Milestones timeline : Nature Milestones in DNAMilestones timeline PDF of Milestones timeline (82 KB)PDF of all Milestones (1,560 KB) 1952 Electrophoresis (Milestone 1) 1967 Discovery of DNA ligase (Milestone 2) 1969 FISH (Milestone 3) 1970 Discovery of restriction enzymes (Milestone 4) Discovery of reverse transcriptase (Milestone 5) 1972 Cloning (Milestone 2) 1975 Southern blot (Milestone 6) 1977 1937 DNA sequencing (Milestone 7) 1980 RFLP c
