1 00:00:05,166 --> 00:00:06,240 Alright! 2 00:00:06,240 --> 00:00:09,961 This is a sciene talk, so please block the exits, 3 00:00:09,961 --> 00:00:14,390 keep people from escaping and we'll see where we'll end up. 4 00:00:14,390 --> 00:00:17,849 My talk is about evolution and lots of things have been said about evolution, 5 00:00:17,849 --> 00:00:19,581 lots of things have been done. 6 00:00:19,581 --> 00:00:21,477 I want to make one disclaimer: 7 00:00:21,477 --> 00:00:26,426 I've only been given two and a half hours to talk about this by the organisers, 8 00:00:26,426 --> 00:00:31,868 so I have to give a short introduction to some aspects -- to a summary of evolution. 9 00:00:31,868 --> 00:00:34,001 I'm going to skip over things, going to simplify things, 10 00:00:34,001 --> 00:00:35,181 and you're going to have to live with it. 11 00:00:35,181 --> 00:00:39,775 But the points I'm making will hopefully make some sense. 12 00:00:39,775 --> 00:00:43,068 Evolution: everybody knows the theory 13 00:00:43,068 --> 00:00:45,505 or thinks that they know it. 14 00:00:45,505 --> 00:00:47,406 It's a work in progress; that's very important. 15 00:00:47,406 --> 00:00:48,767 There's many things we understand. 16 00:00:48,767 --> 00:00:51,228 There's many facts that tell us evolution is right. 17 00:00:51,228 --> 00:00:53,827 There's not a single scientist 18 00:00:53,827 --> 00:00:57,442 that really works by scientific methods, 19 00:00:57,442 --> 00:01:02,284 that looks at facts and uses theories that doubts the theory of evolution. 20 00:01:02,284 --> 00:01:06,546 That does not mean that the theory of evolution is there, that it's not changing. 21 00:01:06,546 --> 00:01:09,714 We always discover more and we need to adapt our theory. 22 00:01:09,714 --> 00:01:11,509 It's very important. Some people think 23 00:01:11,509 --> 00:01:13,704 that because we sometimes discover something 24 00:01:13,704 --> 00:01:15,849 and we need to make slight changes to our theory 25 00:01:15,849 --> 00:01:17,777 that the theory is not valid. 26 00:01:17,777 --> 00:01:20,847 And instead they come up with a theory for which there is no proof at all 27 00:01:20,847 --> 00:01:23,403 and they think that's a much better option. 28 00:01:23,403 --> 00:01:24,884 I don't think so. 29 00:01:24,884 --> 00:01:27,706 Alright! Let's start with this guy. 30 00:01:27,706 --> 00:01:32,059 As you can tell, very fashionable: French. 31 00:01:32,059 --> 00:01:33,582 Jean-Baptiste Lamarck. 32 00:01:33,582 --> 00:01:36,802 He was one of the first people to come up with a coherent theory of evolution. 33 00:01:36,802 --> 00:01:41,033 He's done many more things, but his theory is quite extraordinary. 34 00:01:41,033 --> 00:01:44,047 And one of the aspects of his theory is that 35 00:01:44,047 --> 00:01:48,917 he believed in the inheritence of acquired characteristics. 36 00:01:48,917 --> 00:01:50,298 What does he mean by that is 37 00:01:50,298 --> 00:01:52,232 that, well, look at these giraffes. 38 00:01:52,232 --> 00:01:56,041 It's a very easy way to explain this idea by Lamarck. 39 00:01:56,041 --> 00:01:59,264 Everybody knows that a giraffe has got a remarkably long neck. 40 00:01:59,264 --> 00:02:02,344 How does it get the long neck? Well -- 41 00:02:02,344 --> 00:02:05,578 it's trying to eat leaves on the tree. 42 00:02:05,578 --> 00:02:07,737 And it stretches it's neck. 43 00:02:07,737 --> 00:02:12,857 And therefore the little kiddy giraffes will have slightly longer necks. 44 00:02:12,857 --> 00:02:16,094 And again this repeats, and that's how the giraffe got a long neck. 45 00:02:16,094 --> 00:02:18,999 Seems a bit silly to us but it's actually a great idea. 46 00:02:18,999 --> 00:02:21,129 He was going with the data he had. 47 00:02:21,129 --> 00:02:26,377 Wonderful theory, except it's not right. 48 00:02:26,377 --> 00:02:28,097 In came Darwin. 49 00:02:28,097 --> 00:02:30,806 And enough has been said and done about Darwin 50 00:02:30,806 --> 00:02:32,501 over the last year especially. 51 00:02:32,501 --> 00:02:33,838 He's been great. 52 00:02:33,838 --> 00:02:36,665 One of the things that he did is 53 00:02:36,665 --> 00:02:38,873 he introduced two key concepts 54 00:02:38,873 --> 00:02:42,645 namely variation and selection. 55 00:02:42,645 --> 00:02:44,338 And with variation he just said: 56 00:02:44,338 --> 00:02:47,537 Well, these giraffes don't stretch their neck 57 00:02:47,537 --> 00:02:50,473 -- well maybe they do, but they are born with short and longer necks. 58 00:02:50,473 --> 00:02:54,711 There's just this natural variation amongst giraffes. 59 00:02:54,711 --> 00:02:58,856 And the lucky ones that have the long necks, can reach more leaves. 60 00:02:58,856 --> 00:03:02,139 And as you know, you only think about sex after you're not hungry anymore, 61 00:03:02,139 --> 00:03:05,359 so -- (Laughter) 62 00:03:05,359 --> 00:03:07,629 they're going to reproduce because they're not hungry anymore. 63 00:03:07,629 --> 00:03:11,909 They're going to get little giraffes with slightly longer necks 64 00:03:11,909 --> 00:03:13,701 and that's how evolution happens. 65 00:03:13,701 --> 00:03:16,295 So, this is the selection part 66 00:03:16,295 --> 00:03:17,801 and then there's natural variation. 