|Matthew S. Meselson|
24 May 1930 |
Denver, Colorado, USA
|Fields||Genetics, Molecular Biology|
|Alma mater||University of Chicago
California Institute of Technology
|Doctoral advisor||Linus Pauling|
|Doctoral students||Susan Lindquist|
Matthew Stanley Meselson (born May 24, 1930) is an American geneticist and molecular biologist whose research was important in showing how DNA replicates, recombines and is repaired in cells. In his mature years, he has been an active chemical and biological weapons activist and consultant. He is married to the medical anthropologist and biological weapons writer Jeanne Guillemin.
Youth and education
Meselson studied chemistry at the University of Chicago and graduated in 1951. He went on to study under Linus Pauling who assigned him work on x-ray crystallography which he later wrote a thesis on in 1958. He was a research fellow and then Assistant Professor of Physical Chemistry at Caltech until he joined the Harvard faculty in 1960, where he conducts research in molecular genetics and evolution. He started in Harvard as associate professor and taught undergraduate genetics for many years.
In 1957 with Franklin Stahl he showed that DNA replicates semi-conservatively. The Meselson-Stahl experiment used the Escherichia coli grown in the presence of the nitrogen isotope nitrogen-15, which was then switched to be grown with normal nitrogen, nitrogen-14. When they extracted the DNA using density centrifugation they found three types of DNA, one containing nitrogen-15, one containing nitrogen-14, and a hybrid containing both isotopes. When the hybrid DNA was made single stranded by heating, they could show one parental strand and one that had been newly synthesized, so when DNA is synthesized the DNA double helix splits into two, each of the single strands acting as a template for the synthesis of a complementary strand. This phenomenon is called semi-conservative DNA replication.
He showed in the years that followed many more theories in relation to this with the help of Jean Weigle. In 1961 with Sydney Brenner and François Jacob he later demonstrated that ribosomal RNA molecules are stable, which later proved the existence of mRNA - a problem scientists had struggled with previously. He later showed with Charles Radding that genetic recombination results from the splicing of DNA molecules. He also demonstrated the enzymatic basis of a process by which cells recognize and destroy foreign DNA, and discovered methyl-directed mismatch repair, which enables cells to repair mistakes in DNA.
The Meselson effect
The Meselson laboratory studies the evolution of asexuality in bdelloid rotifers. Meselson described the "Meselson effect", in which two alleles in an asexual organism evolve independently and divergently over time, producing what is essentially two genomes in one organism. This is due to the lack of sexual recombination which would have shuffled alleles between chromosomes during meiosis. Meselson's laboratory provided evidence that this is indeed the case in asexual bdelloid rotifers, and the Meselson effect was subsequently used to explain how bdelloid rotifers deal with dehydration. Dr. Alan Tunnacliffe's Cambridge lab showed that the lea gene had diverged through the Meselson effect into two different genes whose protein products work in synergy to preserve the organism during periods of dehydration, suggesting that the Meselson effect may only occur at loci where selection prevents LOH.
Work in other Daphnia pulex indicates that asexual genomes tend to lose heterozygousity over time because of frequent gene conversion events, producing an anti-Meselson effect. In Bdelloid rotifers allelic divergence occurs at some loci but not others, and does not occur in genome-wide fashion.
Chemical and biological weapons disarmament activism
In 1963 Meselson served as a resident consultant in the US Arms Control and Disarmament Agency, since then he has been involved in chemical and biological weapons disarmament policy formation as a consultant and through the Harvard Sussex Program, a disarmament think-tank.
- Meselson was a leader in a 1980s effort investigating allegations made by the CIA and the US State Department that "yellow rain" was a Soviet biological warfare agent. Meselson was among several scientists whose work concluded that the purported agent was bee droppings.
- In 1992–94, Meselson investigated and reported on the Sverdlovsk anthrax leak, a 1979 bio-warfare mishap in the Soviet Union that resulted in the deaths of 64 persons. Despite initially voicing support for the official Soviet story that the deaths were the unintentional result of ingestion anthrax from naturally infected cattle, Meselson was eventually forced to concede that the deaths were actually inhalation anthrax and did, in fact, come from the Sverdlovsk anthrax production plant, which existed in direct violation of the Biological Weapons Convention.
- 1975 Caltech Distinguished Alumni Award.
- 1984 MacArthur Fellows Program Genius Award.
- 1995 Genetics Society of America - Thomas Hunt Morgan Medal for lifetime contributions.
- 2002 American Society for Cell Biology’s Public Service Award for Advancing Prevention of Chemical and Biological Weapons.
- 2004 Lasker Award for Special Achievement in Medical Science. The prize honors a lifetime of solving fundamental biological problems.
- 2005 Election as Honorary Life Member to the National Academy of Sciences.
- 2008 Mendel Medal of the UK Genetics Society.
- Gitschier, J. (2011). "A Flurry of Folding Problems: An Interview with Susan Lindquist". PLoS Genetics 7 (5): e1002076. doi:10.1371/journal.pgen.1002076. PMC 3093363. PMID 21589898.
- Butlin, R. (2002). "OPINION — EVOLUTION OF SEXThe costs and benefits of sex: New insights from old asexual lineages". Nature Reviews Genetics 3 (4): 311–317. doi:10.1038/nrg749. PMID 11967555.
- Pouchkina-Stantcheva, N. N.; McGee, B. M.; Boschetti, C.; Tolleter, D.; Chakrabortee, S.; Popova, A. V.; Meersman, F.; Macherel, D.; Hincha, D. K.; Tunnacliffe, A. (2007). "Functional Divergence of Former Alleles in an Ancient Asexual Invertebrate". Science 318 (5848): 268–271. doi:10.1126/science.1144363. PMID 17932297.
- Tucker AE, Ackerman MA, Eads BD, Xu S, Lynch M. (2013) Population-genomic insights into the evolutionary origin and fate of obligately asexual Daphnia pulex. PNAS. 110:15740.
- Flot J-F, Hespeels B, Li X, Noel B, Arkhipova I, Danchin EGJ, Hejnol A, Henrissat B, Koszul R, Aury JM, Barbe V, Barthélémy RM, et al. (2013) Population-genomic insights into the evolutionary origin and fate of obligately asexual Daphnia pulex. PNAS. 110:15740.
- Yellow rain: Thai bees' faeces found doi:10.1038/308485b0 PMID 6709055
- Yellow rain evidence slowly whittled away doi:10.1126/science.3715471 PMID 3715471
- Matthew Meselson
- Matthew Meselson's short talk: The Semi-Conservative Replication of DNA
- Matthew Meselson's bio at Harvard Kennedy School
- The Meselson Laboratory
- The Meselson - Stahl Experiment
- Video of a talk by Meselson titled "Linus Pauling as an Educator"