1 00:00:11,277 --> 00:00:12,637 Good evening. 2 00:00:12,814 --> 00:00:16,512 Here you see a little petri dish that we use in the lab 3 00:00:16,512 --> 00:00:19,543 with a dry leaf, completely dry, 4 00:00:19,543 --> 00:00:21,805 and on there, there are females. 5 00:00:22,055 --> 00:00:24,007 Why do I say females? 6 00:00:24,007 --> 00:00:28,415 Because that's their way of life: They live and evolve without males; 7 00:00:28,415 --> 00:00:30,525 they got rid of males. 8 00:00:30,595 --> 00:00:32,476 And also, they are dry. 9 00:00:32,476 --> 00:00:35,586 They can dry up, and we can wait for years, 10 00:00:35,586 --> 00:00:38,505 put them in the freezer, and get them back. 11 00:00:38,505 --> 00:00:42,636 Tonight we will do a live experiment with one of my scientists, Boris, 12 00:00:42,636 --> 00:00:44,986 to resurrect these animals for you, 13 00:00:44,986 --> 00:00:46,497 these females. 14 00:00:48,357 --> 00:00:49,543 Thanks, Boris. 15 00:00:51,523 --> 00:00:53,395 So look around you. 16 00:00:53,745 --> 00:00:57,813 There is an amazing diversity of living organisms on this planet, 17 00:00:57,813 --> 00:01:02,001 from bacteria to fungi to plants to animals to human - 18 00:01:02,171 --> 00:01:04,213 nothing looks alike. 19 00:01:04,553 --> 00:01:11,192 But do you know that all this diversity arose once from a universal ancestor 20 00:01:11,192 --> 00:01:14,182 around 3.5 billion years ago? 21 00:01:14,182 --> 00:01:18,964 And this ancestor of all living organisms was a single simple cell, 22 00:01:18,964 --> 00:01:21,103 something like a bacterium. 23 00:01:21,453 --> 00:01:26,376 But how do we know that all life has evolved from a single cell? 24 00:01:27,030 --> 00:01:31,137 We know this because we all share the same alphabet; 25 00:01:31,137 --> 00:01:34,015 we have the same DNA code. 26 00:01:34,186 --> 00:01:37,507 DNA is a magical molecule of life. 27 00:01:37,604 --> 00:01:42,870 And DNA is only made up of four chemical building blocks: 28 00:01:43,683 --> 00:01:46,735 cytosine, guanine, adenine, thymine. 29 00:01:46,735 --> 00:01:51,465 So only four letters that make the whole alphabet of life. 30 00:01:52,167 --> 00:01:57,606 So yes, from bacteria to human, we only need four letters, 31 00:01:58,543 --> 00:02:03,462 but then, what's our DNA instruction book looking like? 32 00:02:03,853 --> 00:02:08,892 In each of our cells, we have around three billion of those letters, 33 00:02:08,892 --> 00:02:12,174 organized on 23 pairs of chromosomes. 34 00:02:12,233 --> 00:02:13,243 So you see here, 35 00:02:13,243 --> 00:02:15,583 it's a compaction of these four letters. 36 00:02:15,583 --> 00:02:20,903 But what makes you different from me is that these letters change. 37 00:02:21,182 --> 00:02:24,855 These letters change between all these individuals. 38 00:02:25,444 --> 00:02:30,527 So if we all have the same genetic code, it means we are all related. 39 00:02:30,616 --> 00:02:31,615 Yes, we are. 40 00:02:31,615 --> 00:02:34,018 We are all cousins from each other. 41 00:02:34,486 --> 00:02:36,196 But then, you may wonder: 42 00:02:36,196 --> 00:02:39,601 How did we evolve to so many complex forms 43 00:02:39,601 --> 00:02:43,006 from such a single cell a long time ago? 44 00:02:43,435 --> 00:02:48,096 And that's when I want you to remember the card game we have been playing. 45 00:02:48,266 --> 00:02:52,746 What's essential for evolution is genetic variation, 46 00:02:52,746 --> 00:02:55,123 its changes in these letters. 47 00:02:55,123 --> 00:02:58,565 So these letters change randomly. 48 00:02:58,895 --> 00:03:01,595 And most of these changes are neutral, 49 00:03:01,595 --> 00:03:05,323 they have no effect on the fitness of the individual, 50 00:03:05,323 --> 00:03:08,930 but if a change is an advantage, it can be selected. 