their relative avidities for different variants are different for example a first probe may bind strongly to a wild type sequence moderately to a first allele weakly to a second allele and not at all to a third allele while a second probe may bind weakly to the wild type sequence and the first variant and moderately to the second variant and the third variant additional sloppy probes will exhibit yet different binding patterns due to their different target binding sequences thus fluorescence emission spectra from combinations of sloppy probes define different microbial strains or species as well as allelic variants of genes in mammalian tissues that are associated with diseases and somatic mutations assays according to this invention are described below utilizing our most preferred sloppy probes namely u201c sloppy molecular beacon probes u201d because sloppy probes reproducibly fluoresce with variable intensities after binding to different dna sequences combinations can be used in for example simple rapid and sensitive nucleic acid amplification reaction assays e g pcr based assays that identify multiple pathogens in a single reaction well it is understood however that the assays can be performed also on samples suspected of containing directly detectable amounts of unamplified target nucleic acids this novel species identification assay is based on deconvolving the spectra of a set of partially hybridizing sloppy signaling probes such as.