67 00:03:17,801 --> 00:03:20,097 He didn't really say how the natural variation occured, 68 00:03:20,097 --> 00:03:22,404 he didn't really have answers to that. 69 00:03:22,404 --> 00:03:24,472 He thought about it a lot. 70 00:03:24,472 --> 00:03:26,590 But he really separated the two processes. 71 00:03:26,590 --> 00:03:28,361 This is also what made him so controversial, 72 00:03:28,361 --> 00:03:30,157 because it was very cruel, 73 00:03:30,157 --> 00:03:32,638 it's a very cruel way of having evolution. 74 00:03:32,638 --> 00:03:34,243 There's giraffes dying. 75 00:03:34,243 --> 00:03:38,437 There's poor giraffes with short necks dying here. 76 00:03:38,437 --> 00:03:39,365 Alright! 77 00:03:39,365 --> 00:03:41,965 And this fellow here looks very stern. 78 00:03:41,965 --> 00:03:44,483 He's German. (Laughter) 79 00:03:44,483 --> 00:03:47,546 August Weissmann, great great biologist. 80 00:03:47,546 --> 00:03:51,009 He really -- one of the things he did 81 00:03:51,009 --> 00:03:53,907 is really try to proof that variation and selection 82 00:03:53,907 --> 00:03:56,043 are completely independent. 83 00:03:56,043 --> 00:03:57,316 And one way he did this 84 00:03:57,316 --> 00:04:00,178 -- so he really sort of tried to kill the old idea by Lamarck 85 00:04:00,178 --> 00:04:05,400 that the length of the neck of the giraffe has really nothing to do 86 00:04:05,400 --> 00:04:07,603 with what it did in its lifetime 87 00:04:07,603 --> 00:04:10,555 and its stretching out for trees. 88 00:04:10,555 --> 00:04:11,643 So one of the things he did 89 00:04:11,643 --> 00:04:13,365 -- he's really very famous for this experiment, 90 00:04:13,365 --> 00:04:15,639 although it's not his best experiment -- 91 00:04:15,639 --> 00:04:17,447 he took mice as soon as they were born, 92 00:04:17,447 --> 00:04:20,822 cut off the tail then bred more mice 93 00:04:20,822 --> 00:04:22,313 as soon as the little mice were born 94 00:04:22,313 --> 00:04:24,748 cut off the tail again and just repeated this. 95 00:04:24,748 --> 00:04:26,347 And in the end what he noticed was 96 00:04:26,347 --> 00:04:28,660 that all these new mice, these little mice, 97 00:04:28,660 --> 00:04:31,106 even after he's done this for 30 generations 98 00:04:31,106 --> 00:04:35,592 still had tails that were just as long as the original mice. 99 00:04:35,592 --> 00:04:39,290 So it's a great way of disproving Lamarck. 100 00:04:39,290 --> 00:04:42,258 I would say, he should have relaxed, sit back, 101 00:04:42,258 --> 00:04:45,021 thought about looking at the Jewish male population 102 00:04:45,021 --> 00:04:50,965 and we wouldn't even had to do his experiment. (Laughter) 103 00:04:50,965 --> 00:04:57,004 So, he came up with a, I think, much more important finding, though. 104 00:04:57,004 --> 00:04:59,803 And really amazing work that he did. 105 00:04:59,803 --> 00:05:02,723 Where he actually said that, 106 00:05:02,723 --> 00:05:06,515 even early in our lives, and I'm talking about embryo's, 107 00:05:06,515 --> 00:05:08,144 what he called our germ cells, 108 00:05:08,144 --> 00:05:11,082 these are the cells that are used to reproduce, 109 00:05:11,082 --> 00:05:13,293 are separated from the rest of the embryo. 110 00:05:13,293 --> 00:05:15,964 You can see them here as little dots. 111 00:05:15,964 --> 00:05:19,494 And they separate and we all know where they end up in the end. 112 00:05:19,494 --> 00:05:21,352 And the strong point in that -- 113 00:05:21,352 --> 00:05:23,001 he was totally right about this -- 114 00:05:23,001 --> 00:05:25,133 and the strong point about this is that -- 115 00:05:25,133 --> 00:05:26,420 pretty much what he was saying is -- 116 00:05:26,420 --> 00:05:31,003 when the giraffe stretches its neck, it's not stretching its testicles. 117 00:05:31,003 --> 00:05:34,588 So how can this have any effect on your germ cells. 118 00:05:34,588 --> 00:05:36,374 It's a very strong point, then again, 119 00:05:36,374 --> 00:05:38,027 at least for complex organisms, 120 00:05:38,027 --> 00:05:41,093 he set apart variation and selection. 121 00:05:41,093 --> 00:05:43,302 The forces that will select you 122 00:05:43,302 --> 00:05:46,728 are independent of this variation that you have. 123 00:05:46,728 --> 00:05:47,930 Again a bit later 124 00:05:47,930 --> 00:05:52,397 these two fine gentlemen here, Luria and Delbrück, 125 00:05:52,397 --> 00:05:54,753 were working in Cold Spring Harbor in the U.S. 126 00:05:54,753 --> 00:05:59,960 where they were doing multiple amazing experiments 127 00:05:59,960 --> 00:06:02,435 and one of them got them the Nobel Prize. 128 00:06:02,435 --> 00:06:05,079 And they were working on this virus here, 129 00:06:05,079 --> 00:06:06,720 which looks a bit like a Moon lander 130 00:06:06,720 --> 00:06:08,784 but it's a little bit smaller than it. 131 00:06:08,784 --> 00:06:09,900 It's called a bacteriophage. 132 00:06:09,900 --> 00:06:11,547 This is good news for all of you. 133 00:06:11,547 --> 00:06:13,572 All of you non-scientists might not realize 134 00:06:13,572 --> 00:06:16,770 that these bacteria that make us sick 135 00:06:16,785 --> 00:06:19,590 they actually also get sick, they also have virus infections. 136 00:06:19,590 --> 00:06:23,767 The only organisms that gets away without being sick 137 00:06:23,767 --> 00:06:24,876 are the viruses themselves. 