© 2003 American Thoracic Society
April 25, 1953Three Papers, Three LessonsFifty years ago, Nature published three articles in its April 25 issue. All three dealt with the structure of deoxyribose nucleic acid, DNA. The authors of one paper, Watson and Crick (1), have become household names. Few remember Franklin (2) and Wilkins (3), the senior authors of the other two papers. The irony is that Watson and Crick based their model almost completely on the experimental findings of Franklin and Wilkins. The three papers contain three lessons for authors. After moving to King's College, London in 1947, Maurice Wilkins began research on the structure of DNA (4). In January 1951, Rosalind Franklin also moved to King's (5). Both worked on the structure of nucleic acids, but they clashed and one could not abide the other (5). Having no one to talk to about his work, Wilkins discussed his frustrations—and research findings—with an old friend, Francis Crick, working in Cambridge University. Crick had a junior collaborator, James Watson, and the two had a warm and buoyant relationship in contrast to the antipathy between Franklin and Wilkins. On January 30, 1953, Watson visited King's. Without Franklin's permission, Wilkins showed her data to Watson—in particular, an X-ray crystallograph (of May 1952) that provided unquestionable evidence of the helical structure of DNA. The photograph struck Watson with the force of revelation (5, 6). He sketched the pattern on the margin of his newspaper, and brought it back to Crick. Within four weeks, Watson and Crick had completed their model for the structure of DNA. In developing their model, Watson and Crick never once touched or looked directly at a fiber of DNA (4, 6, 7). The article has no experiments, and consists of speculation based primarily on the experimental findings of the King's researchers. (The verb to theorize is conjugated as: I model, you hypothesize, and they speculate [8].) In a footnote to a 1954 paper, Crick and Watson wrote, "we wish to point out that without this data [King's] the formulation of our structure would have been most unlikely, if not impossible" (9). And in 1999 Watson admitted, "the Franklin photograph was the key event" (5). The first lesson is that collaborating with faculty colleagues is more profitable than competing against them. Also working in King's were Alec Stokes and Bruce Fraser. By July 1951, Stokes had convincing mathematical evidence that DNA had a helical structure (5). In November 1951, Fraser built a model that turned out to have all the key elements correct—a helical shape, phosphates on the outside, and stacked bases separated by a distance of 3.4 angstroms—except for the number of chains (5). This research was completed before Watson began working with Crick. But neither Stokes nor Fraser published their findings. In her paper, Franklin (2) wrote "in this laboratory ... Stokes (unpublished) ... and Wilkins were the first to propose such [helical] structures for nucleic acid as a result of direct studies of nucleic acid fibres..." In their paper, Watson and Crick (1) referred—grudgingly (5, 6)—to the Fraser model but dismissed it as "rather ill-defined, and for this reason we shall not comment on it." The second lesson is that research has no value if unpublished. The leap of Watson and Crick would have seemed less spectacular had publications from Stokes and Fraser preceded it. The point was well put by a subsequent editor of Nature (10): "Research is incomplete if it remains unpublished. People who have slaved away for months or years on a project that never finds its way into print might just as well have dug their gardens." The third lesson comes from the contrasting prose presentations in the three papers. Watson and Crick have something important to say, they say it clearly, and then shut up. The article exemplifies the three cardinal qualities of good scientific writing: be brief, clear, simple (11, 12). Their text contains half the number of words (a mere 842 in total) used by Franklin or Wilkins. Verbosity is always a blemish on writing, whereas parsimony with words is rarely a vice and never a fault. Cutting the number of words by half makes a manuscript twice as good, only it takes twice as long to write. The Watson and Crick article contains no padding, and every word carries its weight. Their report is clear and precise. Precision is a hallmark of a good experimentalist. Yet many scientific manuscripts are imprecise and vague. The only window a reviewer has into the laboratory of an investigator is through the manuscript he or she writes. But many authors don't seem to realize that a sloppily written manuscript causes reviewers to believe that the research was also done in a sloppy manner. The cardinal sin in scientific communication is vagueness, not bad grammar. A clumsy sentence is preferable to an ambiguous sentence. Much ambiguity arises from schoolroom teaching about never repeating the same word twice in the same sentence. This false grace of elegant variation causes confusion because badly chosen synonyms distort the real meaning. In describing the key element of their model, Watson and Crick are not afraid of repetition: The novel feature of the structure is the manner in which the two chains are held together by the purine and pyrimidine bases ... only specific pairs of bases can bond together. These pairs are: adenine (purine) with thymine (pyrimidine), and guanine (purine) with cytosine (pyrimidine). One of the best measures of a person's expertise in a field is the ability to explain complex aspects in simple words. With the Watson and Crick paper, you never need to read a sentence twice to understand the meaning. Some authors see that simple words are good enough for the Declaration of Independence, but want something more grandiloquent for their manuscript. The papers by Franklin and Wilkins are written in an obscure style and loaded with arcane jargon, as if the authors were set on befuddling readers. Take this sentence from the Franklin paper (2): For a smooth single-strand helix the structure factor on the nth layer line is given by:
where Jn(u) is the nth-order Bessel function of u, r is the radius of the helix, and R and And this sentence from the Wilkins paper (3): Third, if the nucleotide is extended as an arc of a circle in a plane at right-angles to the helix axis, and with centre at the axis, the intensity of the system of Bessel function layer-line streaks emanating from the origin is modified owing to the phase differences of radiation from the helices drawn through each point on the nucleotide. Although the Franklin and Wilkins papers are rich in experimental findings, the poverty of the presentations—contrasted with the brief, clear, and simple prose of Watson and Crick—assured their underappreciation and early obsolescence. Researchers are often less worried that their article will be considered unreadable than risking the use of simple words and be judged unsophisticated. A former editor of the BMJ (13) commented, "If a colleague tells a scientist that his latest article is difficult to understand, the writer is more likely to assume that his colleague is unintelligent than that his article is unintelligible." Opening and closing sentences are difficult to get right. The first two sentences of the Wilkins article, The structure of deoxypentose nucleic acid is the same in all species (although the nitrogen base ratios alter considerably) in nucleoprotein, extracted or in cells, and in purified nucleate. The same linear group of polynucleotide chains may pack together parallel in different ways to give crystalline1–3, semi-crystalline or paracrystalline material. consist of a typical warm-up, whereas Watson and Crick get straight to the point: We wish to suggest a structure for the salt of deoxyribose nucleic acid (D.N.A.). [Incidentally, DNA is the sole abbreviation they introduce—Editor.] This structure has novel features which are of considerable biological interest. Note how they use two short sentences to avoid ambiguity (14). They could have joined the two statements: "We wish to suggest a structure for the salt of deoxyribose nucleic acid (DNA) that has novel features which are of considerable biological interest." But then you wouldn't know whether it is the salt or the structure that has the novel features. They could have begun the second sentence with "This has novel..." But then you wouldn't know what "This" refers to. Instead, they repeat the word "structure" and avoid ambiguity. Only in one sentence, their conclusion (1), do they hint at how the DNA structure explains the secret of genetic reproduction: It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material. The truly important is better communicated in a whisper than a shout. REFERENCES
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are the radial and azimuthal co-ordinates in reciprocal space2; this expression leads to an approximately linear array of intensity maxima of the type observed, corresponding to the first maxima in the functions J1, J2, J3, etc.
