Metode for stabil merking av mikroorganismer

摘要

A method of selectively monitoring development and/or competitiveness of a microbial strain in a sample environment, comprising inserting a selectively detectable genetic label into the strain and adding the labelled strain to the sample environment and isolating DNA or RNA of said strain from the sample environment and detecting the amount of the genetic label. The method is also used for selecting, among a multiplicity of microbial strains, the strain that in a pre-selected environment and under pre-selected conditions has the highest capability to survive, multiply and/or express a pre-selected gene. The amount of genetic label is detected by PCR including a PCR technique that is capable of detecting a label consisting of a single nucleotide substitution, including a technique where the first PCR cycle involves the use of a reverse transcriptase. The method is also useful for establishing the identity and origin of a microbial strain by inserting a genetic label comprising a coded message.