WEBVTT - TechStuff Classic: How DNA Computers Work 0:00:04.240 --> 0:00:07.240 Welcome to tech Stuff, a production of I Heart Radios 0:00:07.320 --> 0:00:14.080 How Stuff Works. Hey there, everybody, and welcome to tech Stuff. 0:00:14.120 --> 0:00:16.759 I'm your host, Jonathan Strickland. I'm an executive producer with 0:00:16.760 --> 0:00:18.800 How Stuff Works and iHeart radio and I love all 0:00:18.840 --> 0:00:22.560 things tech, and it is time for another classic episode 0:00:22.680 --> 0:00:25.079 of tech Stuff. The episode you are about to hear 0:00:25.400 --> 0:00:30.080 originally published way back on October two thousand and twelve. 0:00:30.360 --> 0:00:33.960 It is called how d n A Computers Work and 0:00:34.080 --> 0:00:37.839 Chris and I dive into the weird, wild world of 0:00:37.920 --> 0:00:42.479 computers based on DNA. Hope you guys enjoy. We were 0:00:42.479 --> 0:00:45.400 going to share some twisted logic with you today. Yes, 0:00:45.560 --> 0:00:54.480 we wanted to talk about dioxy ribonucleic acid computers, DONA, 0:00:54.560 --> 0:00:59.840 DONA no nonda, do NAA d n A computers And 0:01:00.160 --> 0:01:04.119 what is a DNA computer? What would it be? Because 0:01:04.200 --> 0:01:07.560 we're really in the very early stages of using DNA 0:01:07.880 --> 0:01:12.560 for the reasons of uh purposes of a computer. But 0:01:12.720 --> 0:01:15.520 what would a DNA computer be? Why would we even 0:01:15.680 --> 0:01:20.440 use DNA? And what the heck is this DNA stuff? Anyway? Well, 0:01:20.480 --> 0:01:22.039 you know, I've got a USB port in the back 0:01:22.080 --> 0:01:26.840 of my head, so yeah, he also woke up one 0:01:26.920 --> 0:01:28.920 day and he was in a giant battery and he 0:01:28.959 --> 0:01:32.520 had to get out. Turns out Chris is the one. 0:01:32.840 --> 0:01:36.520 And I'm definitely not we got this. You know, We've 0:01:36.520 --> 0:01:39.040 got agents Smith showing up every other day at the 0:01:39.160 --> 0:01:42.240 office and we're like, he's not here, today's teleworking and 0:01:42.520 --> 0:01:46.039 us is irritating. But anyways, a glitch in the matrix DNA. 0:01:46.760 --> 0:01:51.680 So DNA is is is important stuff. I mean, this 0:01:51.840 --> 0:01:57.640 is a molecule that contains information that you know, collectively, 0:01:57.760 --> 0:02:02.840 this information makes makes organisms what they are, yes and 0:02:03.400 --> 0:02:08.760 uh and so biologically DNA is used to store information 0:02:09.520 --> 0:02:13.280 and that is really the key there, you know, saying, 0:02:13.600 --> 0:02:17.079 wait a minute, if DNA stores information for organisms, could 0:02:17.160 --> 0:02:21.320 we use DNA to store information for other purposes. But 0:02:21.800 --> 0:02:25.760 to to really explain this, DNA, it's this, it's it's 0:02:25.800 --> 0:02:31.440 that double helix molecule you're pricing, uh, you know, illustrations 0:02:31.520 --> 0:02:33.000 of it. You may have built a model of it. 0:02:33.560 --> 0:02:36.079 If you are in school, you may be studying this 0:02:36.240 --> 0:02:39.119 so much that the terms I'm going to use you're thinking, Wow, 0:02:39.320 --> 0:02:42.679 he's really glossing over this. But it's because this is 0:02:42.800 --> 0:02:44.960 tech stuff, not stuff to blow your mind. So we're 0:02:45.000 --> 0:02:47.440 not going to go too deep into the cellular biology 0:02:47.560 --> 0:02:50.280 aspect of DNA. Yes, And if you're looking for your 0:02:50.320 --> 0:02:52.720 mind being blown, I'm sorry you've come to the wrong place. 