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by pazimzadeh 1152 days ago
> She supposedly sat on the image for months without realizing its significance, only for Watson to understand it at a glance.

That's not the lore as I learned it. The lore is that Franklin sat on the data for months before analyzing it (she wanted to collect more data). Then W+C visited her lab and saw the data, but did not instantly understand it. Instead, the lore is that they figured out the structure of the DNA through a combination of going on daily walks, playing with models, and taking LSD.

It is Linus Pauling who would have been able to instantly figure out the structure of DNA by glancing at Photograph 51. His initial theory had been that the phosphates were on the inside of the structure, which in hindsight would never work because the negative charges would repel each other.

Source: Don't remember the primary source, but we covered it in Martin Stranathan's AP Bio class in high school

7 comments

Linus Pauling may have been the better chemist, but Francis Crick was better prepared to figure out the structure from that particular photograph.

The necessary analysis technique was first developed 2 years earlier, in a paper that Crick was the lead author on. Chance favors the prepared mind. And Crick was extremely well-prepared for this task.

As I learned it, Photograph 51 was so good that anybody with any crystallography experience would have been able to tell the structure at a glance. Exactly, like you said she wanted to sit on it and get more data because, allegedly, she had observed Hoogsteen base pairing, or some other non-canonical base pair that escapes me.
Today, sure. It's famous.

But as https://www.tandfonline.com/doi/pdf/10.1080/1464518031000160... points out, the analysis technique that makes it possible to deduce the structure from the image was first developed 2 years earlier in a paper by Crick, Cochran and Vand. Note the lead author. In 1953, Francis Crick was one of a handful of people on the planet who would have made the connection. In fact he was able to make it from James Watson's description of the photograph! Rosalind Franklin can be pardoned for having failed to make the connection.

But, but... we were always told that Franklin was an expert crystallographer and that Watson and Crick were bumbling amateurs who knew nothing, NOTHING, about crystallography!
Franklin was. Which is why she was the one who actually produced that image. And if the problem could have been solved by deducing the crystalline structure from variant A, she would have been a much better choice.

The fact that Crick was the world expert on the one obscure thing about crystallography that mattered here doesn't mean that Franklin wasn't the real expert. Every expert has gaps in their knowledge.

Gosling produced the image, not Franklin.
Using Fourier transforms doesn't seem obscure to me. It seems to me -- today -- that it is an obvious thing to do. It probably was back then, too, if you were a physicist who was good at math.
The photograph tells you the gross structure ("it's a helix") and also that it's a double helix. It doesn't have any real information of the specific structure/location of the bases. That only came later when full x-ray crystallography of 3D crystals (not 2D pulled fibers) was done.
You likely know a lot more than I do about this story, but I will note this piece also says:

Franklin had put the photograph aside to concentrate on the A form. She was preparing to transfer to Birkbeck College, also in London, and had been instructed to leave her DNA work behind.

Schrodinger predicted the double helix structure of DNA decades before it was observed to be fair.
Maybe he did and maybe he didn't, but what's the value of a completely speculative prediction?
Inspiration, apparently? According to wikipedia, Watson and Crick both credited Schrödinger's book (what is life) as a source of inspiration for their initial research.
Apart from the amusement that might be had in making it, you never know if further evidence might one day cast new light on it.
Where? What is Life is an astounding piece. It influenced Watson, Crick and other biologists, but didn't predict a double helix.
It's a wonderful book. I am proud to have a copy :)
Erwin Chargaff himself a chemist, knew very well the proportion of the bases in DNA since he'd discovered it but didn't put two and two together (Chargaff's ratio).

https://www.encyclopedia.com/science-and-technology/biology-...

Schrodinger predicted some "aperiodic crystal" storing information. No mention of double helix.
This is false. He wrote something about aperiodic Crystal.
I think the real issue is that her boss shared her data with W&C without her permission.
That's not true. Wilkins had as much right to share that data as Franklin, and everyone seems to forget Raymond Gosling who actually generated the data.
Sure, but I guess there should have been unanimous consent.

This particular issue is quite complicated. See: https://en.wikipedia.org/wiki/Photo_51

its almost like all modern scinece is team efforts that only the sufficiently tenured get credit for.
This is the really important part. The debates about Franklin, Wilkins, Watson and Crick is like a debate about which A-list movie stars deserve the higher paycheck. Yeah, sure, the hagiography of particular individuals will motivate some people below them to dream big, but it's also demotivating to others who know they'll never be recognized as elite.
As I understand it, that was the real issue with their work from a scientific integrity perspective. Some people speculate that she would have been the third person on the Nobel prize if she were still alive to receive it (Nobels are given only to living contributors).
Nice shout out to your teacher!
didn't pauling think that dna was a triple helix? how this could of worked i have never understood.
yes, triple helix with the phosphates (which are highly charged, and thus repelling each other) at the center!