Tuesday, January 8, 2019
Friday, January 4, 2019
Decoding Watson on PBS
I would like to thank John Kwok for alerting me to this new PBS documentary about James Watson, the controversial co-discoverer of DNA structure. I was tagged in a post about it on Facebook by John who saw Professor Ken Miller of Brown University share a link to the film. I agree wholeheartedly with Dr. Miller's assessment of the documentary. It is unafraid in confronting the racism and sexism of Watson while allowing the story of the discovery of the double helix to shine.
I must add one note. Though the story of discovery is certainly abbreviated, I think it worth mentioning one character who is left out in this telling. Jerry Donohue, an organic chemist from Wisconsin of whom few have ever heard. Donohue provided a crucial course correction right before Watson put the puzzle together (The Double Helix pg. 120). Watson had been using cardboard models of the four nitrogenous bases that constitute DNA. He made these flat cut-outs based the structures published in The Biochemistry of Nucleic Acids by J. N. Davidson. Watson was using the cardboard models to try and conjure how the bases might fit together to form a helix (which he knew must be the structure from Rosalind Franklin's famous photograph 51.) However, these cardboard models were misshapen. Homologous oxygen atoms poking out from the thymine and guanine models were in the enol (O-H) rather than the keto (=O) form. Jerry Donohue pointed this out and only then could Watson make the key observation that adenine pairs with thymine just as guanine pairs with cytosine. It was as though Donohue passed him the ball on the one-yard line!
When I read Watson's The Double Helix for the first time last year I was startled to learn about Jerry Donohue and hope he is also remembered for this serendipitous correction!
I must add one note. Though the story of discovery is certainly abbreviated, I think it worth mentioning one character who is left out in this telling. Jerry Donohue, an organic chemist from Wisconsin of whom few have ever heard. Donohue provided a crucial course correction right before Watson put the puzzle together (The Double Helix pg. 120). Watson had been using cardboard models of the four nitrogenous bases that constitute DNA. He made these flat cut-outs based the structures published in The Biochemistry of Nucleic Acids by J. N. Davidson. Watson was using the cardboard models to try and conjure how the bases might fit together to form a helix (which he knew must be the structure from Rosalind Franklin's famous photograph 51.) However, these cardboard models were misshapen. Homologous oxygen atoms poking out from the thymine and guanine models were in the enol (O-H) rather than the keto (=O) form. Jerry Donohue pointed this out and only then could Watson make the key observation that adenine pairs with thymine just as guanine pairs with cytosine. It was as though Donohue passed him the ball on the one-yard line!
When I read Watson's The Double Helix for the first time last year I was startled to learn about Jerry Donohue and hope he is also remembered for this serendipitous correction!
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