0:02:52.840 --> 0:02:56.000 Right now. DNA has a has a lot of instructions 0:02:56.040 --> 0:02:58.560 in it. Yes, As it turns out, it's a very 0:02:58.639 --> 0:03:03.320 tiny molecule with with a very large capacity for for 0:03:03.440 --> 0:03:06.440 carrying information. Yeah, if you were to actually stretch out 0:03:06.600 --> 0:03:10.280 a DNA molecule and lay it lengthwise, it would end 0:03:10.360 --> 0:03:12.920 up taking much more space than it typically does because 0:03:12.960 --> 0:03:18.600 it has this twisted three dimensional uh uh structure. Hence 0:03:18.720 --> 0:03:22.040 my earlier dumb joke. Right, So this twisted structure actually 0:03:22.040 --> 0:03:29.160 allows this this very dense uh storage medium to exist 0:03:29.320 --> 0:03:33.639 in a relatively small volume of space. Yeah, because you've 0:03:33.639 --> 0:03:36.280 twisted it. And you know, it's the whole thing about 0:03:36.920 --> 0:03:40.160 uh conserving surface area and all that great stuff that 0:03:40.240 --> 0:03:42.320 all my biologist friends go on and on and on 0:03:42.440 --> 0:03:46.560 about and then I end up wandering away. Um. But 0:03:47.360 --> 0:03:54.800 DNA has, among many other attributes, there are pairs of 0:03:55.080 --> 0:04:00.160 bases that that pair up in DNA, and this is 0:04:00.280 --> 0:04:03.400 you know, the the structure of those the sequence of 0:04:03.560 --> 0:04:09.360 those determines what information is stored in that strand of DNA. Okay, 0:04:09.400 --> 0:04:14.920 so those four bases you have ad anine, citazine, guanine, 0:04:15.000 --> 0:04:18.480 and thym ing and usually we just call those A, C, 0:04:19.240 --> 0:04:23.920 G and T. And the way that those are sequenced, 0:04:24.040 --> 0:04:26.920 like I said, within a strand of DNA, determines the 0:04:27.080 --> 0:04:31.760 type of information that that DNA holds. Uh and uh, 0:04:32.920 --> 0:04:37.640 it's it's it's that that forms the basis of the 0:04:37.760 --> 0:04:43.040 idea of using a DNA computer because in our of course, 0:04:43.080 --> 0:04:47.960 in our our classic computer model, we've got computers thinking 0:04:48.440 --> 0:04:55.040 quote unquote thinking in binary right, zeros and ones and 0:04:55.279 --> 0:05:00.800 so uh. With using DNA. Uh, the approach now is 0:05:00.920 --> 0:05:06.080 to associate certain of those bases with zeros and the 0:05:06.200 --> 0:05:09.720 others with ones, and the idea being that way you 0:05:09.839 --> 0:05:14.080 could sequence a DNA down the length of a strand 0:05:14.120 --> 0:05:17.640 of DNA with these zeros and ones. You encode a 0:05:17.720 --> 0:05:20.520 strand of DNA that way, and then you would decode it. 0:05:20.600 --> 0:05:24.880 You would read back those those base pairings and that 0:05:24.880 --> 0:05:28.039 would determine whether each pair was a zero or a one, 0:05:28.720 --> 0:05:32.680 and then you would decode that into binary language, and 0:05:33.200 --> 0:05:36.279 thus you would get back to whatever information you originally 0:05:36.360 --> 0:05:42.400 stored onto the DNA. UM. This is it makes it 0:05:42.480 --> 0:05:45.520 sound pretty simple. But this is high tech science stuff 0:05:45.760 --> 0:05:48.520 right now. Now, granted it's high tech science stuff that 0:05:48.760 --> 0:05:54.000 we have made huge advances in over the last two decades. Really, 0:05:55.040 --> 0:06:00.720 So things that were seen as practically a possible two 0:06:00.760 --> 0:06:04.520 decades ago are things that we do almost not quite routinely, 0:06:04.880 --> 0:06:08.560 but with a greater ease than we could have expected. Yeah, 0:06:08.600 --> 0:06:13.680 but over the course of of the last few decades. Um, 0:06:13.760 --> 0:06:16.160 it's the kind of thing that when people see the 0:06:16.240 --> 0:06:19.640 double helix, it's familiar. Um, you know, it's it's it's 0:06:20.400 --> 0:06:24.000 it's high tech science, but it's in our public consciousness too, 0:06:24.279 --> 0:06:27.840 it's in our DNA. There you go the fact that 0:06:27.920 --> 0:06:31.800 that that's a a uh slang term, you know for something. 