Friedrich Miescher discovered DNA in 1869, a century before Watson and Crick | Hacker News Reader

Friedrich Miescher discovered DNA in 1869, a century before Watson and Crick

pubmed.ncbi.nlm.nih.gov

54 pointsJPLeRouzic23 comments

The title of the linked article is "Before Watson and Crick in 1953 Came Friedrich Miescher in 1869". This is technically correct, though misleading - Miescher did in fact chronologically precede Watson and Crick.

The title of this HN post is "Friedrich Miescher discovered DNA in 1869, a century before Watson and Crick". The difference turns this title into one that is definitely false, since it clearly implies that Miescher did what Watson and Crick did, long before they did it. That's not true.

Watson and Crick did not discover the existence of DNA. They discovered the structure of DNA. The existence of DNA was already well known, and other groups were also trying to discover its structure.

The issue is mainly that in many people's minds, W&C "discovered DNA".

I studied DNA extensively in my PhD program and didn't even know about Miescher until I read https://en.wikipedia.org/wiki/The_Growth_of_Biological_Thoug... and even then it's just sort of a little chapter at the end of the book.

The problem here is that the HN title is clickbaity and inaccurate where the NIH title is correct. On HN we try to avoid this kind of thing and I'm betting Dang will come in and change the title.

Watson and Crick did not get the noble prize for discovering the chemical nature of DNA, nor for being the first to suggest it might be the material of heredity, nor for identifying it as a double helix...

They got it for showing how DNA arranged as an anti-parallel two stranded base-paired helix could be copied from generation to generation, thus showing how it could be the material of heredity. Their original paper contains just one drawing of such a helix, and no experimental data.

"...nor for identifying it as a double helix..."

I think you're wrong about this part. Maybe someone else had speculated that it might be a double helix (I don't know), but to take such a speculation seriously one has to work out the details, and see that they are compatible with the X-ray crystallography data.

Rosalind Franklin and Ray Gosling figured out it was a double helix. Pauling was speculating it was a triple helix. They published their finding in the same edition of Nature as Watson and Crick published their model.

Watson and Crick's paper contains the sentence "The novel feature of the structure is the manner in which the two chains are held together by the purine and pyrimidine bases."

Perhaps this claim to novelty is incorrect - I certainly don't know enough about the history to have an independent opinion - but I think one must take the conventional view to be that Watson and Crick did indeed discover the structure of DNA.

The conventional view is unfortunately incorrect. They proposed an (almost) correct view of how the nucleotides were arranged into a helix. Their proposal included the feature that each strand of the double helix was in fact a "mirror image" of the other, thus could be divided and copied to yield two identical copies for inheritance by two cells.

The actual atomic structure of DNA was not experimentally determined until much later.

I don't think they ever said that it was a true mirror image, just that it was two antiparallel strands.

The original Watson and Crick model was almost perfecftly correct even without the need for explicit 3D crystal structure, the major problem being that the water content of the fiber used in the study was wrong, so they made a model of A-DNA structure, rather than B-DNA structure. If you look down the axis of the double helix in the W&C structure, there is significant free space in the interior because of the way the bases have moved, where in B-DNA, the itnerior is packed with tightly stacked bases.

[edit: I had forgotten that the original W&C paper says there are only two H-bonds between G and C rather than 3, which is another detail of the structure which was not completely correct.]

The original W&C model did not postulate three H-bonds between G and C, but two, which is one of the reasons why it is only "almost" correct.

Good point, I updated my comment to reflect that. Here's a nice writeup: https://www.nature.com/articles/439539a

Thanks! That was interesting.

Nobody proposed or suggested the idea underlying that sentence other than W&C; it was their illumination. They did stumble for a while until external folks corrected some of their misunderstandings (specifically, which of the keto-enol forms of the bases were expected at physiological condition)

I believe Franklin only identified the structure as being helical (if you look at the fiber diffraction images, that "X" shape is indicative of helicity) and that the phosphates were on the outside, but not that it was a double helix, nor that the strands were antiparallel, or the specific structure of the base pairs (all of which were the key insights made by W&C).