138 00:06:24,876 --> 00:06:27,059 But so, bacteria do get virus infections 139 00:06:27,059 --> 00:06:28,287 and they actually die from it 140 00:06:28,287 --> 00:06:30,270 and that's what these guys were studying. 141 00:06:30,270 --> 00:06:33,104 And they also wanted to look at this idea: 142 00:06:33,104 --> 00:06:35,739 is variation independent of selection. 143 00:06:35,739 --> 00:06:38,522 And they came up with a very smart experiment. 144 00:06:38,522 --> 00:06:42,717 What they did is, they said, "Well, let's start from one bacterial cell. 145 00:06:42,717 --> 00:06:45,593 And let's give it lot of food so it will make lots of little bacteria." 146 00:06:45,593 --> 00:06:46,912 And they always divide as you know, 147 00:06:46,912 --> 00:06:51,590 bacteria they grow or they multiply by just dividing themselves into two 148 00:06:51,590 --> 00:06:53,802 and they make clones of themselves, 149 00:06:53,802 --> 00:06:56,238 genetically identical, and so this is what happens. 150 00:06:56,238 --> 00:06:57,994 And they said -- 151 00:06:57,994 --> 00:07:00,807 so these are the bacteria here, always dividing -- 152 00:07:00,807 --> 00:07:04,079 and they said, "Well, at some point we're going to introduce a virus 153 00:07:04,079 --> 00:07:04,989 and we're going to see what happens." 154 00:07:04,989 --> 00:07:08,703 Because they've noted that when you introduce a virus to lots of bacteria 155 00:07:08,703 --> 00:07:12,282 there's always a few bacteria that manage to survive. 156 00:07:12,282 --> 00:07:18,821 They are genetically, because their little children bacteria are also surviving, 157 00:07:18,821 --> 00:07:20,631 so it's clearly a genetic trait 158 00:07:20,631 --> 00:07:23,394 something has happened to their DNA, to their genetic material. 159 00:07:23,394 --> 00:07:25,019 So something has happened. 160 00:07:25,019 --> 00:07:27,137 Some of these bacteria are resistant. 161 00:07:27,137 --> 00:07:28,649 And now the question is -- 162 00:07:28,649 --> 00:07:30,586 this variation, because that's what it is, 163 00:07:30,586 --> 00:07:35,811 does it occur before the bacteria are ever in contact with the virus? 164 00:07:35,811 --> 00:07:38,531 Or is it when we infect this culture, 165 00:07:38,531 --> 00:07:40,517 this hundred of millions of cells, 166 00:07:40,517 --> 00:07:43,805 that suddenly a few manage to become resistant? 167 00:07:43,805 --> 00:07:45,507 It's a very interesting question. 168 00:07:45,507 --> 00:07:47,336 And they were very smart. 169 00:07:47,336 --> 00:07:49,915 They said, "Well, supose there is a mechanism 170 00:07:49,915 --> 00:07:55,451 by which, when you infect the bacteria with the virus, 171 00:07:55,451 --> 00:07:58,326 it tries to become resistant some way. 172 00:07:58,326 --> 00:07:59,551 There's a mechanism. 173 00:07:59,551 --> 00:08:02,370 Then, if you do this to a hundred million cells, 174 00:08:02,370 --> 00:08:05,035 and you do it a few times to a hundred million cells, 175 00:08:05,035 --> 00:08:08,169 you sort of expect that a similar number of bacteria 176 00:08:08,169 --> 00:08:09,572 will always become resistant 177 00:08:09,572 --> 00:08:12,905 that manage to get there, right? The lucky few. 178 00:08:12,905 --> 00:08:17,458 Whereas, suppose that some bacteria become resistant 179 00:08:17,458 --> 00:08:20,417 while they're multiplying -- the blue dots here --, 180 00:08:20,417 --> 00:08:23,760 You can have vastly diferent numbers when you repeat this experiment. 181 00:08:23,760 --> 00:08:25,673 Because, what can happen is: 182 00:08:25,673 --> 00:08:30,943 here we have a bacterium that becomes resistant to the virus 183 00:08:30,943 --> 00:08:32,684 very late in the reproduction. 184 00:08:32,684 --> 00:08:34,570 And there's only one in this whole population 185 00:08:34,570 --> 00:08:37,009 that's resistant, that's not killed by the virus. 186 00:08:37,009 --> 00:08:40,212 Here though, you have what is called a jackpot event, 187 00:08:40,212 --> 00:08:43,772 and the name comes exactly from what you think it comes from. 188 00:08:43,772 --> 00:08:46,989 Very early in the reproduction of this first cell here 189 00:08:46,989 --> 00:08:48,592 one of two kids becomes -- 190 00:08:48,592 --> 00:08:51,506 or maybe the parent becomes resistant 191 00:08:51,506 --> 00:08:53,595 and it starts dividing. And now half of your culture -- 192 00:08:53,595 --> 00:08:55,600 but we're talking millions of cells here -- are resistant. 193 00:08:55,600 --> 00:08:57,517 So you have this huge variation. 194 00:08:57,517 --> 00:08:59,226 So they've done the experiment 195 00:08:59,226 --> 00:09:01,551 and what they found was this. 196 00:09:01,551 --> 00:09:02,996 And so they concluded: 197 00:09:02,996 --> 00:09:05,603 Clearly -- and they've shown this matematically -- 198 00:09:05,603 --> 00:09:08,387 clearly some bacteria in this population 199 00:09:08,387 --> 00:09:11,737 were resistant to a virus that they've never seen before. 200 00:09:11,737 --> 00:09:15,066 And again, variation must be independent of selection. 