Who is Maurice Wilkins?

Wilkins followed his colleague to King’s in 1946 to work at the new Biophysics Research Unit set up by Randall and the Royal Society and Medical Research Council to investigate the structure of living material. His early work at King’s was concerned with the genetic effects of ultrasound but, drawing on the pioneering work of Caspersson and Brachet, he and Bill Seeds began studies to measure nucleic acids using techniques of ultraviolet dichromism and interference microscopy. Wilkins was drawn to the study of DNA, already the subject of considerable enquiry following the work of Frederick Griffith in the 1920s, Oswald Avery, Macleod and McCarty, and Max Delbruck and Salvador Luria in the 1940s that had suggested an important role for the molecule in chromasomal activity and bacterial transformation and which pointed to the implication of DNA and not protein in genetic processes. The filament structure of elongated DNA samples implied a regular molecular structure, a suspicion reinforced by the chemical analysis of Avery and others showing that the polymer displayed regular repetition of bases perpendicular to the molecule and a balance in the quantities of adenine, thymine, guanine and cytosine.

Building on the work of William Astbury in the 1930s and 40s that had produced blurred x-ray diffraction pictures of DNA, Wilkins began to investigate its structure with Raymond Gosling using diffraction equipment set up by Randall and Gosling to study ram spermatozoa. They obtained good pictures with moist samples of DNA supplied by Signer and Schwander. Like other crystalline diffraction pictures, these resembled a pattern of dots in different positions and of varying degrees of resolution and clarity. One of the most important contributions of Maurice Wilkins, Rosalind Franklin and their colleagues was in gradually and painstakingly improving the quality of pictures sufficient to allow the accurate measurement of angles and distances between atoms from which inferences as to the precise, possibly helical, architecture of the molecule might be obtained. They did this in part by subtly and systematically adjusting the relative humidity of the samples of DNA and taking x-ray photographs of the so-called A configuration of the molecule. The complex patterns of diffraction belied the underlying symmetry and comparative simplicity of the molecular framework of DNA. However, diffraction studies alone were not sufficient to reveal exact molecular alignments that determined the double-helix: mathematical intuition, the insight of chemical analysis and model-building were necessary to construct a viable hypothetical that could be tested subsequently with follow-up x-ray analysis. Ultimately, it was this collision and co-operation of methods and minds that unlocked the puzzle of heredity, the moment when the age-old potential of the DNA molecule to reveal its own structure was realised.





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		Who is Maurice Wilkins? DNA work at King’s College London Wilkins followed his colleague to King’s in 1946 to work at the new Biophysics Research Unit set up by Randall and the Royal Society and Medical Research Council to investigate the structure of living material. His early work at King’s was concerned with the genetic effects of ultrasound but, drawing on the pioneering work of Caspersson and Brachet, he and Bill Seeds began studies to measure nucleic acids using techniques of ultraviolet dichromism and interference microscopy. Wilkins was drawn to the study of DNA, already the subject of considerable enquiry following the work of Frederick Griffith in the 1920s, Oswald Avery, Macleod and McCarty, and Max Delbruck and Salvador Luria in the 1940s that had suggested an important role for the molecule in chromasomal activity and bacterial transformation and which pointed to the implication of DNA and not protein in genetic processes. The filament structure of elongated DNA samples implied a regular molecular structure, a suspicion reinforced by the chemical analysis of Avery and others showing that the polymer displayed regular repetition of bases perpendicular to the molecule and a balance in the quantities of adenine, thymine, guanine and cytosine. Building on the work of William Astbury in the 1930s and 40s that had produced blurred x-ray diffraction pictures of DNA, Wilkins began to investigate its structure with Raymond Gosling using diffraction equipment set up by Randall and Gosling to study ram spermatozoa. They obtained good pictures with moist samples of DNA supplied by Signer and Schwander. Like other crystalline diffraction pictures, these resembled a pattern of dots in different positions and of varying degrees of resolution and clarity. One of the most important contributions of Maurice Wilkins, Rosalind Franklin and their colleagues was in gradually and painstakingly improving the quality of pictures sufficient to allow the accurate measurement of angles and distances between atoms from which inferences as to the precise, possibly helical, architecture of the molecule might be obtained. They did this in part by subtly and systematically adjusting the relative humidity of the samples of DNA and taking x-ray photographs of the so-called A configuration of the molecule. The complex patterns of diffraction belied the underlying symmetry and comparative simplicity of the molecular framework of DNA. However, diffraction studies alone were not sufficient to reveal exact molecular alignments that determined the double-helix: mathematical intuition, the insight of chemical analysis and model-building were necessary to construct a viable hypothetical that could be tested subsequently with follow-up x-ray analysis. Ultimately, it was this collision and co-operation of methods and minds that unlocked the puzzle of heredity, the moment when the age-old potential of the DNA molecule to reveal its own structure was realised.


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