1) Polymerase chain reaction (PCR) is an essential technique in molecular biology. It is the technique that gave us the human genome project and is a key aprt of virtually every major genetic discovery for the last 20 years. Its beginnings, however, are much more humble: PCR depends on the use of thermostable polymerases to amplify DNA strands. This brings us to 1965, when Thomas Brock was studying Thermus acquaticus bacteria from hydrothermal vents. From these, he isolated Taq polymerase. At the time, nobody had any clue that hydrophilic bacteria were of national interest.
2) The discovery of green fluorescent protein, one of the most widely used tools in molecular biology. From wikipedia: "In the 1960s and 1970s, GFP, along with the separate luminescent protein aequorin, was first purified from Aequorea victoria and its properties studied by Osamu Shimomura. . . However, its utility as a tool for molecular biologists did not begin to be realized until 1992 when Douglas Prasher reported the cloning and nucleotide sequence of wtGFP in Gene. The funding for this project had run out, so Prasher sent cDNA samples to several labs. The lab of Martin Chalfie expressed the coding sequence of wtGFP, with the first few amino acids deleted, in heterologous cells of E. coli and C. elegans, publishing the results in Science in 1994."