201 00:09:15,066 --> 00:09:17,438 Now, I would claim, and other people have claimed, 202 00:09:17,438 --> 00:09:22,291 that the experiment does contain a pretty serious flaw. 203 00:09:22,291 --> 00:09:24,731 And I'm not saying that they didn't deserve the Nobel Prize, 204 00:09:24,731 --> 00:09:27,986 at all, they definitely deserved it. 205 00:09:27,986 --> 00:09:30,749 But one problem with their experiment is clearly 206 00:09:30,749 --> 00:09:34,322 that, well, they introduce a deadly virus 207 00:09:34,322 --> 00:09:38,618 maybe the bacteria have a mechanism to develop resistance 208 00:09:38,618 --> 00:09:40,634 or tolerance to this virus, 209 00:09:40,634 --> 00:09:42,971 but not to one that kills them instantaneously. 210 00:09:42,971 --> 00:09:45,460 Maybe they should have used some milder stress, 211 00:09:45,460 --> 00:09:46,595 some milder selection. 212 00:09:46,595 --> 00:09:48,733 So that's the problem there. 213 00:09:48,733 --> 00:09:50,735 And then of course, later 214 00:09:50,735 --> 00:09:55,601 after Watson and Crick and Rosalind Franklin here 215 00:09:55,601 --> 00:09:57,267 discovered the structure of DNA 216 00:09:57,267 --> 00:10:00,442 and the whole molecular research started taking off 217 00:10:00,442 --> 00:10:03,382 we sort of put everything together of the evolution theory 218 00:10:03,382 --> 00:10:05,407 into what is called 'the new synthesis'. 219 00:10:05,407 --> 00:10:07,070 And that's sort of our current theory of evolution 220 00:10:07,070 --> 00:10:09,489 where you have changes in the DNA code 221 00:10:09,489 --> 00:10:11,705 that are more or less random, 222 00:10:11,705 --> 00:10:14,199 they are independent of selection 223 00:10:14,199 --> 00:10:15,736 and they give you diferences, 224 00:10:15,736 --> 00:10:17,836 that's what's causing all these differences between us 225 00:10:17,836 --> 00:10:22,593 and that's why some of us cannot get AIDS and most of us can. 226 00:10:22,593 --> 00:10:26,238 Which is true, by the way. 227 00:10:26,238 --> 00:10:29,351 And so this is pretty much our theory. 228 00:10:29,351 --> 00:10:34,055 Now, I don't want to end here. 229 00:10:34,055 --> 00:10:35,490 What we've seen is that 230 00:10:35,490 --> 00:10:37,870 more and more evidence is emerging that 231 00:10:37,870 --> 00:10:39,523 the story is a bit more complex. 232 00:10:39,523 --> 00:10:41,854 And maybe variation and selection 233 00:10:41,854 --> 00:10:48,268 are not so completely independent as some people believed. 234 00:10:48,268 --> 00:10:49,826 And I got to know about this 235 00:10:49,826 --> 00:10:51,827 while studying this year 236 00:10:51,827 --> 00:10:55,659 I did my PHD in a beer brewing lab. 237 00:10:55,659 --> 00:10:57,232 You know, it's one of the better places 238 00:10:57,232 --> 00:10:59,724 to start your research as a student. 239 00:10:59,724 --> 00:11:02,072 And I was stuying yeast cells, 240 00:11:02,072 --> 00:11:04,837 great genetic model organism by the way, 241 00:11:04,837 --> 00:11:06,346 so actually one of the frustrations I have 242 00:11:06,346 --> 00:11:09,331 is, try to be taking seriously by the people who need to fund you 243 00:11:09,331 --> 00:11:11,755 or at the conference, when you're working on beer. 244 00:11:11,755 --> 00:11:16,249 And you go like, "Trust me, I'm doing real serious genetic experimenting." 245 00:11:16,249 --> 00:11:19,268 Alright, so one of the things I was studying is 246 00:11:19,268 --> 00:11:21,259 yeast cells that are clumping together. 247 00:11:21,259 --> 00:11:22,320 It's called flocculation. 248 00:11:22,320 --> 00:11:24,744 So what you see here is a bunch of yeast cells 249 00:11:24,744 --> 00:11:29,049 that stick to each other and they settle out in this in this culture here. 250 00:11:29,049 --> 00:11:32,009 This is important for beer because it happens at the end of fermentation. 251 00:11:32,009 --> 00:11:35,007 This is what pretty much makes the difference between a clear beer, 252 00:11:35,007 --> 00:11:37,319 that doesn't have any yeast cells in it, 253 00:11:37,319 --> 00:11:41,176 and what we call a 'witbier' or a 'weizenbier' 254 00:11:41,176 --> 00:11:43,175 that has yeast cells still floating around in it. 255 00:11:43,175 --> 00:11:45,618 And we were trying to find the genetics of this. 256 00:11:45,618 --> 00:11:47,751 What we found is this one gene here 257 00:11:47,751 --> 00:11:50,287 flow one, which stands for flocculation one. 258 00:11:50,287 --> 00:11:54,017 It's a gene, and what is so special about this gene 259 00:11:54,017 --> 00:11:56,085 is that it contains a middle part 260 00:11:56,085 --> 00:11:57,613 that is extremely unstable. 261 00:11:57,613 --> 00:12:01,194 So this gene is of course made of DNA, like any gene. 262 00:12:01,194 --> 00:12:03,873 And the middle part of the DNA is extremely unstable. 263 00:12:03,873 --> 00:12:06,635 It changes much more than any other DNA. 264 00:12:06,635 --> 00:12:08,496 And what it is in particular 265 00:12:08,496 --> 00:12:11,712 is that it contains these things which are called 'tandem repeats'. 266 00:12:11,712 --> 00:12:15,889 It's pretty much a piece of DNA that's repeated time and time again. 267 00:12:15,889 --> 00:12:19,545 It's much longer than what you see here but you get the basic idea. 268 00:12:19,545 --> 00:12:20,937 And what makes it unstable is 269 00:12:20,937 --> 00:12:23,646 that the number of these repeats changes very quickly. 