Insights into Cyanobacterial Evolution from Comparative Genomics
Wesley D. Swingley, Robert E. Blankenship and Jason Raymond
from: The Cyanobacteria: Molecular Biology, Genomics and Evolution (Edited by: Antonia Herrero and Enrique Flores). Caister Academic Press, U.K. (2008)
Recent high-throughput sequencing has provided DNA sequences at an unprecedented rate, posing considerable analytical challenges, but also offering insight into the genetic mechanisms of adaptation. Here we present a comparative genomics-based approach towards understanding the evolution of these mechanisms in cyanobacteria. Historically, systematic methods of defining morphological traits in cyanobacteria have posed a major barrier in reconstructing their true evolutionary history. The advent of protein, then DNA, sequencing - most notably the use of 16S rRNA as a molecular marker - helped circumvent this barrier and now forms the basis of our understanding of the history of life on Earth. However, these tools have proved insufficient for resolving relationships between closely related cyanobacterial species. The 24 cyanobacteria whose genomes are compared here occupy a wide variety of environmental niches and play major roles in global carbon and nitrogen cycles. By integrating phylogenetic data inferred for hundreds to nearly 1000 protein coding genes common to all or most cyanobacteria, we are able to reconstruct an evolutionary history of the entire phylum, establishing a framework for resolving how their metabolic and phenotypic diversity came about read more ...