Objective   To establish a rolling circle amplification (RCA) method for detection of single base mutations of influenza A H1N1 resistance genes.    Methods   M2 and NA resistance gene of H1N1 were target gene in this research. Two circularizable probes (C-probe) were designed to detect these genes. C-probes were ligated to closed rings by DNA ligase when they specifically bond to target genes which had single base mutation. After the rolling circle amplification

the single base mutations were specifically detected. Optimal conditions for RCA method were studied

and the specificity and sensitivity of the method were determined by testing wild and mutation type artificial template. The specimens from clinic were detected and compared with sequencing method to confine its accuracy.    Results   Strict reaction conditions were needed for detection of single base mutation. Adopting heat cycle ligation and increasing the temperature (65 ℃) could make sure ligation fidelity. Through series detection of the target sequences with different concentrations

the lowest level of mutations detected by RCA was 1% of the total. RCA detection results were consistent with the sequencing method.    Conclusion   RCA technique is successfully used to detect single base mutation of influenza A H1N1 resistance genes.