Practical DNA technology in school .3. Mapping and methylation

Since the introduction of practical work in DNA technology to school science courses, there has been a need to expand on the limited set of available protocols to demonstrate further biological principles. The current paper sets out two additional practical exercises which can be used in schools. The first experiment involves restriction analysis of bacteriophage lambda DNA to map its cos sites, and in the second experiment the effect of methylation of lambda DNA on restriction enzyme digestion is examined. Based on practical exercises already widely available, these protocols extend analysis of actual molecular events and aid in their interpretation (Miller, 1993, 1994; Madden, 1993; Harrison, Sampson, and Harrison, 1992).