WEBVTT - How DNA Computers Work 0:00:02.400 --> 0:00:05.400 Get in touch with technology with tech Stuff from how 0:00:05.440 --> 0:00:14.360 stuff works dot com. Hello everyone, and welcome to tech stuff. 0:00:14.360 --> 0:00:16.000 My name is Chris Poulette and I am an editor 0:00:16.079 --> 0:00:18.799 at how stuff works dot com. Sitting across from me, 0:00:19.040 --> 0:00:22.880 as he typically does on these days, is senior writer 0:00:23.000 --> 0:00:27.600 Jonathan Strickland. He there. Yeah, so we were we were 0:00:27.640 --> 0:00:30.520 going to share some twisted logic with you today. Yes, 0:00:30.680 --> 0:00:37.720 we wanted to talk about dioxy ribonucleic acid computers. DONA 0:00:38.360 --> 0:00:43.680 is the DONA No, no no, the DONA NA d n 0:00:43.760 --> 0:00:48.360 A computers And what is a DNA computer? What would 0:00:48.360 --> 0:00:51.559 it be? Because we're really in the very early stages 0:00:51.680 --> 0:00:56.400 of using DNA for the reasons of uh purposes of 0:00:56.400 --> 0:00:59.880 a computer. But what would a DNA computer be? Why 0:01:00.040 --> 0:01:03.080 would we even use DNA? And what the heck is 0:01:03.120 --> 0:01:06.160 this DNA stuff? Anyway, Well, you know, I've got a 0:01:06.280 --> 0:01:10.920 USB port in the back of my head. So yeah. 0:01:10.959 --> 0:01:12.760 He also woke up one day and he was in 0:01:12.760 --> 0:01:16.360 a giant battery and he had to get down. Turns 0:01:16.360 --> 0:01:20.480 out Chris is the one, and definitely we got but this, 0:01:21.240 --> 0:01:23.600 you know, we got agents Smith showing up every other 0:01:23.680 --> 0:01:26.080 day at the office and we're like, he's not here, 0:01:26.120 --> 0:01:30.200 today's teleworking and us just irritating. But anyways, in the 0:01:30.240 --> 0:01:36.800 matrix DNA, so DNA is is is important stuff. I mean, 0:01:36.800 --> 0:01:42.800 this is a molecule that contains information that you know, collectively, 0:01:42.880 --> 0:01:48.280 this information makes makes organisms what they are. Yes, and 0:01:48.560 --> 0:01:54.000 uh and so biologically DNA is used to store information 0:01:54.640 --> 0:01:58.480 and that is really the key there, you know, saying, 0:01:58.760 --> 0:02:02.240 wait a minute, if DNA stores information for organisms, could 0:02:02.320 --> 0:02:06.600 we use DNA to store information for other purposes? But 0:02:06.960 --> 0:02:10.919 to to really explain this, DNA, it's this, it's it's 0:02:10.960 --> 0:02:16.639 that double helix molecule. You're probcing, Uh, you know, illustrations 0:02:16.639 --> 0:02:18.240 of it. You may have built a model of it. 0:02:18.680 --> 0:02:21.240 If you are in school, you may be studying this 0:02:21.400 --> 0:02:24.320 so much that the terms I'm going to use you're thinking, wow, 0:02:24.480 --> 0:02:27.880 he's really glossing over this. But it's because this is 0:02:27.960 --> 0:02:30.120 tech stuff, not stuff to blow your mind. So we're 0:02:30.160 --> 0:02:32.640 not going to go too deep into the cellular biology 0:02:32.720 --> 0:02:35.440 aspect of DNA. Yes, And if you're looking for your 0:02:35.440 --> 0:02:37.880 mind being blown, I'm sorry you've come to the wrong place. 0:02:38.000 --> 0:02:41.200 Right now, DNA has a has a lot of instructions 0:02:41.200 --> 0:02:43.760 in it. Yes, As it turns out, it's a very 0:02:43.800 --> 0:02:48.440 tiny molecule with UH, with a very large capacity for 0:02:48.440 --> 0:02:51.360 for carrying information. Yeah, if you were to actually stretch 0:02:51.400 --> 0:02:55.120 out a DNA molecule and lay it lengthwise, it would 0:02:55.320 --> 0:02:57.799 end up taking much more space than it typically does 0:02:57.840 --> 0:03:03.119 because it has this twisted three dimensional uh uh structure. 