:RNA, Ribosomal, 16S; C422369:photosystem II, psbA subunit