0:06:31.880 --> 0:06:33.960 When you say it's, it's basically you're saying it's deeply 0:06:34.160 --> 0:06:37.720 ingrained in your personality or whatever you're saying that about. Um, 0:06:38.200 --> 0:06:40.800 you know, it's it's certainly something that that we're all 0:06:40.839 --> 0:06:43.600 familiar with now, but only a few decades ago, you know, 0:06:43.760 --> 0:06:48.479 it was completely foreign to us. Yeah. So yeah, let's 0:06:48.880 --> 0:06:51.280 we'll do a quick, quick rundown of the history of 0:06:51.480 --> 0:06:55.800 our knowledge about DNA, because clearly DNA has existed for 0:06:56.880 --> 0:06:59.400 millions of years, but we've only really been aware of 0:06:59.520 --> 0:07:04.039 it sense about well, we knew something about it back 0:07:04.080 --> 0:07:10.760 in eighteen yes when Freedrich Meischer, who was thank you 0:07:11.000 --> 0:07:15.960 was he was a biologist from Switzerland and he was 0:07:16.120 --> 0:07:21.000 looking at something pretty darn gross. He was looking at 0:07:21.040 --> 0:07:25.480 bandages that had puss on them, and he isolated DNA 0:07:25.760 --> 0:07:28.800 from the pus on the bandages, and he thought that 0:07:29.040 --> 0:07:35.880 perhaps the this stuff, these nucleic acids, which is DNA 0:07:36.200 --> 0:07:40.520 is a nucleic acid. He thought that perhaps this stuff 0:07:40.680 --> 0:07:46.880 might contain information in it that would determine why stuff 0:07:47.160 --> 0:07:49.880 is the way it is so, genetic information. He thought 0:07:49.960 --> 0:07:53.640 that that probably did contain that information, but there was 0:07:53.680 --> 0:07:56.600 no way for him to be able to confirm it. 0:07:57.120 --> 0:08:01.000 He could not point to anything and say see, I'm right. 0:08:01.680 --> 0:08:05.320 So that had to wait for future scientists to uh, 0:08:05.560 --> 0:08:08.560 to really dive into it. Not not the past that 0:08:08.640 --> 0:08:11.560 bi gross, but to really dive into the information and 0:08:11.680 --> 0:08:14.640 study it and and figure out more details. So in 0:08:14.760 --> 0:08:22.360 ninete some scientists at Rockefeller University, including Oswald Avery, showed 0:08:22.440 --> 0:08:27.280 that DNA taken from a bacterium could make a non 0:08:27.600 --> 0:08:34.440 infectious type of bacteria become infectious bacteria. So The thought 0:08:34.600 --> 0:08:38.559 was that there must be some information from this nucleic 0:08:38.640 --> 0:08:43.000 acid taken from one type of bacteria that could transfer 0:08:43.280 --> 0:08:47.000 properties to a different bacteria that otherwise would not have 0:08:47.320 --> 0:08:52.280 that infectious property. But what does it r Yes, that's 0:08:52.360 --> 0:08:55.920 kind of what everyone was saying. Well, there's some sort 0:08:56.040 --> 0:09:00.120 of information holding material here. We don't really in ud 0:09:00.240 --> 0:09:03.880 stand the mechanism by which it stores information, nor how 0:09:04.040 --> 0:09:08.120 does it impart that information uh or or replicated. We 0:09:08.200 --> 0:09:11.520 didn't know that at the time. Uh. And then in 0:09:11.760 --> 0:09:16.679 nineteen fifty two, Alfred Hershey and Martha Chase showed that 0:09:17.280 --> 0:09:22.800 to make new viruses bacteria fage virus injected DNA into 0:09:23.000 --> 0:09:26.599 the host cell, which was important because previously it was 0:09:26.640 --> 0:09:30.600 thought that perhaps it was through protein exchange, but instead 0:09:30.600 --> 0:09:35.480 of protein exchange, it was DNA exchange. So that showed, yes, 0:09:35.640 --> 0:09:38.360 there's something in this. This d N A is what 0:09:38.720 --> 0:09:43.920 is important. And then came along Watson and Crick. Yes, 0:09:44.480 --> 0:09:47.880 James D. Watson and Francis Crick. Yeah. They it was 0:09:48.240 --> 0:09:53.280 clear that, uh, that people were already onto something. Hershey 0:09:53.320 --> 0:09:55.760 and Chase had something there, and it was only a 0:09:55.840 --> 0:09:59.679 year later when Watson and Crick, uh you know, made 0:09:59.679 --> 0:10:04.640 their announcement they had discovered the structure of DNA, right, 0:10:04.720 --> 0:10:08.280 and so this is when we started to really learn 0:10:08.640 --> 0:10:13.199 what how DNA you know, forms, and what shape it 0:10:13.360 --> 0:10:19.160 takes and why that's important. And um So once all 0:10:19.240 --> 0:10:22.000 of that was taken, once we learned all that, we 0:10:22.160 --> 0:10:24.600 began to see that these base pairings I was talking about, 0:10:25.000 --> 0:10:27.760 we learned that they pair in very specific ways. You know, 0:10:27.920 --> 0:10:30.920 I mentioned there are the four different bases. There's A, 0:10:31.559 --> 0:10:35.760 