0:03:03.560 --> 0:03:06.880 Hence my earlier dumb joke. Right, So this twisted structure 0:03:06.880 --> 0:03:13.240 actually allows this this very dense UH storage medium to 0:03:13.880 --> 0:03:18.640 exist in a relatively small volume of space. Yeah, because 0:03:18.639 --> 0:03:21.079 you've twisted it. And you know, it's the whole thing 0:03:21.120 --> 0:03:25.200 about UH conserving surface area and all that great stuff 0:03:25.240 --> 0:03:27.400 that all my biologist friends go on and on and 0:03:27.440 --> 0:03:31.200 on about and then I end up wandering away. Um. 0:03:31.680 --> 0:03:38.800 But DNA has UH among many other attributes. There are 0:03:39.280 --> 0:03:44.880 pairs of bases that that pair up in DNA, and 0:03:44.960 --> 0:03:47.600 this is you know, the the structure of those The 0:03:47.760 --> 0:03:52.400 sequence of those determines what information is stored in that 0:03:52.480 --> 0:03:56.160 strand of DNA. Okay, So those four bases you have 0:03:56.280 --> 0:04:02.480 at Anne, Citazine, Guani, and thyming and usually we just 0:04:02.640 --> 0:04:07.280 call those A, C, G and T. And the way 0:04:07.360 --> 0:04:10.560 that those are sequenced, like I said, within a strand 0:04:10.600 --> 0:04:15.080 of DNA determines the type of information that that DNA holds. 0:04:16.200 --> 0:04:21.840 Uh and uh, it's it's it's that that forms the 0:04:21.920 --> 0:04:26.159 basis of the idea of using a DNA computer because 0:04:26.800 --> 0:04:30.520 in our of course, in our our classic computer model, 0:04:31.200 --> 0:04:37.320 we've got computers thinking quote unquote thinking in binary right, 0:04:38.320 --> 0:04:43.840 zeros and ones and so uh. With using DNA. UH, 0:04:44.160 --> 0:04:48.920 the approach right now is to associate certain of those 0:04:49.000 --> 0:04:53.840 bases with zeros and the others with ones, and the 0:04:53.920 --> 0:04:57.360 idea being that way you could sequence a DNA down 0:04:57.440 --> 0:05:00.800 the length of a strand of DNA with these zeros 0:05:00.839 --> 0:05:04.120 and ones. You encode a strand of DNA that way, 0:05:04.560 --> 0:05:06.720 and then you would decode it. You would read back 0:05:07.160 --> 0:05:11.520 those those base pairings and that would determine whether each 0:05:11.600 --> 0:05:15.240 pair was a zero or a one, and then you 0:05:15.279 --> 0:05:19.000 would decode that into binary language, and thus you would 0:05:19.560 --> 0:05:25.200 get back to whatever information you originally stored onto the DNA. UM. 0:05:26.360 --> 0:05:28.680 This is it makes it sound pretty simple, but this 0:05:28.839 --> 0:05:32.440 is high tech science stuff right now. Now. Granted, it's 0:05:32.520 --> 0:05:36.360 high tech science stuff that we have made huge advances 0:05:36.400 --> 0:05:41.320 in over the last two decades. Really, so things that 0:05:41.520 --> 0:05:46.960 were seen as practically impossible two decades ago are things 0:05:47.040 --> 0:05:50.920 that we do almost not quite routinely, but with a 0:05:51.000 --> 0:05:54.080 greater ease than we could have expected. Yeah, but over 0:05:54.200 --> 0:05:59.080 the course of of the last few decades. Um, it's 0:05:59.120 --> 0:06:02.120 the kind of thing that when people see the double helix, 0:06:02.279 --> 0:06:06.159 it's familiar. Um, you know, it's it's it's it's high 0:06:06.200 --> 0:06:09.600 tech science. But it's in our public consciousness too, it's 0:06:09.640 --> 0:06:13.120 in our DNA. There you go the fact that that 0:06:13.400 --> 0:06:16.960 that's a a uh slang term, you know, for something. 0:06:17.000 --> 0:06:19.080 When you say it's, it's basically you're saying it's deeply 0:06:19.320 --> 0:06:22.840 ingrained in your personality or whatever you're saying that about. Um, 0:06:23.360 --> 0:06:25.960 you know, it's it's certainly something that that we're all 0:06:26.000 --> 0:06:28.720 familiar with now, but only a few decades ago, you know, 0:06:28.920 --> 0:06:33.640 it was completely foreign to us. Yeah. So yeah, let's 0:06:34.040 --> 0:06:36.440 we'll do a quick, quick rundown of the history of 0:06:36.640 --> 0:06:40.960 our knowledge about DNA, because clearly DNA has existed for 0:06:42.040 --> 0:06:44.560 millions of years, but we've only really been aware of 0:06:44.680 --> 0:06:49.200 it since about well, we knew something about it back 0:06:49.240 --> 0:06:55.840 in eighteen sixty. Yes, when Freedrich Meischer, who was thank 0:06:55.880 --> 0:07:00.160 you was he was a biologist from Switzerland and he 0:07:01.080 --> 0:07:06.000 was looking at something pretty darn gross. He was looking 0:07:06.040 --> 0:07:10.200 at bandages that had pus on them, and he isolated 0:07:10.280 --> 0:07:13.600 DNA from the pus on the bandages, and he thought 0:07:13.920 --> 0:07:20.040 that perhaps the this stuff that these nucleic acids, which 0:07:20.120 --> 0:07:24.800 is DNA, is a nucleic acid. He thought that perhaps 0:07:25.000 --> 0:07:30.600 this stuff might contain information in it that would determine 0:07:30.760 --> 0:07:34.560 why stuff is the way it is so genetic information. 