A half DNA ladder is a template for copying the whole. Matthew Meselson was born in Denver, Colorado. He had always wanted to be a chemist and chemical warfare thesis a huge lab workshop set up in his family’s basement and garage.
In 1954, Meselson went to Woods Hole to be a teaching assistant. Here, Meselson met Franklin Stahl — a post-doctoral fellow who was taking courses to learn some molecular biology techniques. Meselson and Stahl had a profitable summer during which they discussed theory and possible experiments. They were especially interested in trying to devise a way to prove or disprove Watson and Crick’s model of semi-conservative replication. Meselson and Stahl found themselves so in tune with each other’s ideas that they agreed to work together on devising the right experiment. In 1957, while doing the experiments with Stahl, Meselson gathered enough data to finish his Ph. He then stayed at Caltech, first as a research fellow and then as an assistant professor of chemistry.
Meselson worked on phage recombination — showing that recombination results from the splicing of DNA molecules. In 1960, François Jacob and Sydney Brenner came to his lab at Caltech where they obtained the data necessary to prove the existence of mRNA. In the fall of 1960, Meselson accepted the position of associate professor of molecular biology at Harvard University, where he is currently the Thomas Dudley Cabot Professor of the Natural Sciences. He discovered the enzymatic basis of host DNA protection, where the cell recognizes its own DNA by adding methyl groups to it. Foreign DNA will be attacked and destroyed by restriction enzymes but host, methylated, DNA remains intact.
Since 1963, Meselson has been concerned about the use of chemical and biological weapons in warfare. He has acted as a consultant for a number of government agencies, and participated in scientific studies that studied the effects of accidental and misuse of biological weapons. Matthew Meselson was one of the scientists who investigated the use of biological agents in Vietnam. The samples turned out to be bee pollen. Initially, Meselson and Stahl used phage DNA in their density gradient experiments. Phage DNA did not band well in the centrifuge tubes and gave uninterpretable results. Funded by The Josiah Macy, Jr.