[HN Gopher] What Rosalind Franklin contributed to the discovery ...
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What Rosalind Franklin contributed to the discovery of DNA's
structure
Author : Feuilles_Mortes
Score : 69 points
Date : 2023-04-25 18:27 UTC (4 hours ago)
(HTM) web link (www.nature.com)
(TXT) w3m dump (www.nature.com)
| jeffreyrogers wrote:
| Rosalind Franklin wrote an obituary for the helix theory.[1] She
| thought her image debunked the helix theory, even though when you
| know the double helix structure of DNA you can very clearly see
| it in the X-ray image.
|
| [1]: https://www.researchgate.net/figure/An-obituary-written-
| by-R...
| maire wrote:
| Here is a 2003 documentary on the same subject.
|
| https://www.pbs.org/wgbh/nova/article/rosalind-franklin-lega...
|
| My take away was that Rosalind Franklin did support the Watson
| Crick paper but that there was some conflict leading up to the
| paper. She did not seem to think her ideas were stolen.
|
| It did not help that after Franklin died - Watson wrote a hit
| piece on Franklin. I think that is what caused people to question
| if Watson was above board while Franklin was alive.
| underlipton wrote:
| I'll be the one to sacrifice my Internet Points by bringing up
| the notion that the question of who discovered DNA's structure is
| not nearly as important as is the question of why the question of
| who discovered DNA's structure is significant. It is, of course,
| primarily and famously the specter of the erasure of women from
| scientifically and socially significant developments, the
| thematic subject that this article addresses.
|
| There is another aspect of this significance, however, in the way
| that James Watson's impropriety - in his work, and in his telling
| of the story of his work - reflects on, and is reflected by, his
| later racist and sexist intellectual misadventures. The myth of a
| singular - well, dual - genius who moves humanity forward lends
| credence to his bigotry - how can the father of genetic science
| be wrong about the influence of genetics on society? - while the
| truth dashes that credibility (without necessarily undoing the
| significance of his actual contributions). And it is a
| controversy that gets re-litigated perennially not because people
| truly care that much about the discovery or discovers, but
| because our understanding of these events underpin beliefs, our
| understanding of the world, that are as sharply relevant today as
| a shard of glass.
|
| To retreat to attempting an exhaustive reconstruction of events
| might be comfortable, but it is also a bit dangerous - it assumes
| a totality of understanding that may be found wanting - and, more
| importantly, it misses the core of why the controversy exists in
| the first place. Peer esteem may be foremost on an academic's
| mind, but we've long left the ivory tower on this one.
| photochemsyn wrote:
| My favorite candidate for 'getting cheated for credit' on the DNA
| discovery is Erwin Chargaff, whose work pointed towards the
| specific base pairing involved. Of course, the arbitrary 3-person
| cutoff for Nobel Prizes is not at all reflective of how science
| is done in practice in terms of the numbers of people involved
| over time in any major discovery:
|
| > "Key conclusions from Erwin Chargaff's work are now known as
| Chargaff's rules. The first and best known achievement was to
| show that in natural DNA the number of guanine units equals the
| number of cytosine units and the number of adenine units equals
| the number of thymine units."
|
| > "The second of Chargaff's rules is that the composition of DNA
| varies from one species to another, in particular in the relative
| amounts of A, G, T, and C bases. Such evidence of molecular
| diversity, which had been presumed absent from DNA, made DNA a
| more credible candidate for the genetic material than protein."
|
| https://en.wikipedia.org/wiki/Erwin_Chargaff#Chargaff's_rule...
|
| Not to distract from Rosalind Franklin's contributions, but if
| anyone is looking for a female role model in molecular biology
| and biochemistry with a major influence and a long career,
| Barbara McClintock is probably at or near the top of that list:
|
| https://www.nature.com/scitable/topicpage/barbara-mcclintock...
| mihaic wrote:
| My favorite anecdote with Chargaff is how he first told Linus
| Pauling about how the ratio between the nucleotide pairs A-T
| and C-G is constant on a sea voyage. Pauling thought he was
| unpleasant and ignored him. It turns out you need to sometimes
| be sociable to stay in the history books.
| slibhb wrote:
| > Lore has it that the decisive insight for the double helix came
| when Watson was shown an X-ray image of DNA taken by Franklin --
| without her permission or knowledge. Known as Photograph 51, this
| image is treated as the philosopher's stone of molecular biology,
| the key to the 'secret of life' (not to mention a Nobel prize).
| In this telling, Franklin, who died of ovarian cancer in 1958 at
| just 37, is portrayed as a brilliant scientist, but one who was
| ultimately unable to decipher what her own data were telling her
| about DNA. She supposedly sat on the image for months without
| realizing its significance, only for Watson to understand it at a
| glance.
|
| I don't think this is what Watson wrote in The Double Helix. He
| wrote that Crick, with his background in math and physics, could
| understand the image produced by Franklin but that he -- Watson
| -- could not.
|
| Watson does write that Franklin thought DNA wasn't helical. The
| linked article provides an interesting explanation for why she
| thought that (at least at one time). As far as I can tell, that
| backs up Watson's narrative rather than undermining it.
|
| One interesting takeaway from The Double Helix was that Watson
| and Crick cracked the problem with guess-and-check model building
| (the article mentions this). Sure, they had some vague idea that
| DNA was a helix and that A-T, C-G relatinoship, but they
| basically played with tinker toys until they got something that
| looked good. Watson claims that they decided on a double helix
| because of his intuition that "in biology, important things occur
| in pairs".
| pazimzadeh wrote:
| > 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
| zinclozenge wrote:
| 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.
| dekhn wrote:
| 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.
| btilly wrote:
| Today, sure. It's famous.
|
| But as https://www.tandfonline.com/doi/pdf/10.1080/1464518031
| 000160... 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.
| zabzonk wrote:
| didn't pauling think that dna was a triple helix? how this
| could of worked i have never understood.
| dekhn wrote:
| yes, triple helix with the phosphates (which are highly
| charged, and thus repelling each other) at the center!
| btilly wrote:
| 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.
| nextos wrote:
| I think the real issue is that her boss shared her data with
| W&C without her permission.
| _Wintermute wrote:
| 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.
| pclmulqdq wrote:
| 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).
| hgsgm wrote:
| Nice shout out to your teacher!
| [deleted]
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