Maxine Singer

Life, the movie

Fifty years after revealing the structure of DNA, James Watson looks back.

George Beadle: from genes to proteins

George W. Beadles life spanned much of the period during which genetics changed from an abstract to a molecular science. Beadle himself catalysed the transition from classical to molecular genetics when, together with Edward Tatum, he discovered that each gene is linked to the production of a protein. This article traces his life from a modest farm to the centre of biology and a principal role in the development of the scientific enterprise.

A centennial: George W. Beadle, 1903-1989.

GEORGE BEADLE was a quadruple-threat man—scientist, teacher, administrator, and public citizen. He excelled in each. Furthermore, he did what very few geneticists did in his time: he studied three different organisms and made outstanding discoveries in every case. He followed his interests and

Great Teachers for STEM

Many countries are striving to develop the human resources required to advance science and technology. Success requires a system of education that prepares young people for life in todays complex societies. The Obama administration has recently stressed the need to strengthen science, technology, engineering, and mathematics (STEM) education in the United States. U.S. Secretary of Education Arne Duncan clearly understands that the quality of STEM teaching is of singular importance to the success of students, requiring “great teachers, who know the content.”* Herein lies a major challenge: How to develop and cultivate great STEM teachers?

Leon Heppel and the early days of RNA biochemistry.

Today, machines turn out the sequence of a million DNA bases in a day. Fifty years ago, when the chemical and biochemical tools for studying DNA and RNA were at best rudimentary, such a machine was unimaginable. Then, the cutting edge was Erwin Chargaff ’s demonstration, in 1948, that the base composition of DNA could be reliably determined. His discovery that all DNAs contain equal amounts of adenine and thymine and similarly of guanine and cytosine depended on applying two recent developments: partition chromatography and the absorption spectra of nucleic acid constituents. DNA chemistry took a huge step forward when James D. Watson and Francis Crick, using Chargaff ’s data, constructed the double helical model of DNA. In contrast, insights into RNA structure lagged behind, thus hampering progress in understanding how DNA carries out its genetic function. At the beginning of the 1950s, studies on RNA structure in the United States came mainly from the laboratories of Waldo Cohn and C. E. Carter. Progress was slow because of the difficulty of determining whether the internucleotide bond was 5 to 3 or 5 to 2 , because the primitive methods available could not cope with the instability of RNA compared with DNA, and because of the still unrecognized existence of several types of RNA. The impetus for further advances in DNA and RNA biochemistry emerged not from structural investigations but from studies of the enzymology of phosphate-containing coenzymes and nucleotides. Much of that activity was spurred by a group of extraordinary biomedical scientists, who partly through the accidents of World War II assignments to the United States Public Health Service found themselves at war’s end together at the still fledgling National Institutes of Health (NIH) (1). At the time NIH had little prestige compared with academic institutions. What it did offer was regular support and a great deal of scientific freedom. Leon Heppel, Arthur Kornberg, Herbert Tabor, and Bernard Horecker used part of their freedom to learn biochemistry. Horecker, already an experienced enzymologist, helped them find their way. Their primary educational tool was a private, daily, lunchtime journal club; according to legend, the only day off was Christmas. Kornberg was the dominant personality. Years later, long after he had left the NIH and the club was open to other colleagues and even postdoctoral fellows, any proposed change in the lunch club format elicited the question: “What would Arthur think?” The biochemistry of phosphate-containing compounds became a central interest of several in the original lunch club group. Horecker’s work led to a description of the pentose phosphate pathway (2). Kornberg began working on the enzymatic synthesis of pyrophosphate, coenzymes, and nucleotides, and he has told the story about how these investigations led to the discovery of DNA polymerase I in the three years after he left the NIH for Washington University in 1953 (1, 3). Heppel (Fig. 1) had earned a Ph.D. in biochemistry from the University of California at Berkeley in 1937 and an M.D. in 1941 from the University of Rochester. After completing a medical internship at Strong Memorial in Rochester, he carried out toxicology research at the NIH during the war years. By 1950 he, together with his long time colleague Russell J. Hilmoe, THE JOURNAL OF BIOLOGICAL CHEMISTRY Vol. 278, No. 48, Issue of November 28, pp. 47351–47356, 2003

SV40 host-substituted variants: a new look at the monkey DNA inserts and recombinant junctions.

The available monkey genomic data banks were examined in order to determine the chromosomal locations of the host DNA inserts in 8 host-substituted SV40 variant DNAs. Five of the 8 variants contained more than one linked monkey DNA insert per tandem repeat unit and in all cases but one, the 19 monkey DNA inserts in the 8 variants mapped to different locations in the monkey genome. The 50 parental DNAs (32 monkey and 18 SV40 DNA segments) which spanned the crossover and flanking regions that participated in monkey/monkey and monkey/SV40 recombinations were characterized by substantial levels of microhomology of up to 8 nucleotides in length; the parental DNAs also exhibited direct and inverted repeats at or adjacent to the crossover sequences. We discuss how the host-substituted SV40 variants arose and the nature of the recombination mechanisms involved.

Biology in public policy

On March 3, 1863, Senator Henry Wilson of Massachusetts rose in the Senate chamber to, as he told his colleagues, “take up a bill...to incorporate the National Academy of Sciences.” He read two short paragraphs concerning membership and the obligation of the Academy to “whenever called upon by any department of the Government, investigate, examine, experiment, and report upon any subject of science or art.” The Senate passed the bill by voice vote, and a few hours later, the House passed it without comment. Later that evening, President Abraham Lincoln signed the bill into law. In the century and a half since 1863, the National Academy of Sciences (NAS) has grown from a small band of 50 charter members—each of whom was specified in the founding legislation—to an organization of more than 2,500 national members and foreign associates. In 1916, the Academy created the National Research Council, which today recruits thousands of specialists each year from the scientific and technological communities to participate in the Academys advisory work. The establishment of the National Academy of Engineering in 1964 and the Institute of Medicine in 1970 resulted in a multifaceted institution that investigates issues ranging widely across the sciences, technology, and health. The charter members of the Academy, who met for the first time on April 22, 1863, in the chapel at New York University, scarcely could have envisioned what their fledgling organization would become. To celebrate the Academy’s sesquicentennial, the Arthur M. Sackler Colloquia of the National Academy of Sciences, with additional support from the W. M. Keck Foundation, the Ford Foundation, and the Richard Lounsbery Foundation, held a meeting in Washington, DC, on October 16–18, 2013, entitled “The National Academy of Sciences at 150: Celebrating Service to the Nation.” The meeting began the evening of October 16 with the … [↵][1]1E-mail: solson{at}comcast.net. [1]: #xref-corresp-1-1