51 00:03:08,930 --> 00:03:09,950 Remember? 52 00:03:09,950 --> 00:03:13,098 We select if a positive mutation appears. 53 00:03:13,098 --> 00:03:14,269 Why is it selected? 54 00:03:14,269 --> 00:03:16,761 Because the individual gets an advantage 55 00:03:16,761 --> 00:03:19,161 and it might reproduce more than the others 56 00:03:19,161 --> 00:03:21,459 so the mutation is transmitted. 57 00:03:22,141 --> 00:03:23,420 And we know 58 00:03:23,638 --> 00:03:26,039 that natural selection is cumulative, 59 00:03:26,039 --> 00:03:28,640 that we can accumulate this positive mutation, 60 00:03:28,640 --> 00:03:31,860 which is important for adaptation and evolution. 61 00:03:32,016 --> 00:03:34,232 So as I said, during the card game, 62 00:03:34,232 --> 00:03:38,602 there is nothing of intelligence or a creator out there 63 00:03:38,602 --> 00:03:40,373 for evolution. 64 00:03:40,996 --> 00:03:42,832 And look at cancer development. 65 00:03:42,842 --> 00:03:45,894 Cancer development is also an evolutionary process; 66 00:03:45,894 --> 00:03:48,206 it follows this same mechanism. 67 00:03:48,206 --> 00:03:53,752 Each of our cells accumulate randomly these changes, these mutations, 68 00:03:53,783 --> 00:03:58,203 but if one of these normal cells suddenly gets a growth advantage - 69 00:03:58,203 --> 00:04:01,861 a mutation that gives it a growth advantage compared to the other cells - 70 00:04:01,861 --> 00:04:04,690 it will start to grow quicker - 71 00:04:04,690 --> 00:04:06,519 an uncontrolled proliferation - 72 00:04:06,519 --> 00:04:08,621 and cancer can occur. 73 00:04:08,811 --> 00:04:10,669 And of course, it's a problem to human. 74 00:04:10,669 --> 00:04:12,010 We know it. 75 00:04:12,019 --> 00:04:14,720 But you know, animals also get cancer. 76 00:04:14,949 --> 00:04:17,321 But do all of them get cancer? 77 00:04:18,044 --> 00:04:22,201 There are a few mysterious species that don't develop cancer. 78 00:04:22,959 --> 00:04:24,119 What are they? 79 00:04:24,119 --> 00:04:27,230 The most notorious one is this naked mole rat. 80 00:04:27,269 --> 00:04:29,070 Very cute animal, no? 81 00:04:29,070 --> 00:04:30,071 (Laughter) 82 00:04:30,071 --> 00:04:32,794 For scientists, it's a very interesting animal. 83 00:04:32,794 --> 00:04:35,182 It's very small. It's like a mouse. 84 00:04:35,344 --> 00:04:39,314 But it lives for 30 years, and a mouse lives for four years. 85 00:04:39,364 --> 00:04:40,972 What's also interesting is 86 00:04:40,972 --> 00:04:43,708 if you inject the cancer cell in this animal, 87 00:04:43,708 --> 00:04:45,653 it will not develop. 88 00:04:45,793 --> 00:04:46,932 And why? 89 00:04:47,165 --> 00:04:49,177 Scientists have searched for this for years 90 00:04:49,177 --> 00:04:51,429 and found that they have this kind of molecule - 91 00:04:51,429 --> 00:04:53,813 a high molecular mass, hyaluronan; 92 00:04:53,813 --> 00:04:56,633 it's a kind of super sugar - 93 00:04:56,633 --> 00:04:59,903 that is secreted around the cells of these animals, 94 00:05:00,003 --> 00:05:02,924 and it makes their tissue very elastic. 95 00:05:02,924 --> 00:05:04,084 And why is it important? 96 00:05:04,084 --> 00:05:08,366 Because these animals dig into the soil, they make these burrows, 97 00:05:08,366 --> 00:05:10,658 and so their tissue needs to be very elastic. 98 00:05:10,658 --> 00:05:12,529 So it's an adaptation to this. 99 00:05:12,529 --> 00:05:14,109 But what's interesting 100 00:05:14,109 --> 00:05:17,659 is that this molecule, when it's secreted around the cell, 101 00:05:17,659 --> 00:05:21,319 prevents the cell from dividing or proliferating further. 