Nucleic Acid Probes

In general, a nucleic acid probe is a single strand of either DNA or RNA that will hybridize, or bind, with its complementary sequences in the intended target nucleic acid. The use of nucleic acid probes in ecological and environmental analyses has several advantages over the more traditional biochemically based analyses. Selection of the specific segment of nucleic acid to be used as a gene probe is the most crucial part of the nucleic acid hybridization and depends upon the particular application. Many DNA fragments to be used as probes have been cloned into plasmid vectors, and the researcher should isolate the probe DNA from the vector prior to labeling. Nonradioactive probes are alternatives to radiolabeling for detection of nucleic acid sequences. Once target bacteria or DNA have been isolated from environmental samples, there are several ways in which nucleic acid probes can be used to identify specific sequences through DNA or RNA hybridization.