(Montana State University - Bozeman, College of Agriculture, 2004) Allewalt, Jessica Post; Chairperson, Graduate Committee: David M. Ward.
Previous molecular analysis of a well-studied microbial mat system in Yellowstone National Park revealed numerous genetically distinct 16S rRNA sequences distantly related to the 16S rRNA sequence of the unicellular cyanobacterium Synechococcus lividus. These new genotypes were shown to be contributed by the predominant cyanobacterial populations. Patterns in genotype distribution relative to temperature and light conditions suggested that these populations may have evolved through adaptive radiation to fill ecological niches. In order to test this hypothesis, Synechococcus isolates were cultivated using a dilution and filtration approach, then shown to be genetically relevant compared to natural mat populations by similarities of 16S rRNA genes and the 16S-23S intervening transcribed spacer (ITS) regions. Several isolates were retrieved that were identical or closely related to predominant mat genotypes at both loci. Other Synechococcus isolates were relevant at the 16S rRNA locus, but had ITS sequences not yet found in the mat.