the A, C, G T. Well, half of those A 0:10:36.160 --> 0:10:41.520 and G are called purines. Uh, C and T are 0:10:42.200 --> 0:10:47.839 uh perimidines. I'm glad you took that part. Yeah, me too, 0:10:48.320 --> 0:10:50.280 Uh you know, way back when I was actually really 0:10:50.320 --> 0:10:52.839 good at biology. But man, that was a few decades ago. 0:10:53.000 --> 0:10:58.959 So anyway, uh puriings and peri perim pyrimidines. Look, I 0:10:59.000 --> 0:11:02.200 can't even do it now, periods of paramidines. Still, glad 0:11:02.240 --> 0:11:06.800 you took that bond together. Right, So, uh, you don't 0:11:06.880 --> 0:11:09.439 get two puringes bonding together, and you don't get two 0:11:09.480 --> 0:11:14.640 pyramidines bonding together. And to be even more specific, A 0:11:14.880 --> 0:11:18.640 and T will bond together and C and G will 0:11:18.720 --> 0:11:22.240 bond together. All right, so that that means that you know, 0:11:22.360 --> 0:11:25.199 you can't. You're not going to get a strand of 0:11:25.280 --> 0:11:29.600 DNA where A and C or A and G are 0:11:29.920 --> 0:11:33.599 paired together. It does not happen, right they Structurally that 0:11:33.720 --> 0:11:40.720 doesn't happen. So uh. That also dictates the rationale behind 0:11:41.000 --> 0:11:45.280 using uh these pairings as zeros and ones, because you 0:11:45.600 --> 0:11:48.679 can either have uh. You can either have the A 0:11:48.840 --> 0:11:52.079 T pairing or the C G pairing, right, so that 0:11:52.320 --> 0:11:55.200 that lets you say, okay, well that's binary. It's either 0:11:55.240 --> 0:11:59.000 you you just designate that one means one, pairing means zero, 0:11:59.160 --> 0:12:02.720 the other pairing means one. Um. If it weren't that case, 0:12:03.040 --> 0:12:08.760 if we could have multiple pairing multiple uh uh, like 0:12:09.040 --> 0:12:11.360 like if A could pair with G instead of just 0:12:11.480 --> 0:12:14.080 A and T, then you would say, all right, well, 0:12:14.120 --> 0:12:17.520 now we've got a system that goes beyond binary, which, 0:12:17.800 --> 0:12:22.880 in theory, if you completely change the way computers work, 0:12:23.840 --> 0:12:29.840 would mean that you could dramatically increase parallel processing because 0:12:29.920 --> 0:12:32.559 you could designate things. It would almost be like the 0:12:32.720 --> 0:12:37.640 cubits of a quantum computer, where you know the basic 0:12:37.679 --> 0:12:41.160 explanation as a cubit represents both a zero and a 0:12:41.240 --> 0:12:45.160 one and all values in between in superposition of one another, 0:12:46.160 --> 0:12:50.240 and that if you have enough cubits, you can perform 0:12:50.400 --> 0:12:56.200 a massive parallel processing problem all at the same time 0:12:56.320 --> 0:13:00.800 because those that that one group of cubits is behaving 0:13:00.840 --> 0:13:04.640 as if it's uh, you know, a huge number of 0:13:05.720 --> 0:13:09.480 traditional bits. I think it's important to remember too that 0:13:09.559 --> 0:13:14.160 no matter how many bases DNA has, they all belong 0:13:14.240 --> 0:13:16.480 to us. Oh I knew it. I knew it. I 0:13:16.640 --> 0:13:18.760 was like, oh, I's gonna do an all your base 0:13:18.840 --> 0:13:21.120 I belonged to us if someone set us up the bomb, 0:13:22.040 --> 0:13:24.880 so well, it could be Actually, if you if you 0:13:25.480 --> 0:13:28.959 were trying to if those pairs become corrupted, they will 0:13:29.000 --> 0:13:33.000 not work and uh and a cell can die. Actually, 0:13:33.000 --> 0:13:35.080 we're getting a lot of this information to from our 0:13:35.160 --> 0:13:37.640 our excellent article on how stuff Works dot com about 0:13:37.720 --> 0:13:41.199 how DNA works. It gets into a whole lot more detailed, right, Yeah, 0:13:41.200 --> 0:13:43.200 if you want to learn more about and and it's 0:13:43.320 --> 0:13:45.600 very accessible. It's a very accessible article. So if you're 0:13:45.640 --> 0:13:47.760 curious about you know, you've always heard about d N A, 0:13:47.880 --> 0:13:50.160 and you've heard about DNA testing, and you know about 0:13:50.280 --> 0:13:55.160 