Evolution is a basic, biological process

Shucks, that's nothin' ... hot threads can get that many posts in a very few days.Welcome to EvC!

And, although the change that confers resistance in any particular experiment often differs (that's the way evolution works), in many cases we can identify the change and show that it was not present in the original bacterium is present in the final population. For example, in many experiments resistance to streptomycin is conferred by a single point mutation in the rpsL gene, coding for a particular ribosomal protein (S12). "AAA" in codon 42 mutates to either "ACA" or "AGA" and the bacterium laughs at streptomycin. See, for example, Novel ribosomal mutations affecting translational accuracy, antibiotic resistance and virulence of Salmonella typhimurium.

Sorry, wrong. The mutation event is proven. In many of the experiments, literally thousands of them, the fact that a random mutation conferred the antibiotic resistance is a result of measurements, not assumptions. A little simplistically put you start with one bacterium, sequence its genome, grow a culture from it, introduce the antibiotic, grow the survivors, re-introduce the antibiotic, and repeat until you have a mostly resistant population. Then sequence the genome of a few of the resistant populaation, compare it to the original, note the differences, then run other tests to determine what the differences do.See, for example, the link I posted in my message just above this one. {edited to add: see also Acquisition of Certain Streptomycin-Resistant (str) Mutations Enhances Antibiotic Production in Bacteria.}Evolution is not assumed, it is measured.This message has been edited by JonF, 01-11-2005 20:45 AM

AFAIK they aren't abreviations, although they may be. I think they're just names.