[HN Gopher] What Rosalind Franklin contributed to the discovery ... ___________________________________________________________________ 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] ___________________________________________________________________ (page generated 2023-04-25 23:00 UTC)