Matthew S. Meselson in 1964

Matthew Stanley Meselson (b. 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. is the 144th day of the year (145th in leap years) in the Gregorian calendar. ... Year 1930 (MCMXXX) was a common year starting on Wednesday (link will display 1930 calendar) of the Gregorian calendar. ... A geneticist is a scientist who studies genetics, the science of heredity and variation of organisms. ... DNA replication. ... Recombination usually refers to the biological process of genetic recombination and meiosis, a genetic event that occurs during the formation of sperm and egg cells. ... DNA damage resulting in multiple broken chromosomes DNA repair refers to a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. ... Early detection of chemical agents Sociopolitical climate of chemical warfare While the study of chemicals and their military uses was widespread in China, the use of toxic materials has historically been viewed with mixed emotions and some disdain in the West (especially when the enemy were doing it). ... Biological Weapons: Friend or Foe? By Dom Harris There is great debate about whether biological weapons are good or bad, and whether the world should be concerned about their development. ... Biological Weapons: Friend or Foe? By Dom Harris There is great debate about whether biological weapons are good or bad, and whether the world should be concerned about their development. ... Jeanne Harley Guillemin is a medical anthropologist, a Professor of Sociology at Boston College and a senior fellow in the Security Studies Program at Massachusetts Institute of Technology. ...

Biography

Youth and education

He began studying chemistry and graduated from the University of Chicago 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 started in Harvard in 1961 as associate professor and taught undergraduate genetics for many years. For other uses, see University of Chicago (disambiguation). ... Year 1951 (MCMLI) was a common year starting on Monday (link will display the full calendar) of the Gregorian calendar. ... Linus Carl Pauling (February 28, 1901 – August 19, 1994) was an American scientist, peace activist, author and educator of German ancestry. ... X-ray crystallography, also known as single-crystal X-ray diffraction, is the oldest and most common crystallographic method for determining the structure of molecules. ... Jan. ... Harvard redirects here. ... Year 1961 (MCMLXI) was a common year starting on Sunday (link will display full calendar) of the Gregorian calendar. ... This article is about the general scientific term. ...

DNA breakthroughs

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 synthesised, so when DNA is synthesised 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. Year 1957 (MCMLVII) was a common year starting on Tuesday (link displays the 1957 Gregorian calendar). ... Dr. Franklin William Stahl (born 1929) is an American moelcular biologist. ... A summary of the three postulated methods of DNA synthesis The Meselson-Stahl experiment was an experiment by Matthew Meselson and Franklin Stahl to prove that DNA replication was semiconservative. ... E. coli redirects here. ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... For other uses, see Isotope (disambiguation). ...

He showed in the years that followed many more theories in relation to this with the help of Jean Weigle. In 1961 with Frank Stahl, Sidney 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. Year 1961 (MCMLXI) was a common year starting on Sunday (link will display full calendar) of the Gregorian calendar. ... Sydney Brenner (born 1927 January 13) is a British biologist active in the United States. ... François Jacob (born June 17, 1920 in Nancy, France) is a French biologist who, together with Jacques Monod, originated the idea that control of enzyme levels in all cells occurs through feedback on transcription. ... Ribosomal RNA (rRNA), a type of RNA synthesized in the nucleolus by RNA Pol I, is the central component of the ribosome, the protein manufacturing machinery of all living cells. ... The interaction of mRNA in a eukaryote cell. ... Recombination usually refers to the biological process of genetic recombination and meiosis, a genetic event that occurs during the formation of sperm and egg cells. ...

The Meselson effect

The Meselson laboratory studies the evolution of asexuality in bdelloid rotifers. Meselson described the "Meselson effect", which is when 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 shuffles genes between alleles during meiosis.^[1] Meselson's laboratory provided exciting 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 is a mechanism of generating variation that confers evolutionary advantage.^[2] It has been suggested that Parthenogenesis be merged into this article or section. ... Classes Seisonoidea Bdelloidea Monogononta The rotifers make up a phylum of microscopic, pseudocoelomate animals. ... An allele is any one of a number of alternative forms of the same gene occupying a given locus (position) on a chromosome. ... Genome is also a popular science book by Matt Ridley. ... For the figure of speech, see meiosis (figure of speech). ... For other uses, see Gene (disambiguation). ... A representation of the 3D structure of myoglobin showing coloured alpha helices. ... Synergy (from the Greek synergos, συνεργός meaning working together, circa 1660) refers to the phenomenon in which two or more discrete influences or agents acting together create an effect greater than that predicted by knowing only the separate effects of the individual agents. ... Dehydration (hypohydration) is the removal of water (hydro in ancient Greek) from an object. ... Genetic diversity is a characteristic of ecosystems and gene pools that describes an attribute which is commonly held to be advantageous for survival -- that there are many different versions of otherwise similar organisms. ... This article is about evolution in biology. ...

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. For other uses, see 1963 (disambiguation). ... Scud Missile The U.S. Arms Control and Disarmament Agency (ACDA) was established as an independent agency by the Arms Control and Disarmament Act (75 Stat. ... Early detection of chemical agents Sociopolitical climate of chemical warfare While the study of chemicals and their military uses was widespread in China, the use of toxic materials has historically been viewed with mixed emotions and some disdain in the West (especially when the enemy were doing it). ... Biological Weapons: Friend or Foe? By Dom Harris There is great debate about whether biological weapons are good or bad, and whether the world should be concerned about their development. ... Disarmament means the act of reducing or depriving arms i. ...

• Meselson was a leader in a 1980s effort attempting to show that "Yellow Rain" was not a Soviet biological warfare agent (as claimed by the CIA and the State Department), but bee droppings, a controversy that remains unresolved.^[3][4][5]

• 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.

T-2 (also known as Yellow Rain), a trichothecene mycotoxin, is a naturally-occurring mold byproduct of Fusarium spp fungus which is toxic to humans and animals. ... The CIA Seal The Central Intelligence Agency (CIA) is an American intelligence agency, responsible for obtaining and analyzing information about foreign governments, corporations, and individuals, and reporting such information to the various branches of the U.S. Government. ... Spores of anthrax were accidentally released from a military facility in the city of Sverdlovsk (formerly, and now again, Yekaterinburg) 900 miles East of Moscow on April 2, 1979. ...

References

External links

• Matthew Meselson
• The Meselson Laboratory
• The Meselson - Stahl Experiment