Milestones in DNA research The discovery of DNA structure in 1953 was the starting point of a real scientific and cultural revolution, the ending of which is difficult to predict. The discovery and use of enzymes that copy, cut and join DNA molecules in cells was the next step in this revolutionary course. The development of two major techniques contributed further to this already vertiginous process: the manual DNA sequencing method, which appeared in 1975, and the discovery of the polymerase chain reaction (PCR) in 1985, which allows the million-fold amplification of DNA sequences. A natural consequence of these two…