In article <5bfqeg$555 at mserv1.dl.ac.uk>, "g.clark" <g.clark at lshtm.ac.uk> wrote:
>>>Perhaps the 'rules' are different for bacteria but I do not think species
>>>should be described on the basis of rDNA alone. In eukaryotes there are
>>>examples of bona fide biological species (i.e. unable to interbreed) of
>>>the ciliate Tetrahymena that have identical small subunit ribosomal RNA
>>>sequences. Therefore identical sequence does not mean same species.
>>>>>>IMHO you need more than just sequence variation to warrant the
>>>recognition of a new species. But perhaps bacteriologists feel differently.
Thanks for your comments....I am indeed interested in BACTERIA.
My impression of the situation with bacteria is that the 16S rRNA
sequence is the "GOLD STANDARD" for designating (or identifying) a
bacterium at the species level. I'm just not sure how much of the
16S rRNA sequence one needs to be able to accomplish this task (as I
queried in my original posting).