0:07:34.680 --> 0:07:38.480 He thought that that probably did contain that information, but 0:07:38.520 --> 0:07:40.920 there was no way for him to be able to 0:07:41.160 --> 0:07:45.280 confirm it. He could not point to anything and say, see, 0:07:45.680 --> 0:07:49.560 I'm right, So that had to wait for future scientists 0:07:49.640 --> 0:07:53.240 to uh, to really dive into it, not not the 0:07:53.320 --> 0:07:56.120 pus that big gross, but to really dive into the 0:07:56.200 --> 0:07:59.600 information and study it and and figure out more details. 0:07:59.640 --> 0:08:06.280 So Intree, some scientists at Rockefeller University, including Oswald Avery, 0:08:07.120 --> 0:08:11.680 showed that DNA taken from a bacterium could make a 0:08:12.200 --> 0:08:18.440 non infectious type of bacteria become infectious bacteria. So the 0:08:19.360 --> 0:08:22.600 thought was that there must be some information from this 0:08:23.200 --> 0:08:27.120 nucleic acid taken from one type of bacteria that could 0:08:27.440 --> 0:08:31.920 transfer properties to a different bacteria that otherwise would not 0:08:32.120 --> 0:08:37.440 have that infectious property. But what does it? Yes, that's 0:08:37.480 --> 0:08:41.079 kind of what everyone was saying. Well, there's some sort 0:08:41.160 --> 0:08:46.040 of information holding material here. We don't really understand the 0:08:46.200 --> 0:08:49.439 mechanism by which it stores information, nor how does it 0:08:49.559 --> 0:08:54.000 impart that information or or replicated. We didn't know that 0:08:54.200 --> 0:08:57.880 at the time. Uh. And then in nineteen fifty two, 0:08:58.360 --> 0:09:03.120 Alfred Hershey and Martha Chase showed that to make new 0:09:03.240 --> 0:09:08.880 viruses bacteria fage virus injected DNA into the host cell, 0:09:09.559 --> 0:09:12.600 which was important because previously it was thought that perhaps 0:09:12.679 --> 0:09:16.560 it was through protein exchange, but instead of protein exchange, 0:09:16.600 --> 0:09:21.600 it was DNA exchange. So that showed, yes, there's something 0:09:21.720 --> 0:09:25.000 in this. This d N A is what is important. 0:09:25.360 --> 0:09:30.000 And then came along Watson and Crick, Yes, James D. 0:09:30.120 --> 0:09:35.720 Watson and Francis Crick. Yeah. They it was clear that, uh, 0:09:36.400 --> 0:09:39.120 that people were already onto something. Hershey and Chase had 0:09:39.200 --> 0:09:42.120 something there. And it was only a year later when 0:09:42.520 --> 0:09:46.960 Watson and Crick, uh you know, made their announcement they 0:09:47.040 --> 0:09:50.280 had discovered the structure of DNA, right, and so this 0:09:50.440 --> 0:09:54.640 is when we started to really learn what how DNA 0:09:55.280 --> 0:10:00.160 you know, forums and what shape it takes and why 0:10:00.280 --> 0:10:05.320 that's important. And um so once all of that was taken, 0:10:06.040 --> 0:10:08.000 once we learned all that, we began to see that 0:10:08.120 --> 0:10:10.599 these base pairings I was talking about, we learned that 0:10:10.679 --> 0:10:13.600 they pair in very specific ways. You know, I mentioned 0:10:13.640 --> 0:10:18.800 there are the four different bases. There's A, the A, C, G, T. Well, 0:10:19.679 --> 0:10:25.400 half of those A and G are called purines. Uh, 0:10:25.559 --> 0:10:31.480 C and T are uh perimidines. I'm glad you took 0:10:31.559 --> 0:10:34.480 that part. Yeah me too, Uh, you know, way back 0:10:34.520 --> 0:10:36.559 when I was actually really good at biology. But man, 0:10:36.679 --> 0:10:41.000 that was a few decades ago. So anyway of perings 0:10:41.000 --> 0:10:44.920 and peri peri pyrimidines. Look, I can't even do it now, 0:10:45.400 --> 0:10:51.080 periings of paramidines. Still glad you took that bond together, right, So, uh, 0:10:51.600 --> 0:10:54.400 you don't get too purines bonding together, and don't get 0:10:54.440 --> 0:10:58.840 two pyramidines bonding together. And to be even more specific, 0:10:59.720 --> 0:11:03.040 A and T will bond together, and C and G 0:11:03.600 --> 0:11:07.160 will bond together. All right, So that that means that 0:11:07.240 --> 0:11:09.880 you know, you can't you're not going to get a 0:11:10.000 --> 0:11:13.520 strand of DNA where A and C or A and 0:11:13.679 --> 0:11:18.640 G are paired together. It does not happen. They structurally, 0:11:18.720 --> 0:11:25.520 that doesn't happen. So uh that also dictates the rationale 0:11:25.600 --> 0:11:30.320 behind using uh these pairings as zeros and ones because 0:11:30.360 --> 0:11:33.679 you can either have UH. You can either have the 0:11:33.800 --> 0:11:37.040 A T pairing or the C G pairing, right, so 0:11:37.200 --> 0:11:40.079 that that lets you say, okay, well that's binary. It's 0:11:40.120 --> 0:11:43.600 either you you just designate that one means one, pairing 0:11:43.679 --> 0:11:46.920 means zero, the other pairing means one. Um, if it 0:11:47.040 --> 0:11:52.280 weren't that case, if we could have multiple pairing, multiple uh, 0:11:53.880 --> 0:11:56.360 like like if A could pair with G instead of 0:11:56.440 --> 0:11:59.240 just A and T, then you would say, all right, well, 0:11:59.280 --> 0:12:03.520 now we've got system that goes beyond binary, which in theory, 0:12:04.000 --> 0:12:09.400 if you completely change the way computers work, would mean 0:12:09.480 --> 0:12:15.400 that you could dramatically increase parallel processing because you could 0:12:15.520 --> 0:12:18.360 designate things. It would almost be like the cubits of 0:12:18.400 --> 0:12:23.439 a quantum computer, where you know, the basic explanation is 0:12:23.480 --> 0:12:26.800 a cubit represents both a zero and a one and 0:12:26.960 --> 0:12:31.360 all values in between in superposition of one another, and 0:12:31.640 --> 0:12:35.599 that if you have enough cubits you can perform a 0:12:35.800 --> 0:12:41.880 massive parallel processing problem all at the same time because 0:12:42.320 --> 0:12:46.120 those that that one group of cubits is behaving as 0:12:46.160 --> 0:12:51.880 if it's uh, you know a huge number of traditional bits. 0:12:53.040 --> 0:12:55.120 I think it's important to remember too that no matter 0:12:55.200 --> 0:12:59.640 how many bases DNA has they all belong to us. 0:13:00.000 --> 0:13:02.600 I knew it. I knew it. I was like, oh, 0:13:02.720 --> 0:13:04.040 I was going to do an all your base I 0:13:04.160 --> 0:13:06.280 belonged to us. If someone set us up the bomb 0:13:07.200 --> 0:13:10.000 so well, it could be Actually, if you if you 0:13:10.640 --> 0:13:14.079 were trying to if those pairs become corrupted, they will 0:13:14.160 --> 0:13:18.160 not work and uh and a cell can die. Actually, 0:13:18.160 --> 0:13:20.240 we're getting a lot of this information to from our 0:13:20.320 --> 0:13:22.800 our excellent article on how stuff works dot com about 0:13:22.880 --> 0:13:26.360 how DNA works. It gets into a whole lot more detailed, right, Yeah, 0:13:26.360 --> 0:13:28.360 if you want to learn more about and and it's 0:13:28.480 --> 0:13:30.760 very accessible. It's a very accessible article. So if you're 0:13:30.800 --> 0:13:32.800 curious about you know, you've always heard about d N 0:13:32.880 --> 0:13:34.920 A and you've heard about DNA testing, and you know 0:13:35.040 --> 0:13:38.920 about chromosomes and genes, but you're not really you know, 0:13:39.800 --> 0:13:42.480 beyond that, you're kind of confused. I highly recommend you 0:13:42.559 --> 0:13:44.640 read how DNA works at how stuff works dot com. 0:13:45.480 --> 0:13:47.760 We also have an article on how DNA computers work, 0:13:48.040 --> 0:13:52.360 which is pretty interesting because