270 00:12:23,646 --> 00:12:25,346 Every time the DNA is copied 271 00:12:25,346 --> 00:12:30,055 you have a pretty high chance that the number will be different from what it was. 272 00:12:30,055 --> 00:12:32,043 This has been known for a long time 273 00:12:32,043 --> 00:12:35,700 except people don't really expected too much within genes. 274 00:12:35,700 --> 00:12:38,142 Usually you find these tandem repeats outside of genes. 275 00:12:38,142 --> 00:12:42,497 But here and in some other genes you find this. 276 00:12:42,497 --> 00:12:45,235 So, what you have here is a piece of DNA 277 00:12:45,235 --> 00:12:48,808 or a particular gene that's changing more rapidly than other genes. 278 00:12:48,808 --> 00:12:52,342 And in this case it means that flocculation is changing, 279 00:12:52,342 --> 00:12:56,442 so this characteristic of the yeast, this specific thing, 280 00:12:56,442 --> 00:12:58,010 compare it to a long neck, if you will, 281 00:12:58,010 --> 00:13:01,413 is changing more rapidly than some other properties of the yeast. 282 00:13:01,413 --> 00:13:06,147 Now if you think that this is 283 00:13:06,147 --> 00:13:08,409 -- well, this doesn't matter -- 284 00:13:08,409 --> 00:13:11,834 if you think that this is specific for yeast cells you are wrong. 285 00:13:11,834 --> 00:13:14,393 Pretty much around the same time we were publishing our story, 286 00:13:14,393 --> 00:13:17,221 there was a great story published about dogs. 287 00:13:17,221 --> 00:13:18,518 And I don't know if you've thought about this 288 00:13:18,518 --> 00:13:22,342 but dogs are some of the most variable creatures 289 00:13:22,342 --> 00:13:24,019 on the face of the Earth. 290 00:13:24,019 --> 00:13:26,428 Especially when it comes to their shape. 291 00:13:26,428 --> 00:13:27,843 Just look at, you know, 292 00:13:27,843 --> 00:13:31,536 this Chihuahua and this St. Bernard here. 293 00:13:31,536 --> 00:13:33,053 They're the same species. 294 00:13:33,053 --> 00:13:35,321 In principle. And I say 'in principle.' 295 00:13:35,321 --> 00:13:37,289 These things can breed. 296 00:13:37,289 --> 00:13:39,571 You just hope that the Chihuahua is not a female. 297 00:13:39,571 --> 00:13:43,300 (Laughter) 298 00:13:43,300 --> 00:13:47,412 Now, these are bred by humans. 299 00:13:47,412 --> 00:13:49,513 We have made these dogs by selection and whatever. 300 00:13:49,513 --> 00:13:52,040 But we didn't even use so much time for it. 301 00:13:52,040 --> 00:13:55,772 And in evolutionary terms these things are new. 302 00:13:55,772 --> 00:13:58,040 They are brand new and they were, sort of -- 303 00:13:58,040 --> 00:14:00,463 they developed in a very short time. 304 00:14:00,463 --> 00:14:02,414 And one of the things that was found 305 00:14:02,414 --> 00:14:05,545 is that one of the key regulators that regulates -- 306 00:14:05,545 --> 00:14:07,883 and again I'm talking about the gene -- 307 00:14:07,883 --> 00:14:14,056 it's a regulating gene and it regulates the shape of the skull. 308 00:14:14,059 --> 00:14:15,995 Basically the shape of the dog as well. 309 00:14:15,995 --> 00:14:18,716 And it also has this unstable tandem repeats in it. 310 00:14:18,716 --> 00:14:20,929 And what these researchers found is 311 00:14:20,929 --> 00:14:22,815 that there's a nice correlation between 312 00:14:22,815 --> 00:14:25,302 how many repeats you have in this gene 313 00:14:25,302 --> 00:14:28,049 and how curved your snout is 314 00:14:28,049 --> 00:14:30,998 or how long your snout is. 315 00:14:30,998 --> 00:14:34,818 And they also found that some other changes in another regulatory gene 316 00:14:34,818 --> 00:14:37,188 give you a sixth finger. 317 00:14:37,188 --> 00:14:41,118 Sort of this little extra thumb here. 318 00:14:41,118 --> 00:14:43,603 And, I didn't know this but this is a characteristic 319 00:14:43,603 --> 00:14:47,352 of a specific breed of Great Dane dogs. 320 00:14:47,352 --> 00:14:50,539 And that's why this actually happened. 321 00:14:50,539 --> 00:14:51,986 It sort of happened in a very short time 322 00:14:51,986 --> 00:14:55,423 and now people see this sixt claw, if you will, 323 00:14:55,423 --> 00:14:57,380 as a characteristic. 324 00:14:57,380 --> 00:15:00,299 So clearly it's not just happening in yeast. 325 00:15:00,299 --> 00:15:02,279 And there's more. 326 00:15:02,279 --> 00:15:04,863 One of the other things that people have known for a while 327 00:15:04,863 --> 00:15:06,250 and we are also researching 328 00:15:06,250 --> 00:15:07,814 is that the end of chromosomes 329 00:15:07,814 --> 00:15:10,391 -- chromosomes are basically packages of DNA, 330 00:15:10,391 --> 00:15:12,226 that's how our DNA sits in the cell -- 331 00:15:12,226 --> 00:15:14,622 well, the ends of chromosomes -- here, 332 00:15:14,622 --> 00:15:17,320 the very ends -- they change much more quickly. 333 00:15:17,320 --> 00:15:19,075 There's higher mutation rates. 334 00:15:19,075 --> 00:15:20,501 The DNA is not as stable. 335 00:15:20,501 --> 00:15:23,580 And so the genes that lie there, again, evolve. 336 00:15:23,580 --> 00:15:27,207 And if you're wondering in humans which genes are lying there. 337 00:15:27,207 --> 00:15:29,612 It's the genes that, for example, 338 00:15:29,612 --> 00:15:31,638 the genes that make us smell. 