chromosomes and genes, but you're not really you know, beyond that, 0:13:55.360 --> 0:13:57.720 you're kind of confused. I highly recommend you read how 0:13:57.840 --> 0:14:00.640 DNA works at how stuff works dot com. We also 0:14:00.679 --> 0:14:03.199 have an article on how DNA computers work, which is 0:14:03.200 --> 0:14:07.760 pretty interesting because it's talking about an earlier era of 0:14:07.920 --> 0:14:12.080 DNA computers, but recent developments have really brought it brought 0:14:12.120 --> 0:14:17.559 to lights some interesting, uh, new technologies and new use 0:14:17.679 --> 0:14:20.640 cases for d n A and we'll get into those 0:14:20.640 --> 0:14:22.720 in a second. Yeah, It's it's funny that you say that, 0:14:22.840 --> 0:14:25.680 because I'm sure that people this is futuristic enough where 0:14:25.720 --> 0:14:28.640 people are saying, what are you talking about new developments? 0:14:28.680 --> 0:14:30.880 We haven't heard of a d n A computer before? 0:14:31.000 --> 0:14:33.520 But yeah, that's that's not really surprising. This is the 0:14:33.600 --> 0:14:36.440 kind of thing like like quantum computing, where they've been 0:14:36.480 --> 0:14:38.400 working on it for some time, but it's not at 0:14:38.440 --> 0:14:41.240 a point where they can really, you know, put something 0:14:41.320 --> 0:14:43.120 on a shelf and go look at this. Yeah, yeah, 0:14:43.760 --> 0:14:46.080 where people really take notice of it. In general, this 0:14:46.240 --> 0:14:49.800 is all stuff that's taking place in universities and research facilities, 0:14:49.960 --> 0:14:52.800 and it's you know, most of these machines that are 0:14:52.840 --> 0:14:56.280 being made now or or these implementations of using DNA 0:14:56.440 --> 0:15:01.440 for information digital information are are really in the prototype stage. 0:15:01.720 --> 0:15:05.480 But we're getting the technology that allows us to create 0:15:05.600 --> 0:15:09.680 these machines is becoming more and more sophisticated and less expensive, 0:15:10.080 --> 0:15:14.320 which of course is key huge any news. And Gordon 0:15:14.400 --> 0:15:18.040 Moore explained that back and when he did his his 0:15:18.160 --> 0:15:21.560 paper about cramming more components onto an integrated circuit. His 0:15:21.720 --> 0:15:24.160 point was not just that technology was advancing to a 0:15:24.160 --> 0:15:27.240 point where we could shrink stuff down and fit twice 0:15:27.280 --> 0:15:30.640 as many components onto a square inch of silicon as 0:15:30.640 --> 0:15:32.720 we could a year ago. It was also that the 0:15:32.760 --> 0:15:36.240 manufacturing process was becoming efficient enough and cheap enough where 0:15:36.320 --> 0:15:40.920 that made sense. So same sort of thing here. Well, 0:15:41.880 --> 0:15:45.280 all right, so we've we've determined that DNA contains information. 0:15:45.560 --> 0:15:48.400 It because of its very structure, it can contain a 0:15:48.560 --> 0:15:51.720 lot of information in a small volume. Uh. And then 0:15:51.840 --> 0:15:55.480 it wasn't until about nine and I remember it was 0:15:55.560 --> 0:15:57.680 the it was the fifties, the early fifties when we 0:15:57.720 --> 0:16:00.440 started to really understand what DNA was and how how 0:16:00.760 --> 0:16:03.880 it formed and how and its structured and everything like that. 0:16:04.600 --> 0:16:09.440 Into a man named Leonard Edelman came up with this idea. 0:16:09.520 --> 0:16:12.880 He sort of uh introduced the idea of using DNA 0:16:13.760 --> 0:16:18.840 to solve math problems. And it was essentially this idea 0:16:18.920 --> 0:16:24.120 of coding DNA as if it were a strip of 0:16:24.320 --> 0:16:30.080 binary code. And so he took this idea and he 0:16:30.320 --> 0:16:33.160 sort of ran with it. He began to formulate an 0:16:33.200 --> 0:16:35.760 idea about how to how to create an experiment that 0:16:35.880 --> 0:16:39.520 could show that this would work. And it's funny because 0:16:40.200 --> 0:16:42.680 it's talking about a DNA computer, but if you read 0:16:42.720 --> 0:16:45.600 about the experiment, it sounds more like someone in a 0:16:45.720 --> 0:16:51.920 chemistry lab mixing various chemical compositions together and then coming 0:16:52.000 --> 0:16:54.920 up with a solution at the end of it. And 0:16:55.400 --> 0:16:58.560 that's it turns out that this is a computational solution, 0:16:58.760 --> 0:17:02.960 not just a chemical solution. I see what you did there, 0:17:03.080 --> 0:17:05.119 Ye little word play there. Yeah, it's a little a 0:17:05.119 --> 0:17:10.879 little incredible. So he yeah, he um, he dissolved my objections. 