it's talking about an earlier 0:13:52.480 --> 0:13:56.720 era of DNA computers, but recent developments have really brought 0:13:56.800 --> 0:14:01.920 it brought to lights some interesting uh, new technologies and 0:14:02.080 --> 0:14:05.360 new use cases for d N a and we'll get 0:14:05.400 --> 0:14:07.520 into those in a second. It's it's funny that you 0:14:07.600 --> 0:14:10.120 say that, because I'm sure that people this is futuristic 0:14:10.320 --> 0:14:12.880 enough where people are saying, what are you talking about 0:14:12.960 --> 0:14:15.160 new developments? We haven't heard of a d N A 0:14:15.280 --> 0:14:18.439 computer before? But yeah, that's that's not really surprising. This 0:14:18.559 --> 0:14:20.920 is the kind of thing, like like quantum computing, where 0:14:21.280 --> 0:14:23.080 they've been working on it for some time, but it's 0:14:23.120 --> 0:14:25.920 not at a point where they can really you know, 0:14:25.960 --> 0:14:28.040 put something on a shelf and go look at this. Yeah, 0:14:28.920 --> 0:14:31.240 where people really take notice of it. In general, this 0:14:31.400 --> 0:14:34.960 is all stuff that's taking place in universities and research facilities, 0:14:35.120 --> 0:14:37.960 and it's you know, most of these machines that are 0:14:38.000 --> 0:14:41.440 being made now or or these implementations of using DNA 0:14:41.600 --> 0:14:46.600 for information digital information are really in the prototype stage. 0:14:46.880 --> 0:14:50.640 But we're getting the technology that allows us to create 0:14:50.760 --> 0:14:54.840 these machines is becoming more and more sophisticated and less expensive, 0:14:55.240 --> 0:14:59.480 which of course is key. It's huge any new Gordon 0:14:59.560 --> 0:15:02.920 Moore explained that back in and when he did his 0:15:03.160 --> 0:15:06.000 his paper about cramming more components onto an integrated circuit. 0:15:06.680 --> 0:15:09.200 His point was not just that technology was advancing to 0:15:09.280 --> 0:15:11.960 a point where we could shrink stuff down and fit 0:15:12.120 --> 0:15:15.600 twice as many components onto a square inch of silicon 0:15:15.680 --> 0:15:17.760 as we could a year ago. It was also that 0:15:17.800 --> 0:15:21.160 the manufacturing process was becoming efficient enough and cheap enough 0:15:21.200 --> 0:15:26.080 where that made sense. So same sort of thing here. Well, 0:15:27.040 --> 0:15:30.440 all right, so we've we've determined that DNA contains information. 0:15:30.720 --> 0:15:33.560 It because of its very structure, it can contain a 0:15:33.680 --> 0:15:36.840 lot of information in a small volume. Uh. And then 0:15:37.000 --> 0:15:40.520 it wasn't until about nine four, and I remember it 0:15:40.600 --> 0:15:42.760 was the it was the fifties, the early fifties when 0:15:42.760 --> 0:15:45.040 we started to really understand what DNA was and how 0:15:45.360 --> 0:15:48.800 how it formed and how and its structured and everything 0:15:48.880 --> 0:15:52.720 like that. In ninety four, a man named Leonard Edelman 0:15:53.680 --> 0:15:56.320 came up with this idea. He sort of, uh introduced 0:15:56.360 --> 0:16:02.200 the idea of using DNA to solve math problems. And 0:16:02.640 --> 0:16:07.040 it was essentially this idea of coding DNA as if 0:16:07.120 --> 0:16:12.680 it were a strip of binary code. And so he 0:16:14.000 --> 0:16:16.480 took this idea and he sort of ran with it. 0:16:16.600 --> 0:16:19.600 He began to formulate an idea about how to how 0:16:19.680 --> 0:16:23.320 to create an experiment that could show that this would work. 0:16:23.480 --> 0:16:27.040 And it's funny because it's talking about a DNA computer. 