It was Watson and Crick who discovered the double helix, even if Franklin did write something down about a single helix from a previous photo that they didn't read.
She might have measured those parameters, but she still didn't know what she had (as evidenced by how she subsequently spent a ton of time on Z-dna)
dekhn•32m ago
That's the first actual evidence I've seen (I am a DNA nerd and have been trying to understand what her contribution to the intellectual discovery of DNA's double-helix antiparalel).
I would need to go back to Judson's book (Eighth Day of Creation) and see if he actually missed this.
dnautics•27m ago
FTA:
The new paper does not challenge Watson and Crick’s achievement. Their model of DNA, rushed out in a brief article in Nature after Watson caught his glimpse of photograph 51, went well beyond Franklin’s understanding. [Watson and Crick's model's] two strands running in opposite directions and zipperlike arrangement of complementary base pairs explained how the molecule could carry genetic information and be copied each time a cell divides. “The fact that it was a helix, you know, was not the most exciting aspect of this structure,” says Soraya de Chadarevian, a science historian at the University of California, Los Angeles. Indeed, by 1952, other researchers striving to make sense of the molecule also suspected it was helical. [for example Pauling, who at one point thought DNA might be an alpha helix-like structure]
Teever•12m ago
As for base complementarity it seems likely that she would have made that leap from everything else that she knew of at the time, but I'm no expert on this subject and have not read her notes.
[0] https://youtu.be/_1FUqUSNPeI?t=2487