[Music] [Music] [Music] the DNA double helix changed the future in 1953 Francis Crick and James Watson built this chemical model revealing the structure and beauty of DNA to the world in doing so they established DNA as the code for Life DNA changed really everything and that's why that's an icon I mean for me as an icon it's because of its Legacy it was it established a whole field of molecular biology and then MO genetics and it in along the way gathered several Nobel prizes unlike any other chemical model I think that's ever been created that model is personal to you and it's personal to me and the implications for our health and the implications of the health of our relatives and our children it's a very personal reach through and now it's become a a media symbol an art symbol it's it's iconic in its structure yes the making of that model is in itself a wonderful demonstration of success in terms of taking a bit of scientific work done by two very young men one of them postto the other hadn't even finished his PhD and turning their work into something which ultimately the entire scientific world and indeed many people Beyond it were talking about so as a scientist what do you find most interesting about the actual work that Crick and Watson did to make that model happen well there are two things the first of all the actual paper that was published that everyone remembers as having the structure of of DNA in it actually contained n of their own data what they did in producing the model was effectively take five or six pieces of information that other people had put together um and published over the previous five or 10 years and had two or three insights of of their own the inspirational part of Crick and Watson's work was to conceive a double helix structure like a Twisted ladder which explained the X-ray analysis coming from rosn Franklin's and Morris Wilkins Lab at Kings College London there's been a lot of discussion about what was the role of rosn Franklin because Crick and Watson both got the Nobel Prize and so did Morris Wilkins who got uh the X-ray crystallography going and the X-ray crystallography caused created the data but rosin Franklin had died by the time of the Nobel Prize but it's often been discussion that she a woman was somehow uh biased against what do you think her role is from a purely technical point of view the DNA molecules that she was working on in the lab come in different forms and she was much more sold on looking at one form than another form and of course it was the one she was almost less interested in the beta form which was the one that excited Crick and Watson I don't think we'll ever know because we've effectively only really got Watson's side of the story and he's rather dismissive of of Ros in Franklin I mean she was actually very highly regarded in her lifetime wasn't she absolutely published some stunning papers and and and as a technician in terms of obtaining some of the best crystals of DNA I think she was probably the the leader in the world and of course we see that in the fact that that data was so clean that Crick and Watson instantly recognized the significance of it it confirmed to them it had to be a helix now other people had suggested a helix but this confirmed it to them this structure showed how the molecule could divide its cell division and ensure the production of two identical copies it also suggested how the rungs of the double helix's ladder are made of pairs of chemical bases so with that geometry you have to say how can you put together the A's the t's the C's and the G's in a way that fits together and what they did was was uh two insights the first Insight was that actually it was a particular chemical form of the these bases they would only fit in the Helix when a was opposite of T and G was opposite of c and what that meant was that you had effectively a unique way of lining up across a helical molecule and the second Insight they had was that the backbone molecule actually don't run in parallel they run the opposite it way around so it's like two ways of of a dual Carriage Way one strand goes one way and the other strand goes the other way but of course it's it's the implications of this structure of having these two strands that really was was tantalizingly uh teased at the end of the the very first paper where they say it hasn't escaped our notice that this provides a mechanism for copying which alluded to the second paper which came along only a few months later wherein they really explained the detail of of what underpinned the model and that is the beautiful Simplicity of DNA is the fact that you can go from one molecule to two identical molecules that are copies which of course we know in in all of biology one cell divides into two so one to two is the perfect um it's it's the explanation behind so in the structure of it you have the whole process of reproduction absolutely the whole simplicity of of life itself is is in is in that chemical structure