and for this purpose the cloning approach is not well suited, simply because it is too laborious, time consuming, and expensive.Hybridization techniques using specific oligonucleotide probes are more appropriate for studying population dynamics, but probes rely on sequence data and are either too specific, targeting only one particular population. or too general, overlooking closely related hut ecologically different populations. So to determine the diversity of different microorganisms in natural ecosystems, and to monitor microbial community behavior over time, other approaches are needed. One such approach is genetic fingerprinting of complex microbial communities.