339 00:15:31,638 --> 00:15:33,600 And of course we have to recognize lots of different smells 340 00:15:33,600 --> 00:15:35,450 and these genes are copying themselves 341 00:15:35,450 --> 00:15:40,167 and they are changing very quickly. 342 00:15:40,167 --> 00:15:42,443 In plants: a whole different mechanism. 343 00:15:42,443 --> 00:15:43,872 And this is a bit more complicated. 344 00:15:43,872 --> 00:15:46,650 I will try to fly through it. 345 00:15:46,650 --> 00:15:48,869 There's this particular protein. 346 00:15:48,869 --> 00:15:51,276 And, this is a bit like your mother. 347 00:15:51,276 --> 00:15:53,021 This protein is the mother of the cell. 348 00:15:53,021 --> 00:15:54,861 It sort of checks all the other little proteins 349 00:15:54,861 --> 00:15:57,317 and it goes like, "Are you okay? 350 00:15:57,317 --> 00:15:59,942 You don't look very good. Here, here's your coat. 351 00:15:59,942 --> 00:16:01,731 You should behave this way, don't behave that way." 352 00:16:01,731 --> 00:16:03,738 It's sort of like a teacher mother. 353 00:16:03,738 --> 00:16:05,843 And, so the protein really takes care 354 00:16:05,843 --> 00:16:07,819 that even if there's small mutations, 355 00:16:07,819 --> 00:16:10,336 changes in other proteins, that they still behave right. 356 00:16:10,336 --> 00:16:13,059 And if they don't behave right, they get degraded. 357 00:16:13,059 --> 00:16:15,315 Now what you see is that, in times of stress 358 00:16:15,315 --> 00:16:17,226 -- and plants also have stress, 359 00:16:17,226 --> 00:16:20,349 stress is a biological word for selection. 360 00:16:20,349 --> 00:16:23,961 It means you're not adapted to a condition. 361 00:16:23,961 --> 00:16:27,457 It means that you feel the burden of evolution 362 00:16:27,457 --> 00:16:29,481 pressing down on you, pretty much. 363 00:16:29,481 --> 00:16:33,688 So, in times of stress, this protein, this function of the mother protein, 364 00:16:33,688 --> 00:16:36,157 gets dialed down a little bit. 365 00:16:36,157 --> 00:16:39,240 And suddenly these plants start disbehaving. 366 00:16:39,240 --> 00:16:40,710 You know, they become weird. 367 00:16:40,710 --> 00:16:43,939 And that's because some mutations that you previously couldn't see 368 00:16:43,939 --> 00:16:46,177 now suddenly emerge. 369 00:16:46,177 --> 00:16:48,269 And, although it's not proven, it seems like a likely theory 370 00:16:48,269 --> 00:16:50,260 that maybe this could serve as a mechanism 371 00:16:50,260 --> 00:16:52,222 to try and escape the stress. 372 00:16:52,222 --> 00:16:54,383 Because suddenly it's good to try and be different 373 00:16:54,383 --> 00:16:56,748 from what your mother was. 374 00:16:56,748 --> 00:16:58,859 And so maybe a few of these plants 375 00:16:58,859 --> 00:17:00,576 are better at surviving the stress. 376 00:17:00,576 --> 00:17:03,083 And they will cope. And maybe this mutation can get fixed. 377 00:17:03,083 --> 00:17:05,746 And this and that. 378 00:17:05,746 --> 00:17:09,649 Another thing, another example comes from bacteria. 379 00:17:09,649 --> 00:17:11,421 And I'm just skimming over it again, 380 00:17:11,421 --> 00:17:16,224 but bacteria -- in times of stress, again 381 00:17:16,224 --> 00:17:19,963 they activate -- and this is just to impress you 382 00:17:19,963 --> 00:17:22,633 it's not very important -- in times of stress 383 00:17:22,633 --> 00:17:27,535 what they do is, they activate a different protein to copy their DNA. 384 00:17:27,535 --> 00:17:30,253 And of course a protein to copy your DNA is a very important protein. 385 00:17:30,253 --> 00:17:31,998 Because it shouldn't make too many mistakes. 386 00:17:31,998 --> 00:17:34,983 Because that's how you get changes in DNA 387 00:17:34,983 --> 00:17:36,613 and that's how you get natural variation. 388 00:17:36,613 --> 00:17:39,227 So you need a little bit of them but you don't want to much of them 389 00:17:39,227 --> 00:17:42,298 because most of the variation is not good. 390 00:17:42,298 --> 00:17:45,867 It wouldn't be so great if a giraffe got a neck that was three times as long 391 00:17:45,867 --> 00:17:49,873 because the heart couldn't cope with it. 392 00:17:49,873 --> 00:17:51,824 But in times of stress, again 393 00:17:51,824 --> 00:17:54,885 it's obvious sometimes you need to chose between dying or gambling. 394 00:17:54,885 --> 00:17:56,454 And bacteria may be gambling. 395 00:17:56,454 --> 00:17:59,711 They activate this gene that's very sloppy. 396 00:17:59,711 --> 00:18:02,983 And so the DNA gets copied, but it has lots more changes in it. 397 00:18:02,983 --> 00:18:05,444 And maybe, although it's hard to prove it, 398 00:18:05,444 --> 00:18:09,358 maybe this is a strategy of bacteria to try and beat the selection, 399 00:18:09,358 --> 00:18:14,413 the evolutionary pressure that's pushing down on them. 400 00:18:14,413 --> 00:18:18,253 An even nicer example, I think, is the waterflea here. 401 00:18:18,253 --> 00:18:20,684 Again, it's pretty mysterious still. 402 00:18:20,684 --> 00:18:24,643 But waterfleas, swimming around, beautiful organisms, 403 00:18:24,643 --> 00:18:27,327 they have predators. And when they get -- you know, 404 00:18:27,327 --> 00:18:31,595 there's a family of waterfleas and dad gets eaten, 405 00:18:31,595 --> 00:18:34,057 there's some chemicals released in the water 406 00:18:34,057 --> 00:18:39,084 and it induces the formation of the stickle here, which is called a 'spina'. 