I think you are correct. The observation that was apparently key to W&C modelling the structure correctly was that the phosphates were on the outside of the helix.

In my view of the history of this discovery, this would possibly be the only thing "stolen" from Rosalind Franklin by W&C.

Nevertheless, despite the rhetoric that often surrounds this issue, it is worth noting

0) that Franklin was dead at the time the relevant Nobels were awarded, and they are not awarded posthumously;

1) the Nobel W&C received was actually awarded to three people, the third being Wilkins, who was a co-investigator with Franklin.

Actually, phosphates on the outside were actually part of Furberg's model from '52 - see Model I in http://actachemscand.org/pdf/acta_vol_06_p0634-0640.pdf which W&C specifically mention in their paper.

I personally agree about Franklin and the Nobel- I think most people just read Dark Lady and believe its conclusion. I always recommend that people read Eighth Day of Creation, which presents a very compelling alternate view based on primary data.

Sorry for the potato quality, but here are the reports by both Watson and Crick as well as Rosalind Franklin. One directly follows the other.

https://i.imgur.com/f423vS5.jpg https://i.imgur.com/84fdLlp.jpg

Great article. A snippet from the conclusion that I found particularly interesting: "History of science all too often highlights "superstar" scientists who have illustrious careers, overcoming great obstacles and resistance to new ideas, leading to a public vindication, sometimes followed by a Nobel Prize. Miescher’s story is different. There was no immediate recognition nor ultimate vindication in his case, yet his discovery proved fundamental for the whole of modern biology. Excavating stories such as his from the past, and incorporating them into the history of genetics, helps us portray the process of science more realistically."

The writeup in Mayr's book "The Growth of Biological Thought" is really enjoyable. Miescher started by working with pus collected from hospital patients, but quickly moved to Rhine salmon "because their sperm is filled with the substance". His work was so surprising that his advisor Hoppe-Seylor (a well-known biologist for many other things) redid all his experiments. It's actually one of the great examples of protein bias- they couldn't understand why the molecule they purified didn't contain sulfur (DNA doesnt' have sulfur, while many proteins do).

The problem is now the superstardom narrative has grown in importance in academics, regardless of validity. It's not just something we project into the past anymore, it's something that is needed to project into the future, to survive at the most basic levels. Everyone is the next W&C (ignoring the complexity of the truth around that narrative), until they have tenure or are pushed out altogether. In this way false narratives about the past become impossible goals for the future, which leads to false claims in the present.

being in academia myself, this hits home so hard :/ the field picks some rockstars, which imv is to a good extent based on charisma, and then goes with that.

one of 'our' rockstars has pushed a certain hypothesis for more than 10 years. it is plausible on a conceptual level, but I have yet to see systematic, large-scale evidence for it. it would not be entirely trivial, but also not that hard to test.

here is what happened: that person has fallen from grace due to some troublesome accusations. those accusations did not stick up in court btw. the case was made public 2017, the court case was closed this year. still that person's reputation is tarnished, so is their rockstar aura.

here comes the kicker: just this year, the first study comes out, presenting results that that hypothesis does not hold up, certainly in some contexts. i know for a fact that at least one more team has had similar results a few years ago - but when they first presented the results informally, they felt pressured to shelf the project.

I'm not sure how much my cynicism is just me or my immediate experiences over the years, but I don't really trust the academic system anymore in terms of credit or even as much in terms of validity. Or rather I do, but in some abstract sense, in that if I see a meta-analysis with some mechanism of dealing with publication bias (formal modeling of bias, or preregistration) I might believe something, but I don't attach any credit to the body of work beyond those who as a group in toto were involved in it.

Too much credit is given to trappings of progress or something of that sort; conversely, people are punished too much for things that are irrelevant, and both seem to be weighted capriciously.

I see similar viewpoints expressed repeatedly in various outlets, but little seems to change.

Shows the importance of communication.

If you discover something, but only you know, and you never tell anyone, is it really a discovery for society? (no)

We celebrate society-wide discoveries, because it’s impossible to keep track of hidden discoveries. (e.g. Columbus, Edison, etc.)

Reply on news.ycombinator.com