Biology Achievement Timeline, 1960-75

1960

• Jonas Salk, developer of the polio vaccine, establishes the Salk Institute for Biological Studies on 27 acres in La Jolla, California; opens in 1963; now houses 14 research units.

1961

• Howard M. Dintzis establishes that a type of ribonucleic acid called “transfer-RNA” puts down one amino acid after another in sequence to form a protein.
• Francois Jacob, Sydney Brenner, and Matthew Meselson show the existence of “messenger RNA” using the density gradient method.
• Marshall Nirenberg and J.H. Mitthaei break the genetic code and establish what is known as the central dogma of biology: that information is transmitted from DNA to RNA and results in the irreversible synthesis of proteins; published in the Proceedings of the National Academy of Sciences.

1962

• Alexander Rich of MIT proposes the concept of “RNA world” to explain an early stage of life development on earth (origin of life, ambiogenesis) where there existed no DNA or proteins.
• Rodney Robert Porter determines the peptide-chain structure of an antibody, for which he wins the Nobel Prize in Physiology in 1972 (with Gerald M. Edelman).
• Sol Speigelman develops a method to cause DNA and RNA to pair with each other, and determines how proteins are manufactured through DNA passing a message to RNA; lays groundwork for advances in recombinant DNA in the early 1970s.
• Emile Zuckerkandl and Linus Pauling publish a paper that introduces the idea of what will become known as the “molecular clock,” involving the mutation rate of biomolecules.

1963

• Roger W. Sperry published his Chemoaffinity Hypothesis that stated that neurons make connections with their targets based on interactions with specific molecular markers and, therefore, that the initial wiring diagram of an organism is indirectly determined by its genotype. The markers are generated during cellular differentiation and aid with, and act as, guidance cues for their respective axon.
• Alexander Rich discovers polyribosomes (polysomes, a.k.a. ergosomes), groups of ribosomes that read a single strand of mRNA simultaneously.

1964

1965

1966

• Marshall Nirenberg and his team crack the genetic code, proving that a sequence of three nucleotides determines each of the 20 amino acids that appear in the code – called the standard or canonical amino acids.

1967

• Microbiologist Thomas Brock publishes “Life at High Temperatures” in the journal Science, summarizing his research on bacteria living in the hot springs of Yellowstone; leads to the study of “extremophiles” and advances the new field of biotechnology.
• Evolutionary biologist Lynn Margulis (1938-2011) argues that the eukaryotic cell came about first as a kind of colony of of prokaryotes; that our nucleus, mitochrondria, and chloroplasts had their origins first as prokaryotic cells.

1968

• Harvard’s Matthew Meselson demonstrates the enzymatic basis for the idea of “host-directed restriction,” a process by which cells recognize and destroy foreign DNA.
• Motoo Kumura introduces the neutral theory of molecular evolution.

1969

• Studying the interaction of starfish and mussels, ecologist Robert T. Paine (1933-2016) introduces a popular idea in conservation biology – the “keystone species,” – a creature that has a disproportionately large impact on its environment relative to its abundance; for example, wolves, sea otters, jaguars, starfish, and beavers. Relatedly, Payne coins the phrase “trophic cascades,” an ecological concept that describes indirect interactions that can control whole ecosystems (see link: effects on forests with elimination of wolves).
• A meterorite hit earth about 2 miles south of Murchison, Victoria, New South Wales on September 28. Fragments analyzed at the NASA Ames Research Center revealed the first convincing evidence of amino acids of extraterrestrial origin, confirming the Miller-Urey experiment of 1953. Of the 90 amino acids found in the meteorite samples, only 19 are found on earth.

1970

1971

1972

• Paleontologists Stephen Jay Gould and Niles Eldridge develop the theory of punctuated equilibrium, questioning Darwin’s theory of phyletic gradualism, and Charles Lyell in geology.

1973

• Herbert Boyer (UCSF), Stanley Cohen (Stanford), and Paul Berg (Stanford) perform the first experiments in genetic engineering. DNA molecules are cut into pieces by restriction enzyme “scissors” and inserted into the bacterium Escherichia coli to perform there as new genes.  

1974

1975

• Biologist Allan C. Wilson (1934-1991) and doctoral student Marie-Claire King (b. 1946) publish in the journal Science (April 11) that chimps and humans are structurally 99% similar in their genetics; express view that the manner and timing of gene expression is key to morphological differences.