0:16:27.200 --> 0:16:29.840 But if you read about the experiment, it sounds more 0:16:30.000 --> 0:16:35.080 like someone in a chemistry lab mixing various chemical compositions 0:16:35.160 --> 0:16:39.440 together and then coming up with a solution at the 0:16:39.560 --> 0:16:42.240 end of it. And that's it turns out that this 0:16:42.400 --> 0:16:46.880 is a computational solution, not just a chemical solution. I 0:16:47.200 --> 0:16:49.800 see what you did there, little word play there. Yeah, 0:16:49.800 --> 0:16:53.840 it's a little a little incredible. So he yeah, he um, 0:16:54.840 --> 0:16:59.280 dissolved my objections. So wait, let me read. I'll read 0:16:59.360 --> 0:17:02.440 the steps from our article on DNA computers, because I 0:17:02.520 --> 0:17:05.840 want to explain how this early early early implementation of 0:17:05.920 --> 0:17:09.200 a DNA computer, how it how it played out, and 0:17:09.280 --> 0:17:13.639 it's kind of amazing. All right. Here are the steps. 0:17:14.040 --> 0:17:17.679 Number one strands of DNA represent the seven cities. Now 0:17:17.840 --> 0:17:19.600 when it says seven cities in here, what he was 0:17:19.680 --> 0:17:21.480 doing was he was trying to solve something called the 0:17:21.560 --> 0:17:26.480 traveling salesman problem, also the directed Hamilton's path problem. The 0:17:26.600 --> 0:17:29.399 idea being that you're supposed to find the shortest route 0:17:29.480 --> 0:17:32.680 between a group of cities, and and it could be 0:17:33.320 --> 0:17:35.760 any number really of cities, but you have to only 0:17:35.880 --> 0:17:39.520 go through each city one time. Um, and it becomes 0:17:39.600 --> 0:17:41.880 more complex. This is this is why this is such 0:17:41.920 --> 0:17:44.920 a fascinating problem. Uh As Jonathan pointed out to me 0:17:45.119 --> 0:17:47.560 right before, he reminded me that this is something that 0:17:47.760 --> 0:17:51.440 quantum computing is fascinated with because this is such a 0:17:51.960 --> 0:17:54.520 I don't know what you call it, thorny, a thorny problem. 0:17:54.760 --> 0:17:57.080 So it was that problem that they were were that 0:17:57.280 --> 0:17:59.480 he wanted to work on, and he chose, I believe 0:17:59.720 --> 0:18:02.680 seven in cities, he said that as his benchmark I 0:18:02.720 --> 0:18:04.359 wanted to do. And see, this is this is an 0:18:04.400 --> 0:18:07.399 interesting problem for h in computers because think about it, 0:18:07.480 --> 0:18:10.560 You've got seven cities. You can only travel through each 0:18:10.640 --> 0:18:13.320 city once. You have to find the most efficient pathway 0:18:13.400 --> 0:18:15.720 to go. Well, the way a computer would do this, 0:18:16.440 --> 0:18:21.200 generally speaking, is to start going through every single possible 0:18:22.200 --> 0:18:27.200 um permutation of that trip, going from city to city, 0:18:27.560 --> 0:18:29.639 and determining which of those is the most efficient by 0:18:29.680 --> 0:18:31.680 the end of it by comparing them all, which can 0:18:31.800 --> 0:18:35.600 take ages and as as of course, as you add 0:18:35.640 --> 0:18:38.800 more cities, as you add complexity to the problem, it 0:18:39.040 --> 0:18:43.600 creates an exponentially more difficult problem for the computer to solve. 0:18:43.960 --> 0:18:46.280 You know, I don't think it's that unlike trying to 0:18:46.359 --> 0:18:49.720 crack a password. In the in the you know, other 0:18:49.800 --> 0:18:52.800 references we've made to these again, parallel processing. That's another 0:18:52.840 --> 0:18:56.160 reason why quantum computers are very scary for anyone who's 0:18:56.160 --> 0:18:59.920 in cryptography who wants to create good encryption, because they're 0:19:00.119 --> 0:19:03.280 about using parallel processing to attack, you know, do a 0:19:03.320 --> 0:19:08.439 brute force attack on a password. You can really reduce 0:19:08.520 --> 0:19:10.480 the amount of time it would take you to crack 0:19:11.040 --> 0:19:13.359 a password, like a password that would probably take you 0:19:13.520 --> 0:19:17.400 thousands of years in classic computer time might only take 0:19:17.880 --> 0:19:20.919 an hour in using a quantum computer because it's using 0:19:20.960 --> 0:19:24.560 that parallel approach. So just remember, quantum computing is the 0:19:24.680 --> 0:19:28.560 cure for the common code. Man, what is it with 0:19:28.640 --> 0:19:33.879 you today? Chris is in a mood folks anyway, Alright, 0:19:33.920 --> 0:19:36.040 so like getting back to getting back to this thing, 0:19:36.520 --> 0:19:40.560 this