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Generation of Marked and Markerless Mutants in Model Cyanobacterial Species
Published on: May 29, 2016
Genome fluctuations in cyanobacteria reflect evolutionary, developmental and adaptive traits
John Larsson1, Johan Aa Nylander, Birgitta Bergman
1Department of Botany, Stockholm University, SE-106 09 Stockholm, Sweden. john.larsson@botan.su.se
BMC Evolutionary Biology
|July 2, 2011
Summary
Cyanobacteria exhibit diverse genome evolution strategies, with some expanding for adaptability and others streamlining for specific niches. Unique genes identified offer insights into specialized functions like symbiosis.
Area of Science:
- Microbiology
- Genomics
- Evolutionary Biology
Background:
- Cyanobacteria are ancient photosynthetic prokaryotes with diverse cellular differentiation, physiology, and habitats.
- Genomic analysis reveals significant variation in size and protein-coding capacity within the cyanobacterial phylum.
Purpose of the Study:
- To analyze the genomes of 58 cyanobacteria to understand genomic changes.
- To identify shared and unique orthologs across cyanobacterial lineages.
Main Methods:
- Comparative genomic analysis of 58 contemporary cyanobacterial genomes.
- Identification and characterization of orthologous gene families.
- Ancestral character reconstruction to infer ancestral genome size and gene content.
Main Results:
- Identified 404 core protein families conserved across all cyanobacteria, with two unique to the phylum.
- Cyanobacterial genome size evolution shows mixed gains/losses in complex clades and reduction in unicellular clades.
- Discovered unique orthologs associated with specific traits like filament formation and diazotrophy.
- Estimated the most recent common ancestor had a genome size of ~4.5 Mbp with 1678-3291 protein-coding genes.
Conclusions:
- Two distinct genome development routes: expansion for adaptive potential and streamlining for niche specialization.
- Extreme non-coding nucleotide proliferation suggests a transition from expansion to niche adaptation, leading to gene redundancy and loss.
- Specific orthologs correlate with phenotypes like filament formation and symbiotic competence, presenting targets for further research.
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