0:17:11.840 --> 0:17:13.879 Chris and I have more to say about DNA in 0:17:13.960 --> 0:17:16.680 just a moment, but first let's take a quick break 0:17:16.960 --> 0:17:27.240 to thank our sponsor. Let me read I'll read the 0:17:27.400 --> 0:17:30.560 steps from our article on DNA computers, because I want 0:17:30.640 --> 0:17:33.800 to explain how this early, early, early implementation of a 0:17:33.880 --> 0:17:37.320 DNA computer, how it how it played out, and it's 0:17:37.440 --> 0:17:42.160 kind of amazing. All right. Here are the steps. Number 0:17:42.200 --> 0:17:45.840 one strands of DNA represent the seven cities now when 0:17:45.920 --> 0:17:47.680 it says seven cities in here, what he was doing 0:17:47.760 --> 0:17:49.880 was he was trying to solve something called the traveling 0:17:50.000 --> 0:17:54.760 salesman problem, also the directed Hamilton's path problem. The idea 0:17:54.840 --> 0:17:57.760 being that you're supposed to find the shortest route between 0:17:58.520 --> 0:18:01.360 a group of cities and and it could be any 0:18:01.440 --> 0:18:03.760 number really of cities, but you have to only go 0:18:04.000 --> 0:18:08.160 through each city one time, um, and it becomes more complex. 0:18:08.440 --> 0:18:10.600 This is this is why this is such a fascinating 0:18:10.640 --> 0:18:13.440 problem uh as Jonathan pointed out to me right before, 0:18:13.600 --> 0:18:16.480 he reminded me that this is something that quantum computing 0:18:16.680 --> 0:18:20.080 is fascinated with because this is such a I don't 0:18:20.119 --> 0:18:22.680 know what you call it, thorny, a thorny problem. So 0:18:22.800 --> 0:18:25.200 it was that problem that they were were that he 0:18:25.280 --> 0:18:28.639 wanted to work on, and he chose, I believe seven cities, 0:18:28.760 --> 0:18:31.000 he said, that is his benchmark he wanted to do. 0:18:31.160 --> 0:18:33.159 And see, this is this is an interesting problem for 0:18:33.600 --> 0:18:37.399 uh in computers because think about it, you've got seven cities, 0:18:37.480 --> 0:18:39.200 you can only travel through each city once. You have 0:18:39.320 --> 0:18:42.480 to find the most efficient pathway to go. Well, the 0:18:42.520 --> 0:18:45.639 way a computer would do this, generally speaking, is to 0:18:45.840 --> 0:18:52.359 start going through every single possible um permutation of that 0:18:52.560 --> 0:18:56.280 trip going from city to city and determining which of 0:18:56.320 --> 0:18:57.879 those is the most efficient by the end of it, 0:18:57.960 --> 0:19:02.000 by comparing them all, which can take ages and as 0:19:02.200 --> 0:19:04.560 as of course, as you add more cities, as you 0:19:04.600 --> 0:19:09.440 add complexity to the problem, it creates an exponentially more 0:19:09.600 --> 0:19:12.080 difficult problem for the computer to solve. You know, I 0:19:12.119 --> 0:19:15.800 don't think it's that unlike trying to crack a password. Yeah, 0:19:16.160 --> 0:19:18.560 in the in the you know, other references we've made 0:19:18.560 --> 0:19:21.520 to these again, parallel processing. That's another reason why quantum 0:19:21.520 --> 0:19:25.520 computers are very scary for anyone who's in cryptography who 0:19:25.600 --> 0:19:28.360 wants to create good encryption, because they're talking about using 0:19:28.359 --> 0:19:31.680 parallel processing to attack, you know, do a brute force 0:19:31.720 --> 0:19:36.760 attack on a password. You can really reduce the amount 0:19:36.760 --> 0:19:39.440 of time it would take you to crack a password, 0:19:39.480 --> 0:19:42.200 like a password that would probably take you thousands of 0:19:42.359 --> 0:19:46.200 years in classic computer time might only take an hour 0:19:46.680 --> 0:19:49.719 in using a quantum computer because it's using that parallel approach. 