this set of steps, all right. So Aedelman creates 0:19:40.600 --> 0:19:44.920 strands of DNA that represent the seven cities. Uh, and 0:19:45.160 --> 0:19:50.680 so it's these A, T, and CG pairings and then um, 0:19:51.359 --> 0:19:55.000 these various sequences represent each city and possible flight path. 0:19:55.760 --> 0:19:59.960 He then took the molecules that these strands of DNA 0:20:00.040 --> 0:20:03.119 A and mixed them in a test tube, and some 0:20:03.280 --> 0:20:05.560 of the strands of DNA stuck together in a chain 0:20:05.640 --> 0:20:09.840 of those strands represented a potential answer to that question, 0:20:10.840 --> 0:20:13.440 which of these you know, which route is the most efficient. 0:20:14.320 --> 0:20:17.119 Within a few seconds, all of the possible combinations of 0:20:17.200 --> 0:20:20.479 DNA strands were created in the test tube, and then 0:20:20.640 --> 0:20:24.440 Edelman eliminated the wrong molecules through chemical reactions, which left 0:20:24.480 --> 0:20:27.520 behind only the flight paths that connect all seven cities. 0:20:28.400 --> 0:20:34.199 So here he was doing chemistry and looking at molecules 0:20:34.320 --> 0:20:39.119 by uh it was and it was biological chemistry because 0:20:39.200 --> 0:20:44.879 he was using organic DNA um and and trying to 0:20:44.960 --> 0:20:46.560 come up with the answer that way, which is pretty 0:20:46.560 --> 0:20:48.639 interesting to me. I mean, it looks that sounds so 0:20:49.000 --> 0:20:51.960 different from the way we think of computing today, where 0:20:52.000 --> 0:20:55.680 you're using microprocessors and you know, a user interface looking 0:20:55.720 --> 0:20:58.560 at screen. This guy is using test tubes and molecules 0:20:59.160 --> 0:21:02.600 um and he was actually thinking at the time that 0:21:03.480 --> 0:21:05.480 this would be DNA computing is going to be the 0:21:05.560 --> 0:21:08.440 future because it packs so much information in such a 0:21:08.600 --> 0:21:12.840 small form factor and it's plentiful because there's a lot 0:21:12.880 --> 0:21:18.960 of life out there, and organic life relies on DNA heavily. 0:21:19.240 --> 0:21:21.800 There's some that rely on RNA, but we're not going 0:21:21.840 --> 0:21:26.440 to go into that. But Anyway, a great amount of 0:21:26.560 --> 0:21:28.680 organic life out there has lots and lots of DNA, 0:21:28.800 --> 0:21:32.919 so that we've got plenty of materials to work from. Uh. 0:21:33.359 --> 0:21:36.960 What's interesting is that since that time where his first 0:21:37.000 --> 0:21:41.360 experiments were showing the viability of a DNA computer, our 0:21:41.400 --> 0:21:46.920 ability to sequence synthetic DNA has improved to the point 0:21:47.000 --> 0:21:50.760 where organic DNA is not really what we care about anymore. 0:21:51.640 --> 0:21:54.960 We can synthesize DNA in the lab and just make 0:21:55.000 --> 0:21:58.159 it ourselves so we don't have to um harvest it. 0:21:59.720 --> 0:22:02.280 As Chris was saying in the pre show, you know, 0:22:02.720 --> 0:22:05.880 it would be a totally different world if you realize 0:22:05.880 --> 0:22:07.760 that your computer was running out a memory, so you 0:22:07.920 --> 0:22:10.560 chucked another hamster into your machine so that you could 0:22:10.760 --> 0:22:13.040 finish whatever it was you were doing. That was a 0:22:13.080 --> 0:22:16.440 particularly gory idea. Well we didn't, but yeah, I left 0:22:16.480 --> 0:22:19.560 out the part about the grinding noises, you know, and 0:22:19.920 --> 0:22:24.320 for flying out the back you yeah, yeah, And I 0:22:24.400 --> 0:22:30.080 thought that was my contribution. Um yeah. They University of Rochester. 