Plasticity first: molecular signatures of a complex morphological trait in filamentous cyanobacteria.

摘要: Filamentous cyanobacteria that differentiate multiple cell types are considered the peak of prokaryotic complexity and their evolution has been studied in context multicellularity origins. Species form true-branching filaments exemplify most complex cyanobacteria. However, mechanisms underlying morphology remain poorly understood despite several investigations focused on identification novel genes or pathways. An alternative route for traits is based existing phenotypic plasticity. According to scenario – termed genetic assimilation fixation a phenotype precedes genotype. Here we show transcriptional regulatory elements constitutes major mechanism new traits. We found supplementation with sucrose reconstitutes ancestral branchless two Fischerella species compared transcription start sites (TSSs) between states. Our analysis uncovers orthologous TSSs whose level correlated phenotype. These encode components septosome elongasome (e.g., fraC mreB). The concept supplies tenable explanation but testing its feasibility hindered by inability recreate study present-day present approach examine data plasticity first provide evidence occurrence during colony results reveal via modification pre-existing genes. ‘plasticity-first’ hypothesis highlights importance regulation