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Detection of a Strange Particle

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Detection of a Strange Particle 10 extraordinary papers Within days, Watson and Crick had built a identify the full set of codons was completed in forensics, and research into more-futuristic new model of DNA from metal parts. Wilkins by 1966, with Har Gobind Khorana contributing applications, such as DNA-based computing, immediately accepted that it was correct. It the sequences of bases in several codons from is well advanced. was agreed between the two groups that they his experiments with synthetic polynucleotides Paradoxically, Watson and Crick’s iconic would publish three papers simultaneously in (see go.nature.com/2hebk3k). structure has also made it possible to recog- Nature, with the King’s researchers comment- With Fred Sanger and colleagues’ publica- nize the shortcomings of the central dogma, ing on the fit of Watson and Crick’s structure tion16 of an efficient method for sequencing with the discovery of small RNAs that can reg- to the experimental data, and Franklin and DNA in 1977, the way was open for the com- ulate gene expression, and of environmental Gosling publishing Photograph 51 for the plete reading of the genetic information in factors that induce heritable epigenetic first time7,8. any species. The task was completed for the change. No doubt, the concept of the double The Cambridge pair acknowledged in their human genome by 2003, another milestone helix will continue to underpin discoveries in paper that they knew of “the general nature in the history of DNA. biology for decades to come. of the unpublished experimental results and Watson devoted most of the rest of his ideas” of the King’s workers, but it wasn’t until career to education and scientific administra- Georgina Ferry is a science writer based in The Double Helix, Watson’s explosive account tion as head of the Cold Spring Harbor Labo- Oxford, UK. A revised edition of her biography of the discovery, was published in 1968 that ratory in Long Island, New York, and serving Dorothy Crowfoot Hodgkin has just been it became clear how they obtained access to (briefly) as the first head of the US National published by Bloomsbury Reader. those results. Franklin had died of cancer a Center for Human Genome Research, now the 1. Watson, J. D. & Crick, F. H. C. Nature 171, 737–738 (1953). decade previously; her death prevented her National Human Genome Research Institute. 2. Avery, O. T., MacLeod, C. M. & McCarty, M. J. Exp. Med. 79, from sharing the Nobel prize awarded to Always outspoken, he was eventually removed 137–158 (1944). Watson, Crick and Wilkins in 1962. from his emeritus position at Cold Spring Har- 3. Hershey, A. D. & Chase, M. J. Gen. Physiol. 36, 39–56 The immediate reception of the double-he- bor when he repeatedly aired controversial (1952). 4. Pauling, L., Corey, R. B. & Branson, H. R. Proc. Natl Acad. 9 lix model was surprisingly muted ,perhaps opinions about genetics, race and intelligence. Sci. USA 37, 205–211 (1951). because there was no obvious mechanism Crick continued to tackle hard problems in 5. Cochran, W., Crick, F. H. & Vand, V. Acta Crystallogr. 5, to explain its role in protein synthesis. In a science, moving in 1977 from Cambridge to the 581–586 (1952). 6. Vischer, E. & Chargaff, E. J. Biol. Chem. 176, 703–714 landmark talk in 1957, Crick proposed that Salk Institute in La Jolla, California, where he (1948). the base sequence encoded the sequence spent the rest of his life working on the neural 7. Wilkins, M. H. F., Stokes, A. R. & Wilson, H. R. Nature 171, of amino acids in a protein, and that protein basis of consciousness17 and, specifically, of 738–740 (1953). 8. Franklin, R. E. & Gosling, R. G. Nature 171, 740–741 (1953). production involved RNA both as a template visual perception. He died in 2004, aged 88. 9. Olby, R. Nature 421, 402–405 (2003). and as an ‘adaptor’ that would enable amino The double helix put genetics on a 10. Brenner, S. Proc. Natl Acad. Sci. USA 43, 687–694 (1957). acids to be attached to one another in the right physical footing that would shed light on 11. Crick, F. H. C. Symp. Soc. Exp. Biol. 12, 138–163 (1958). 12. Meselson, M. & Stahl, F. W. Proc. Natl Acad. Sci. USA 44, order. He also supported the suggestion — almost every aspect of modern biology and 671–682 (1958). originally made informally by the physicist medicine. Examples include the migration of 13. Lehman, I. R., Bessman, M. J., Simms, E. S. & Kornberg, A. George Gamow to the members of the ‘RNA human populations throughout history; ecol- J. Biol. Chem. 233, 163–170 (1958). Tie Club’ convened by Gamow and Watson, ogy and biodiversity; cancer-causing muta- 14. Nirenberg, M. W. & Matthaei, J. H. Proc. Natl Acad. Sci. USA 47, 1588–1602 (1961). but also independently proposed by biolo- tions in tumours and their drug treatment; 15. Crick, F. H. C., Barnett, L., Brenner, S. & Watts-Tobin, R. J. gist Sydney Brenner10 — that triplets of bases surveillance of microbial drug resistance in Nature 192, 1227–1232 (1961). (which Brenner called codons) encode the hospitals and the global population; and the 16. Sanger, F., Nicklen, S. & Coulson, A. R. Proc. Natl Acad. Sci. USA 74, 5463–5467 (1977). 