Cyanobacterial community structure as seen from RNA polymerase gene sequence analysis.
PCR was used to amplify DNA-dependent RNA polymerase gene sequences specifically from the cyanobacterial population in a seawater sample from the Sargasso Sea. Sequencing and analysis of the cloned fragments suggest that the population in the sample consisted of two distinct clusters of Prochlorococcus-like cyanobacteria and four clusters of Synechococcus-like cyanobacteria. The diversity within these clusters was significantly different, however. Clones within each Synechococcus-like cluster were 99 to 100% identical, while each Prochlorococcus-like cluster was only 91% identical at the nucleotide level. One Prochlorococcus-like cluster was significantly more closely related to a Mediterranean Sea (surface) Prochlorococcus isolate than to the other cluster, showing the highly divergent nature of this group even in one sample. The approach described here can be used as a general method for examining cyanobacterial diversity, while an oligotrophic ocean ecosystem such as the Sargasso Sea may be an ideal model for examining diversity in relation to environmental parameters.
Palenik
B
B
Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla 92093-0202.
D001483:Base Sequence; D000458:Cyanobacteria / Q000145:classification / Q000201:enzymology* / Q000235:genetics*; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics*; D017753:Ecosystem; D005798:Genes, Bacterial; D014644:Genetic Variation; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012689:Sequence Homology, Nucleic Acid; D014871:Water Microbiology
D017931:DNA Primers; D004269:DNA, Bacterial; D012321:DNA-Directed RNA Polymerases