Detection by RAPD of genetic alterations in vitro:: Amplification and conservation conditions of DNA extracts

The technique of randomamplified polymorphic DNA (RAPD) permits the study of genetic ecotoxicology without having to face the problem posed by the high number of chromosomes generally presented by the fish species used in traditional methods. Additionally, the use of in vitro systems allows the study of a large number of samples in environmental-risk assessment. Good standardization of the parameters involved in the RAPD reaction, such as primer concentration and the DNA template used and its integrity, is fundamental for obtaining reliable and repeatable results. This is especially important when the differences in DNA fingerprints between control cells and cells exposed to genotoxic agents are interpreted as toxic-dependent alterations. The use of more than one primer increases sensitivity in the detection of such differences, provided the amplification is carried out under optimum conditions. This article demonstrates that the conditions established for certain primers in previous studies can be acceptable for others, independent of the complexity of band patterns generated. Furthermore, the integrity of the DNA is shown to be stable for several months in the genomic extracts stored at 4degrees C, which to a large extent facilitates the application of this methodology.