407 00:18:39,084 --> 00:18:43,318 And the stickle makes the waterflea a little bit less attractive for predators. 408 00:18:43,318 --> 00:18:45,256 Now that's all great, thats not so special 409 00:18:45,256 --> 00:18:47,581 a chemical induces some morphological change. 410 00:18:47,581 --> 00:18:52,764 The weird thing is that the kids of this waterflea will also have the spina. 411 00:18:52,764 --> 00:18:54,601 Even if they've never seen a predator. 412 00:18:54,601 --> 00:18:56,408 Even if you take all the predators away. 413 00:18:56,408 --> 00:18:58,942 They will still have this for quite a while, 414 00:18:58,942 --> 00:19:00,790 for a few generations. 415 00:19:00,790 --> 00:19:03,706 So this comes very close to Lamarck, right? 416 00:19:03,706 --> 00:19:06,498 There is something happening in the course of the life of this organism. 417 00:19:06,498 --> 00:19:12,056 It changes something and it's giving that information to its kids. 418 00:19:12,056 --> 00:19:14,620 It's getting pretty close to Lamarck. 419 00:19:14,620 --> 00:19:20,001 So, this is, the conclusion of the talk -- and this is important -- 420 00:19:20,001 --> 00:19:24,288 does this mean that our theory of evolution really needs a major overhaul? 421 00:19:24,288 --> 00:19:25,445 I would say: not at all. 422 00:19:25,445 --> 00:19:28,465 And, people have often misunderstood 423 00:19:28,465 --> 00:19:30,290 I guess the things I have said and published. 424 00:19:30,290 --> 00:19:35,194 And it happened recently in this Flemish, or Dutch, magazine here, where I wrote a piece 425 00:19:35,194 --> 00:19:38,801 telling, or writing about the same things that I'm telling you now. 426 00:19:38,801 --> 00:19:40,898 And this is the cover they came up with. 427 00:19:40,898 --> 00:19:46,033 I wasn't so happy because it looks like I'm sort of sawing the ground under Darwin. 428 00:19:46,033 --> 00:19:47,449 No. 429 00:19:47,449 --> 00:19:49,578 Here, this is what Darwin wrote literally 430 00:19:49,578 --> 00:19:51,378 about variation and selection. 431 00:19:51,378 --> 00:19:53,326 He says, pretty much he says, 432 00:19:53,326 --> 00:19:58,293 I have spoken as if this natural variation was totally random in my book. 433 00:19:58,293 --> 00:20:01,081 Like it was just pure chance. 434 00:20:01,081 --> 00:20:04,341 But of course I didn't mean to imply that. 435 00:20:04,341 --> 00:20:06,400 It just means that I don't really know what's happening. 436 00:20:06,400 --> 00:20:08,956 And maybe there is a mechanism It's much more complex. 437 00:20:08,956 --> 00:20:11,292 Darwin was extremely clever. He thought about his theory. 438 00:20:11,292 --> 00:20:13,463 He knew exactly where the holes were 439 00:20:13,463 --> 00:20:17,167 and where he shouldn't really speak for one possibility or the other. 440 00:20:17,167 --> 00:20:18,578 So he actually incorporated -- 441 00:20:18,578 --> 00:20:22,462 it's only later that maybe we've gone a bit too far away from Lamarck. 442 00:20:22,462 --> 00:20:25,276 He didn't really dislike Lamarck's theory that much. 443 00:20:25,276 --> 00:20:29,279 Although, this is not to say that Lamarck's theory was right. 444 00:20:29,279 --> 00:20:32,000 I mean, I still think that it's mostly random 445 00:20:32,000 --> 00:20:34,545 but there's some small changes here and there 446 00:20:34,545 --> 00:20:37,738 that make it a little less random than completely random. 447 00:20:37,738 --> 00:20:40,951 So, what I'm saying is that through evolution, mechanisms 448 00:20:40,951 --> 00:20:47,722 have developed that make evolution not a complete chance. 449 00:20:47,722 --> 00:20:49,465 And then you might start wondering 450 00:20:49,465 --> 00:20:51,280 how can this be right. 451 00:20:51,280 --> 00:20:54,797 And there I would argue this just happens through the process of evolution. 452 00:20:54,797 --> 00:20:58,572 Suppose a gene becomes very unstable 453 00:20:58,572 --> 00:21:00,201 and it's a housekeeping gene 454 00:21:00,201 --> 00:21:02,476 it's a gene that doesn't need to change. 455 00:21:02,476 --> 00:21:04,980 Or it doesn't need to change as quickly. 456 00:21:04,980 --> 00:21:07,603 Or when it changes it's mostly detrimental. 457 00:21:07,603 --> 00:21:09,710 Now, if such a gene becomes unstable 458 00:21:09,710 --> 00:21:12,762 it's going to be a huge disadvantage for the organism that has it. 459 00:21:12,762 --> 00:21:14,748 And so it will be selected away. 460 00:21:14,748 --> 00:21:16,867 However, if a gene 461 00:21:16,867 --> 00:21:21,265 for example, a gene that makes your skull a bit more flexible, 462 00:21:21,265 --> 00:21:23,480 like in a giraffe, and maybe you can, you know, 463 00:21:23,480 --> 00:21:26,061 you get more giraffes with longer necks. 464 00:21:26,061 --> 00:21:29,132 If such a gene arises, by pure chance -- 465 00:21:29,132 --> 00:21:31,344 and this is pure chance. 466 00:21:31,344 --> 00:21:35,101 Maybe it becomes an advantage for the organism and it stays there. 467 00:21:35,104 --> 00:21:37,930 It stays unstable like it was. 468 00:21:37,930 --> 00:21:41,866 And maybe that's how these things have evolved. 