0:22:30.200 --> 0:22:34.760 There were some researchers that found ways to use DNA 0:22:34.920 --> 0:22:40.240 to create logic gates. Again in the n it looks 0:22:40.280 --> 0:22:44.280 like um so uh, and that's we've touched on on 0:22:44.520 --> 0:22:48.760 several occasions, but that those logic gates are basically key 0:22:48.840 --> 0:22:52.960 to classic computing. Yeah, this is what, uh, this is. 0:22:53.160 --> 0:22:56.400 This is what allows the computer to dictate how information 0:22:56.520 --> 0:22:59.760 moves through it so that it has any meaning. You know. 0:22:59.800 --> 0:23:04.720 The logic gates essentially dictate whether the zero or one 0:23:04.880 --> 0:23:07.080 that goes into the gate comes out at zero or 0:23:07.160 --> 0:23:10.160 one on the other side or something. Usually it's a pair. 0:23:11.240 --> 0:23:13.439 If it's a zero and a one on the other 0:23:13.480 --> 0:23:14.440 side of the gate, is that going to be a 0:23:14.480 --> 0:23:16.160 one or zero? And it all depends on the type 0:23:16.200 --> 0:23:19.119 of gate it is. UM And of course you you 0:23:19.240 --> 0:23:22.040 can link a bunch of gates together to create all 0:23:22.160 --> 0:23:25.200 sorts of different outcomes depending upon what the input is. 0:23:25.720 --> 0:23:29.440 This is all very important from classical computing. So getting 0:23:29.480 --> 0:23:31.680 to that step of being able to build logic gates 0:23:31.720 --> 0:23:34.520 out of DNA it was pivotal if you want to 0:23:34.680 --> 0:23:38.600 be able to eventually build a true DNA computer. And 0:23:38.960 --> 0:23:43.000 again this is you know, you compare the components of 0:23:43.440 --> 0:23:48.840 a DNA computer to those of a an inorganic computer. UM, 0:23:48.960 --> 0:23:52.159 and we have, as a Jonathan pointed out, and Gordon 0:23:52.280 --> 0:23:57.040 Moore's uh famous prediction that the transistors would double in 0:23:57.160 --> 0:24:03.400 number per square inch of elicon. Back in the original prediction, UM, 0:24:03.800 --> 0:24:06.880 you know every you know over a certain period of time, 0:24:06.920 --> 0:24:09.359 which again has changed, you know, year, year and a half, 0:24:09.400 --> 0:24:12.920 two years. The thing is, Um, we're talking about a 0:24:13.400 --> 0:24:16.479 flat piece of silicon. And we've also talked about how 0:24:16.600 --> 0:24:20.960 hard drives. The classical hard drive, UM, you know has 0:24:21.320 --> 0:24:23.280 so much information on it. It's in a it's in 0:24:23.359 --> 0:24:28.320 a flat plane. We've talked about electronic memory and how 0:24:28.880 --> 0:24:31.560 you know this information is is getting stored, but we've 0:24:31.600 --> 0:24:35.600 basically been talking two dimensional and and a long time 0:24:35.640 --> 0:24:38.720 ago we talked about processors and how at some point, 0:24:39.000 --> 0:24:42.720 due to the limitations of physics, like it's at some 0:24:42.840 --> 0:24:45.920 point electrons will begin to tunnel through layers of the 0:24:46.000 --> 0:24:50.119 material used to create transistors, basically making them ineffective. So 0:24:50.240 --> 0:24:55.680 at some point, theoretically the traditional transistor chip is going 0:24:55.760 --> 0:24:58.520 to be so full that you cannot fill it anymore 0:24:58.560 --> 0:25:01.720 without having syria. It's electrical problems. So they were talking 0:25:01.720 --> 0:25:05.760 about going into three D processors. Well, d n a 0:25:06.000 --> 0:25:09.200 kind of goes around that problem or is a natural 0:25:09.320 --> 0:25:11.680 if you will solution. Hey, for once, that wasn't a 0:25:11.800 --> 0:25:18.119 pun intended UM, because DNA is volumetric. It isn't It 0:25:18.200 --> 0:25:22.040 can fit because of its its natural characteristics. It doesn't 0:25:22.119 --> 0:25:25.879 have to be in a two dimensional flat shape. You 0:25:25.920 --> 0:25:28.520 don't have to stretch out the helix and stick it 0:25:28.600 --> 0:25:33.680 on a piece of silicon or whatever to make it work. Um, 0:25:33.960 --> 0:25:37.560 and that gives uh, that gives computing so much more 0:25:37.720 --> 0:25:43.040 advantage to move to a DNA based existence, right. Yeah. 0:25:43.080 --> 0:25:46.680 The the challenge is building eloquently. The challenge is building 0:25:46.720 --> 0:25:52.080 the equipment that allows you to sequence and decode that information, 0:25:52.280 --> 0:25:55.879 because you know that's where that's where the bottleneck is 0:25:55.960 --> 0:25:59.320 right now, is that the It's not simple. Yeah, you 0:25:59.400 --> 0:26:01.800