102 00:05:21,599 --> 00:05:22,896 So you immediately see 103 00:05:22,896 --> 00:05:26,786 the interesting application of the discovery of such a molecule. 104 00:05:27,073 --> 00:05:30,134 But if you think this is the only interesting animal out there, 105 00:05:30,134 --> 00:05:31,375 you’re wrong. 106 00:05:31,435 --> 00:05:36,486 Nature is full of mysterious species, where we can discover so much. 107 00:05:36,666 --> 00:05:41,444 Nature has been an inspiration to scientists for so many years. 108 00:05:41,454 --> 00:05:43,523 Like Albert Einstein said, 109 00:05:43,563 --> 00:05:49,421 "We know less than one thousandth of 1% of what nature has to reveal to us." 110 00:05:49,461 --> 00:05:51,724 And if we start to destroy our nature, 111 00:05:51,724 --> 00:05:55,264 we will not even discover everything that's out there. 112 00:05:55,352 --> 00:05:56,942 Look at this gecko. 113 00:05:57,163 --> 00:06:02,638 This gecko, we know, can run quickly on vertical glass. 114 00:06:02,808 --> 00:06:03,819 But how? 115 00:06:03,819 --> 00:06:07,970 How can these animals adhere so strongly to glass 116 00:06:07,970 --> 00:06:09,910 and then just run on it? 117 00:06:09,920 --> 00:06:10,919 And so, for long, 118 00:06:10,919 --> 00:06:12,700 scientists looked at the molecule: 119 00:06:12,700 --> 00:06:16,813 What kind of molecule is secreted that makes them like a glue, 120 00:06:16,813 --> 00:06:18,790 like a strong adhesion? 121 00:06:18,950 --> 00:06:21,209 And in fact, by looking at these fingers, 122 00:06:21,209 --> 00:06:24,223 they found there's nothing of a molecule that is secreted, 123 00:06:24,223 --> 00:06:25,833 but it's a structure. 124 00:06:25,833 --> 00:06:27,384 What they discovered 125 00:06:27,384 --> 00:06:31,925 is that underneath these fingers, there are these hair-like structures, 126 00:06:31,925 --> 00:06:33,354 millions of them. 127 00:06:33,354 --> 00:06:36,134 And if you look even at the nanoscopic level, 128 00:06:36,134 --> 00:06:38,273 you see that at the end of all of these hairs, 129 00:06:38,273 --> 00:06:42,512 you have hundreds of these spatula-likes structures. 130 00:06:42,633 --> 00:06:45,013 And when these are in strong contact with glass, 131 00:06:45,013 --> 00:06:49,449 it creates a strong adhesion just through simple Van der Waals forces, 132 00:06:49,449 --> 00:06:52,672 the simple forces that make this strong adhesion. 133 00:06:52,672 --> 00:06:55,734 And when they rotate their fingers, 134 00:06:55,734 --> 00:07:00,270 this force releases immediately and they can run further. 135 00:07:00,270 --> 00:07:01,251 And of course, 136 00:07:01,271 --> 00:07:05,430 laboratories have now been interested to reconstruct these nano-structures 137 00:07:05,430 --> 00:07:08,130 to make strong adhesives. 138 00:07:08,590 --> 00:07:10,481 And that's what I want to show you: 139 00:07:10,481 --> 00:07:14,528 It's so interesting to study biology because there's so much to discover, 140 00:07:14,528 --> 00:07:17,060 because there has been such a long evolution 141 00:07:17,060 --> 00:07:21,659 of all kinds of specimens with all kinds of different adaptations. 142 00:07:22,179 --> 00:07:24,803 And what has puzzled me is reproduction. 143 00:07:24,803 --> 00:07:27,853 You know that for life, it's essential to reproduce; 144 00:07:28,183 --> 00:07:31,443 we need to reproduce or the species will go extinct. 145 00:07:31,443 --> 00:07:34,213 But do you know that sexual reproduction, 146 00:07:34,213 --> 00:07:35,873 the one we all know, 147 00:07:35,873 --> 00:07:38,764 is the queen of problems in evolutionary biology? 148 00:07:38,764 --> 00:07:41,304 For us scientists, it's really a puzzle. 