469 00:21:41,866 --> 00:21:45,143 Now again, like I said, my work sometimes gets misinterpreted. 470 00:21:45,143 --> 00:21:48,052 Sometimes it's quite funny. Especially when it's the people 471 00:21:48,052 --> 00:21:52,496 that believe in creationism as a more intelligent design that take our work. 472 00:21:52,496 --> 00:21:54,800 This was [one of] the more funny things. 473 00:21:54,800 --> 00:21:57,607 This is a website called 'uncommon descent.' 474 00:21:57,607 --> 00:21:59,356 And if you think about it, you know, 475 00:21:59,356 --> 00:22:02,294 the title says it all. These people don't believe in the common descent, 476 00:22:02,294 --> 00:22:05,826 that's of course at core of our evolution theory. 477 00:22:05,826 --> 00:22:08,076 So we published a paper, 478 00:22:08,076 --> 00:22:12,815 a coleague in the U.S. -- when I was still working in the U.S. -- and I. 479 00:22:12,815 --> 00:22:17,650 And we were, again in this paper, it's a more in-depth discussion of what I'm telling you know, 480 00:22:17,650 --> 00:22:21,994 and we were aware of the fact that some people might misinterpret this. 481 00:22:21,994 --> 00:22:25,506 So, in the abstract, in the summary of the paper, 482 00:22:25,506 --> 00:22:28,220 which is pretty much the thing that everybody will read, 483 00:22:28,220 --> 00:22:34,297 we wrote, specifically, that our ideas do not go against Darwin. 484 00:22:34,297 --> 00:22:37,685 And then these guys here read the article, 485 00:22:37,685 --> 00:22:39,329 still wanted to use it for their ideas. 486 00:22:39,329 --> 00:22:45,062 And they said, "Well, to publish this in a reputed scientific journal 487 00:22:45,062 --> 00:22:48,815 the authors needed to write something that their ideas do not go against Darwin, 488 00:22:48,815 --> 00:22:50,117 but they don't mean it. 489 00:22:50,117 --> 00:22:54,301 It's just a secret handshake to get into this good journal." 490 00:22:54,301 --> 00:22:56,662 So that's the secret handshake here. 491 00:22:56,662 --> 00:22:57,903 So luckily there was -- 492 00:22:57,903 --> 00:23:01,780 oh, then it becomes quite funny because there's reactions on this forum 493 00:23:01,780 --> 00:23:08,236 of people, and, well, I can barely read it myself, but I'll try. 494 00:23:08,236 --> 00:23:11,068 So this is one of the people reacting to this, and he says -- 495 00:23:11,068 --> 00:23:14,303 they quote some of the parts that we write in the paper -- 496 00:23:14,303 --> 00:23:18,396 and he says like: "Error-prone DNA copying enzymes 497 00:23:18,396 --> 00:23:22,227 produce bursts of variability in times of stress. 498 00:23:22,227 --> 00:23:26,979 These mechanisms seem to tune the variability of a given characteristic 499 00:23:26,979 --> 00:23:30,479 to match the variability of the selection." 500 00:23:30,479 --> 00:23:32,842 That's something that we wrote. 501 00:23:32,842 --> 00:23:36,518 And he says, "Gee, it almost seems like a built-in response mechanism. 502 00:23:36,518 --> 00:23:41,350 Who would've thunk. Darwin is sooo dead!" That's what he writes. 503 00:23:41,350 --> 00:23:44,540 Anyway, so there's some people who did not misunderstand our paper 504 00:23:44,540 --> 00:23:46,096 and they reacted to this. 505 00:23:46,096 --> 00:23:47,502 And it's also fun to read this discussion 506 00:23:47,502 --> 00:23:50,821 because then the 'intelligent design' people get on. 507 00:23:50,821 --> 00:23:52,214 It's all one great family. 508 00:23:52,214 --> 00:23:54,755 It's kind of fun to have this -- I really like these discussions. 509 00:23:54,755 --> 00:23:59,183 I have nothing against people who come up with different theories. 510 00:23:59,183 --> 00:24:01,022 They're just wrong, but, you know, 511 00:24:01,022 --> 00:24:03,687 it makes it fun to discuss with them. 512 00:24:03,687 --> 00:24:07,298 Alright, this brings me to the acknowledgements. 513 00:24:07,298 --> 00:24:09,903 And I have to acknowledge pretty much all these people here, 514 00:24:09,903 --> 00:24:12,481 which are the people who are doing all the hard working in my lab, 515 00:24:12,481 --> 00:24:14,717 probably as we're speaking now they're getting more results 516 00:24:14,717 --> 00:24:19,299 so I can give another great talk and, you know, be the hero for this audience. 517 00:24:19,299 --> 00:24:22,273 They are chained to their benches. 518 00:24:22,273 --> 00:24:24,332 I have to remember to feed them tonight. 519 00:24:24,332 --> 00:24:27,906 But, they really are the heroes of the lab. 520 00:24:27,906 --> 00:24:29,307 And there are many more of them, of course, 521 00:24:29,307 --> 00:24:32,502 our group is definitely not the only one doing this work. 522 00:24:32,502 --> 00:24:35,224 For people who are scientists and want to know more about this 523 00:24:35,224 --> 00:24:36,751 these are some of the publications. 524 00:24:36,751 --> 00:24:40,172 This is the major one, where we really sort of discuss all these things. 525 00:24:40,172 --> 00:24:41,966 There's more information on the website. 526 00:24:41,966 --> 00:24:43,624 And this is very impotant as well, 527 00:24:43,624 --> 00:24:46,164 these are the people that are paying us. 528 00:24:46,164 --> 00:24:48,185 Well not me, but, more, the research. 529 00:24:48,185 --> 00:24:49,876 Thanks.