20 amino acids commonly found in proteins. diagnosis and treatment of rare congenital dis- 17. Crick, F. H. C. The Astonishing Hypothesis: The Scientific Finally, Crick expounded what he called the eases. DNA analysis has long been established Search for the Soul (Simon & Schuster, 1994). ‘central dogma’ of biology: that information can flow from nucleic acids to proteins, but High-energy physics not the other way round11. These predictions were confirmed by experiment in the next few years. In 1958, the biochemists Matthew Meselson and Franklin Detection of a Stahl showed that one DNA strand acts as a template for the formation of a new strand12. strange particle The same year, Arthur Kornberg and his colleagues published their discovery of the Taku Yamanaka enzyme DNA polymerase13, which adds bases to newly forming strands. Messenger RNA, In 1947, scientists found a previously unseen particle, which transfer RNA and ribosomal RNA were all is now called a neutral kaon. This work led to the discovery of quickly identified. elementary particles known as quarks, and ultimately to the In 1961, Marshall Nirenberg and Heinrich Mat- thaei were the first to crack part of the genetic establishment of the standard model of particle physics. code, demonstrating that bacterial extracts synthesize only the amino acid phenyl alanine from RNA that contains just one type of RNA In the late 1940s, the physicists George gap between the lead plate and the vertex of base14 (uracil; U). The same year, Crick, his indis- Rochester and Clifford Butler1 observed the tracks indicated that an invisible neutral pensable female technician Leslie Barnett and something unusual in their charged-particle particle had been produced in the plate, had their co-workers reported mutation studies that detector. They were studying the inter actions travelled for a short distance and had then confirmed the existence of the triplet-based between high-energy cosmic rays and a lead decayed into two visible charged particles. code15, and which therefore suggested that the plate in the detector when they spotted The mass of the neutral particle was about codon for phenylalanine was UUU. The race to V-shaped particle tracks (Fig. 1a). The small 1,000 times that of an electron, implying 36 | Nature | Vol 575 | 7 November 2019 ©2019 Spri nger Nature Li mited. All ri ghts reserved. ©2019 Spri nger Nature Li mited. All ri ghts reserved. a b Mesons Baryons 0 + – K K – Neutron Proton ds us ddu uud – η π0 + – 0 0 + – π – – π – Σ Σ Λ Σ du – – – uu, dd ud sdd suu uu, dd, ss η′ sdu – – su sd ssd ssu – Strangeness K– K0 Ξ– Ξ0 Charge Figure 1 | Particle detection that led to a better understanding of fundamental of many more particles following Rochester and Butler’s work led to a model12,13 physics. a, In 1947, Rochester and Butler1 analysed the particles produced in which all of the known mesons and baryons (two classes of particle) consist of when high-energy cosmic rays hit a lead plate (the broad central stripe) in a elementary particles called up (u), down (d) and strange (s) quarks, along with their charged-particle detector. In certain photographs, they spotted evidence of a antiparticles (denoted by overbars). The η, η′ and π0 mesons comprise mixtures previously undetected, invisible neutral particle decaying into two visible charged of quark pairs. The mesons and baryons are arranged by their strangeness particles, which were identified by tracks (labelled with arrows). b, The discovery (a quantity that is related to the presence of strange quarks) and electric charge. that it must be a previously unreported type However, a strange particle that has S = –1, applies a charge-conjugation transformation of particle. This discovery paved the way for for example, cannot decay into particles that (in which particles are replaced by their many puzzles and surprises in particle physics have S = 0 through the strong force, because antiparticles), the right-handed neutrino in the decades that followed. strangeness would not be conserved. Instead, becomes a right-handed antineutrino, which At the time of Rochester and Butler’s work, this decay must occur much more slowly does exist. The weak force therefore seemed protons, neutrons, electrons and particles through the weak nuclear force, which allows to conserve CP symmetry (symmetry under called pions (short for π mesons) had been total strangeness to change.
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