I have 3 neomycin/ kanamycin mutant strains of D. melanogaster ( homozygous) which show differences in fitness.The insert is approximately 790bp, cloned in on a bluescript phagemid. If anyone would like these strains or more information, please contact me by e.mail: CSB2CP at west-01.novell.leeds.ac.uk. Thanks, Catherine Poyser