DNA

BBC Earth (Asia) - - Q&A -

Fran­cis Crick and James Wat­son are most of­ten as­so­ci­ated with the fa­mous ge­netic mol­e­cule, but their work in the 1950s came over 80 years af­ter the iden­ti­fi­ca­tion of DNA by a Swiss physi­cian search­ing for the ‘build­ing blocks’ of life. Friedrich Mi­escher had fo­cused on pro­teins in cells, but in 1869 he dis­cov­ered a strange sub­stance also lurk­ing in the nu­clei of the cells. He named it ‘nu­clein’, and sus­pected it would prove at least as vi­tal to cells as pro­teins. Crick and Wat­son were not the first to show he was right, ei­ther. Their cel­e­brated dis­cov­ery of DNA’s dou­ble he­lix struc­ture was prompted by key ex­per­i­ments by a team led by the Amer­i­can bio­chemist Oswald Avery. In 1944, work­ing at the Rock­e­feller Univer­sity in New York, they pub­lished the re­sults of painstak­ing stud­ies us­ing bac­te­ria that re­vealed that DNA passed ge­netic in­for­ma­tion from one or­gan­ism to another. This went against the ac­cepted wis­dom that pro­teins must be the car­ri­ers of ge­netic in­for­ma­tion, as DNA was ‘ob­vi­ously’ too sim­ple a mol­e­cule to per­form so com­plex a role. Crick and Wat­son agreed with Avery – but his own claim to a No­bel was blocked by scep­tics un­til the 1960s, by which time he was dead. RM

Fran­cis Crick (left) and James Wat­son

FRIEDRICH MI­ESCHER

OSWALD AVERY

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