149 00:07:41,643 --> 00:07:43,022 And why? 150 00:07:43,142 --> 00:07:47,104 Think about all the energy you need to spend to find a partner, 151 00:07:47,104 --> 00:07:49,864 all the strategies the male's developed 152 00:07:49,864 --> 00:07:53,654 to try to attract a female, to try to fertilize her, 153 00:07:54,074 --> 00:07:57,160 to the point that there is a battle of sexes. 154 00:07:57,160 --> 00:07:58,556 Believe me - 155 00:07:58,929 --> 00:08:02,740 a man penis is boring compared to this insect penis. 156 00:08:02,740 --> 00:08:05,010 This is a penis of a bean weevil, 157 00:08:05,010 --> 00:08:06,720 full of spines, 158 00:08:06,753 --> 00:08:11,891 and the males with the longest spines are those that fertilize most of the eggs. 159 00:08:12,102 --> 00:08:14,960 Of course, the female cannot reproduce anymore afterwards, 160 00:08:14,960 --> 00:08:18,770 but at least, the male is sure he has transmitted his genes. 161 00:08:19,170 --> 00:08:20,744 A look at this fruit fly. 162 00:08:20,744 --> 00:08:24,613 You might have many fruit flies in summer around your trash bin. 163 00:08:24,963 --> 00:08:27,618 This fruit fly, Drosophila bifurca, 164 00:08:27,618 --> 00:08:32,033 produces giant sperm, 20 times its body size. 165 00:08:32,033 --> 00:08:33,035 It's like, you men, 166 00:08:33,035 --> 00:08:36,753 you would have a sperm that is twenty times your body size, 167 00:08:36,753 --> 00:08:38,648 like a building of 12 stories. 168 00:08:38,648 --> 00:08:39,684 (Laughter) 169 00:08:39,684 --> 00:08:40,873 Wow! 170 00:08:41,134 --> 00:08:44,583 But at least, when it transmits this to the female, 171 00:08:44,703 --> 00:08:47,123 the receptacle of the female is filled, 172 00:08:47,123 --> 00:08:49,932 there is no space for another sperm, 173 00:08:49,932 --> 00:08:52,526 so it's sure to transmit its genes. 174 00:08:53,013 --> 00:08:56,876 But then, why did such a complicated mode of reproduction evolve? 175 00:08:56,876 --> 00:08:58,790 And why is it so omnipresent? 176 00:08:58,790 --> 00:09:01,021 Is it not just simpler to clone yourself? 177 00:09:01,021 --> 00:09:03,729 One individual makes a new individual? 178 00:09:04,221 --> 00:09:08,940 So why is sexual reproduction so prevalent in nature? 179 00:09:09,550 --> 00:09:11,690 In fact, for us biologists, 180 00:09:11,789 --> 00:09:17,049 sex is just about mixing genetic material of one individual with another individual 181 00:09:17,209 --> 00:09:21,719 to create each generation of offsprings that are all different. 182 00:09:21,809 --> 00:09:24,374 And that's a force of sexual reproduction: 183 00:09:24,374 --> 00:09:28,843 It creates every generation this genetic variability 184 00:09:28,843 --> 00:09:31,203 that is essential for evolution. 185 00:09:31,350 --> 00:09:35,112 So does it mean that animals that lose sexual reproduction 186 00:09:35,112 --> 00:09:37,682 or that abandon it or have no sexual reproduction 187 00:09:37,702 --> 00:09:40,113 cannot evolve, cannot adapt? 188 00:09:40,190 --> 00:09:42,043 That's what we thought 189 00:09:42,175 --> 00:09:43,782 until we discovered 190 00:09:43,782 --> 00:09:46,242 what has been called an evolutionary scandal 191 00:09:46,242 --> 00:09:48,265 or an ancient sexual scandal: 192 00:09:48,265 --> 00:09:51,825 It's a microscopic world of animals, the bdelloid rotifers. 193 00:09:51,825 --> 00:09:57,106 These are females cloning themselves; never has any male been discovered. 194 00:09:57,106 --> 00:10:02,376 They exist since millions of years and we found them everywhere. 