Hi All A question from a non microbiologist. If a plasmid has neomycin selection why can't you use neomycin as the selection antibiotic? Everyone uses G418 (Geneticin). What is the basis for using G418 vs neo? Toxicity? Cost? some other reason that I'm just too dumb to figure out :-) Thanks Mark Dr Mark Watson B.Sc.(Hon) Ph.D. Details at http://www.cbsm.uwa.edu.au/sigfile.html