0:19:50.000 --> 0:19:53.119 So just remember, quantum computing is the cure for the 0:19:53.200 --> 0:19:57.960 common code. Man, what is it with you today? I 0:19:58.040 --> 0:20:01.720 don't know. Chris is in a move anyway? All right, 0:20:02.240 --> 0:20:05.720 Getting back to getting back to this thing, this set 0:20:05.760 --> 0:20:09.280 of steps. All right, So Edelman creates strands of DNA 0:20:09.400 --> 0:20:15.159 that represent the seven cities. Uh and so it's these A, T, 0:20:15.440 --> 0:20:21.160 and CG pairings and then um, these various sequences represent 0:20:21.280 --> 0:20:25.000 each city and possible flight path. He then took the 0:20:25.160 --> 0:20:29.280 molecules that these strands of DNA and mixed them in 0:20:29.359 --> 0:20:32.040 a test tube, and some of the strands of DNA 0:20:32.200 --> 0:20:34.840 stuck together in a chain. Of those strands represented a 0:20:34.960 --> 0:20:39.840 potential answer to that question, which of these you know, 0:20:39.920 --> 0:20:43.320 which route is the most efficient. Within a few seconds, 0:20:43.480 --> 0:20:47.000 all of the possible combinations of DNA strands were created 0:20:47.080 --> 0:20:49.840 in the test tube, and then Adelman eliminated the wrong 0:20:49.920 --> 0:20:53.240 molecules through chemical reactions, which left behind only the flight 0:20:53.320 --> 0:20:58.240 paths that connect all seven cities. So here he was 0:20:58.440 --> 0:21:03.760 doing chemistry and looking at molecules by uh and it 0:21:03.920 --> 0:21:07.640 was and it was biological chemistry because he was using 0:21:07.800 --> 0:21:13.159 organic DNA um and and trying to come up with 0:21:13.200 --> 0:21:14.920 the answer that way, which is pretty interesting to me. 0:21:15.000 --> 0:21:18.200 I mean, it looks that sounds so different from the 0:21:18.240 --> 0:21:21.520 way we think of computing today, where you're using microprocessors 0:21:21.600 --> 0:21:24.320 and you know, the user interface looking at screen this 0:21:24.400 --> 0:21:28.639 guy is using test tubes and molecules um and he 0:21:28.840 --> 0:21:31.920 was actually thinking at the time that this would be 0:21:32.119 --> 0:21:34.680 DNA computing is going to be the future because it 0:21:34.800 --> 0:21:37.399 packs so much information in such a small form factor 0:21:37.720 --> 0:21:41.120 and it's plentiful. Yes, because there's a lot of life 0:21:41.160 --> 0:21:47.320 out there, and organic life relies on DNA heavily. There's 0:21:47.359 --> 0:21:49.760 some that rely on RNA, but we're not going to 0:21:49.800 --> 0:21:54.760 go into that. But anyway, a great amount of organic 0:21:54.840 --> 0:21:56.720 life out there has lots and lots of DNA, so 0:21:56.880 --> 0:22:00.800 the we've got plenty of materials to work from. Uh. 0:22:01.240 --> 0:22:04.800 What's interesting is that since that time where his first 0:22:04.880 --> 0:22:09.200 experiments were showing the viability of a DNA computer, our 0:22:09.280 --> 0:22:14.800 ability to sequence synthetic DNA has improved to the point 0:22:14.880 --> 0:22:18.600 where organic DNA is not really what we care about anymore. 0:22:19.520 --> 0:22:22.800 We can synthesize DNA in the lab and just make 0:22:22.840 --> 0:22:26.040 it ourselves so we don't have to um harvest it. 0:22:27.600 --> 0:22:30.159 As Chris was saying in the pre show, you know, 0:22:30.600 --> 0:22:33.760 it would be a totally different world if you realize 0:22:33.760 --> 0:22:35.639 that your computer was running out a memory, so you 0:22:35.800 --> 0:22:38.400 checked another hamster into your machine so that you could 0:22:38.640 --> 0:22:40.879 finish whatever it was you were doing. That was a 0:22:40.920 --> 0:22:44.000 particularly gory idea. Well we didn't know, but yeah, I 0:22:44.119 --> 0:22:46.760 left out the part about the grinding noises, you know, 0:22:47.400 --> 0:22:52.200 and for flying out the back you yeah, and I 