195 00:10:02,496 --> 00:10:05,060 And they are not only interesting 196 00:10:05,060 --> 00:10:08,804 because they can reproduce without males and evolve without males, 197 00:10:08,804 --> 00:10:10,855 we can also dry them out. 198 00:10:10,855 --> 00:10:11,903 I showed you: 199 00:10:11,903 --> 00:10:14,305 We can just take them, here in the park, 200 00:10:14,305 --> 00:10:19,002 a piece of lichen, a dry lichen, bring it back to the lab, 201 00:10:19,472 --> 00:10:20,738 and what you see - 202 00:10:20,738 --> 00:10:22,974 that's also what you see on the microscope - 203 00:10:23,044 --> 00:10:25,298 is this dry lichen and then they are introns. 204 00:10:25,398 --> 00:10:28,574 But when we add water, they start to live again. 205 00:10:28,574 --> 00:10:29,953 So these animals - 206 00:10:29,953 --> 00:10:33,614 We can dry them out at any stage in their life, 207 00:10:33,924 --> 00:10:35,635 and we can keep them dry. 208 00:10:35,635 --> 00:10:37,992 We can put them in the -80 freezer. 209 00:10:37,992 --> 00:10:40,775 We can send them to collaborators in the US, 210 00:10:40,775 --> 00:10:43,425 and if they add water, they live again. 211 00:10:44,315 --> 00:10:46,804 And it's not only one species. 212 00:10:46,804 --> 00:10:49,465 You could think, "Yeah, but it's just this rare animal." 213 00:10:49,465 --> 00:10:52,535 No, it's more than 400 species being described 214 00:10:53,076 --> 00:10:56,635 as having diversified into many morphological forms - 215 00:10:56,635 --> 00:11:00,276 all females reproducing without males, 216 00:11:00,476 --> 00:11:03,355 most of them being able to dry out. 217 00:11:03,355 --> 00:11:05,826 And of course this makes the newspaper: 218 00:11:05,826 --> 00:11:08,294 ["Asexual reproduction is possible."] 219 00:11:08,294 --> 00:11:10,196 Yes, it's possible. 220 00:11:11,166 --> 00:11:15,454 But then, of course, you might think, "How did these females evolve?" 221 00:11:15,454 --> 00:11:17,354 How do they create variability? - 222 00:11:17,354 --> 00:11:19,454 because we know it's essential for evolution. 223 00:11:19,454 --> 00:11:23,738 So, if they just cloned themselves, how do they ever evolve and adapt? 224 00:11:24,568 --> 00:11:25,664 And so, as a scientist, 225 00:11:25,664 --> 00:11:28,543 it is important to have these hypothesis to think of. 226 00:11:28,543 --> 00:11:29,885 So our hypothesis is - 227 00:11:29,885 --> 00:11:31,554 It's easy to work with this animal. 228 00:11:31,554 --> 00:11:35,143 You take a female in the wild, you start to clone it in the lab, 229 00:11:35,143 --> 00:11:37,824 you have millions of identical females, 230 00:11:37,824 --> 00:11:39,444 we dry them up, 231 00:11:40,694 --> 00:11:42,375 and then, our question was, 232 00:11:42,375 --> 00:11:44,384 "Do these females - 233 00:11:44,384 --> 00:11:47,504 What happens to the genetic material of these females 234 00:11:47,504 --> 00:11:48,776 when we dry them up?" 235 00:11:48,776 --> 00:11:50,435 We know from bacteria 236 00:11:50,435 --> 00:11:54,274 that drying up breaks their genetic material into pieces. 237 00:11:54,464 --> 00:11:57,140 Is this also happening in these animals? 238 00:11:57,570 --> 00:12:00,715 And then, what if they don't repair perfectly these pieces, 239 00:12:00,715 --> 00:12:03,294 is this a way to create variability? - 240 00:12:03,294 --> 00:12:04,287 meaning, 241 00:12:04,287 --> 00:12:09,157 if you replace males by drying up, you might also evolve. 242 00:12:09,447 --> 00:12:11,464 And so, that's what we tested. 243 00:12:11,584 --> 00:12:15,392 So Boris has designed a very nice protocol in the lab 244 00:12:15,392 --> 00:12:18,701 to dry them up with a high survival rate. 245 00:12:18,801 --> 00:12:22,101 And what happened to these females when they are dried up? 246 00:12:22,101 --> 00:12:25,703 You see, the longer they are dried up, the more their DNA is broken. 