To assess the reliability of DGGE,the V3 region fragments of prokaryotic 16S rDNA sequences were amplified by PCR and separated by DGGE with 40%—70% denaturing gradient in present study,and the differences of DNA sequences retrieved from DGGE bands were compared,and the concept of DGGE reliable index(RI) that was calculated by the equation RI =(Nss – Nsd + Ndd – Nds)/Ns,was introduced.The results showed that the probability of a single band retrieving similar sequences(the sequence diversity of the V3 regio...