0:22:52.280 --> 0:22:57.960 thought that was my contribution. Um, yeah, they University of Rochester, 0:22:58.080 --> 0:23:02.600 there were some researchers at found ways to use DNA 0:23:02.800 --> 0:23:08.200 to create logic gates. Again in the it looks like 0:23:08.840 --> 0:23:13.240 um so uh and that's we've touched on on several occasions, 0:23:13.280 --> 0:23:18.680 but that those logic gates are basically key to classic computing. Yeah, 0:23:18.760 --> 0:23:22.080 this is what uh, this is. This is what allows 0:23:22.119 --> 0:23:25.200 the computer to dictate how information moves through it so 0:23:25.320 --> 0:23:28.480 that it has any meaning. You know. The logic gates 0:23:28.960 --> 0:23:33.360 essentially dictate whether the zero or one that goes into 0:23:33.400 --> 0:23:35.359 the gate comes out at zero or one on the 0:23:35.400 --> 0:23:39.400 other side or something. Usually it's a pair. If it's 0:23:39.400 --> 0:23:41.600 a zero and a one on the other side of 0:23:41.600 --> 0:23:42.960 the gate, is that going to be a one or zero? 0:23:43.040 --> 0:23:45.600 And it all depends on the type of gate it is. Um. 0:23:45.840 --> 0:23:48.320 And of course you you can link a bunch of 0:23:48.359 --> 0:23:51.800 gates together to create all sorts of different outcomes depending 0:23:51.880 --> 0:23:54.880 upon what the input is. This is all very important 0:23:55.080 --> 0:23:58.280 from classical computing. So getting to that step of being 0:23:58.320 --> 0:24:00.200 able to build logic gates out of d in a 0:24:00.600 --> 0:24:02.960 it was pivotal if you want to be able to 0:24:03.040 --> 0:24:07.600 eventually build a true DNA computer. And again this is 0:24:08.359 --> 0:24:12.280 you know, you compare the components of a DNA computer 0:24:12.440 --> 0:24:17.200 to those of a an inorganic computer. UM. And we have, 0:24:17.720 --> 0:24:21.879 as a Jonathan pointed out and Gordon Moore's uh famous 0:24:21.920 --> 0:24:27.240 prediction that the transistors would double in number per square 0:24:27.280 --> 0:24:31.720 inch of silicon back in the original prediction, UM, you 0:24:31.800 --> 0:24:34.760 know every you know over a certain period of time, 0:24:34.800 --> 0:24:37.200 which again has changed, you know, year, year and a half, 0:24:37.280 --> 0:24:40.760 two years. The thing is, um, we're talking about a 0:24:41.240 --> 0:24:44.359 flat piece of silicon. And we've also talked about how 0:24:44.440 --> 0:24:48.840 hard drives, the classical hard drive, UM, you know has 0:24:49.160 --> 0:24:51.159 so much information on it. It's in a it's in 0:24:51.200 --> 0:24:56.200 a flat plane. We've talked about electronic memory and how 0:24:56.760 --> 0:24:59.119 you know this information is is getting stored. But we 0:24:59.480 --> 0:25:03.480 basically been talking two dimensional and and a long time 0:25:03.520 --> 0:25:06.600 ago we talked about processors and how at some point, 0:25:06.840 --> 0:25:10.600 due to the limitations of physics like it's at some 0:25:10.720 --> 0:25:13.800 point electrons will begin to tunnel through layers of the 0:25:13.880 --> 0:25:18.000 material used to create transistors, basically making them ineffective. So 0:25:18.080 --> 0:25:23.560 at some point, theoretically the traditional transistor chip is going 0:25:23.640 --> 0:25:26.359 to be so full that you cannot fill it anymore 0:25:26.440 --> 0:25:29.840 without having serious electrical problems. So they were talking about 0:25:29.880 --> 0:25:34.040 going into three D processors. Well, d N a kind 0:25:34.080 --> 0:25:37.320 of goes around that problem or is a natural if 0:25:37.359 --> 0:25:39.840 you will solution. Hey, for once, that wasn't a pun 0:25:40.080 --> 0:25:46.240 intended um, because DNA is volumetric. It isn't it can 0:25:46.480 --> 0:25:50.040 fit because of its its natural characteristics. It doesn't have 0:25:50.200 --> 0:25:53.960 to be in a two dimensional flat shape. You don't 0:25:54.000 --> 0:25:56.520 have to stretch out the helix and stick it on 0:25:56.600 --> 0:26:01.560 a piece of silicon or whatever to make it work. Um, 0:26:01.840 --> 0:26:05.400