SEMINAR: Monday January 24 2000, 11:00 am
Lister Hill Center (NIH BLdg 38A), 8th floor conference room

Sean Turner, Ph.D., Department of Biology, Indiana University,
a visitor of the NCBI taxonomy group, will present a talk on the
molecular systematics of cyanobacteria. The abstract is appended
below.

Regards,

   Detlef Leipe
   NCBI taxonomy group


Sean Turner: 
"Molecular systematics of cyanobacteria: problems and solutions"

The systematics and taxonomy of cyanobacteria ("blue-green algae")
have been unusually problematic due in large part to differences in
methodologies between the Botanical Code, by which cyanobacteria have
traditionally been classied, and the Bacteriological Code, by which
some investigators argue they should be classified, as they are now
recognized to be true bacteria.  Over the past 20 years, efforts have
been made by proponents of each method to find common ground in order
to resolve differences between competing classification systems, and
significant progress has been made toward this end.  However, during
the same period methods of molecular phylogenetic sequence analysis
have also been applied to the problem, and while there is some
agreement between the results of these studies and the emergent system
based on more classical criteria, there are also areas of significant
disagreement pertaining to inferred evolutionary relationships among
cyanobacteria and their systematic classification.  Results of
phylogenetic sequence studies using ribosomal RNAs from cyanobacteria
and photosynthetic plastids will be presented along with a discussion
of potentially confounding phenomena that can result in misleading
inferences based on these analyses.  Methods to circumvent such
effects will discussed and the results of their application to the
sequence data will be presented.