247 00:12:25,703 --> 00:12:28,853 The simpler the gel and the DNA migrates through it, 248 00:12:28,853 --> 00:12:30,672 the smaller the pieces. 249 00:12:31,122 --> 00:12:36,853 And when we hydrate them, what you see is that they start to repair. 250 00:12:36,853 --> 00:12:42,624 So they can come out of drying, they have their broken DNA - 251 00:12:42,624 --> 00:12:45,365 but they can survive with broken DNA apparently - 252 00:12:45,365 --> 00:12:47,415 and then they start to repair. 253 00:12:48,195 --> 00:12:49,314 And you know, 254 00:12:49,314 --> 00:12:50,686 if you have a cancer cell, 255 00:12:50,686 --> 00:12:55,304 it's known that sometimes during a division some DNA breaks, 256 00:12:55,304 --> 00:12:58,617 and it repairs this broken DNA but not perfectly, 257 00:12:58,635 --> 00:13:01,415 and you can have an aggressive cancer that appears. 258 00:13:01,415 --> 00:13:03,293 What they do in proton therapy is 259 00:13:03,293 --> 00:13:07,703 use proton radiation to completely destroy the DNA of cancer cells 260 00:13:07,703 --> 00:13:12,624 so the cells get completely broken DNA, and molecules too. 261 00:13:13,044 --> 00:13:16,834 So we thought if we do proton radiation to these animals, 262 00:13:16,834 --> 00:13:18,874 what happens? 263 00:13:18,874 --> 00:13:21,167 So we took, again, a female, 264 00:13:23,837 --> 00:13:25,857 we dry it up, 265 00:13:26,247 --> 00:13:28,287 we add proton radiation, 266 00:13:28,287 --> 00:13:29,512 and what happens? 267 00:13:29,512 --> 00:13:31,753 DNA gets completely broken. 268 00:13:31,753 --> 00:13:35,464 And this 800 grays of proton radiation are huge doses. 269 00:13:35,464 --> 00:13:38,233 There are no living cells that can survive this. 270 00:13:39,033 --> 00:13:40,376 But what's amazing here is - 271 00:13:40,376 --> 00:13:43,143 you really see the DNA is completely broken - 272 00:13:43,143 --> 00:13:48,985 when we re-hydrate these females, 99% of them survive. 273 00:13:49,135 --> 00:13:54,029 So they come out of drying with a completely broken DNA, 274 00:13:54,029 --> 00:13:55,594 without a problem, 275 00:13:55,594 --> 00:13:57,795 and then they start to repair. 276 00:13:57,985 --> 00:13:59,805 And of course, the question is, 277 00:13:59,805 --> 00:14:02,994 "Do they really repair perfectly? 278 00:14:02,994 --> 00:14:07,268 Or do they put all the pieces of DNA back together 279 00:14:07,268 --> 00:14:08,856 into their 12 chromosomes? - 280 00:14:08,856 --> 00:14:10,955 because we found they had 12 chromosomes - 281 00:14:10,955 --> 00:14:14,245 or is that just creating some variability?" 282 00:14:14,245 --> 00:14:18,375 So we have here preliminary results that I'm just showing you tonight, 283 00:14:18,575 --> 00:14:20,585 where we did this experiments, 284 00:14:20,585 --> 00:14:22,131 where we dry them up, 285 00:14:22,131 --> 00:14:24,061 we irradiate them, 286 00:14:24,061 --> 00:14:27,041 and then we look at its genomic structure. 287 00:14:27,041 --> 00:14:28,623 Not going too much into detail, 288 00:14:28,623 --> 00:14:30,644 but what you see here is, for example, 289 00:14:30,644 --> 00:14:34,006 pieces of the ridge of the genome from a female 290 00:14:34,006 --> 00:14:36,962 before she was radiated or dried up. 291 00:14:36,962 --> 00:14:39,445 Then we dry it up, we irradiate it, 292 00:14:39,445 --> 00:14:42,036 and we look at whether these pieces come back. 293 00:14:42,036 --> 00:14:45,794 You see here - everything is destroyed, and whether we get these pieces back - 294 00:14:45,794 --> 00:14:49,785 showing it's stitching back all these DNA pieces together 295 00:14:49,785 --> 00:14:51,565 into these 12 chromosomes. 296 00:14:51,565 --> 00:14:52,586 So they can do this: 297 00:14:52,586 --> 00:14:56,405 They reconstruct their genome as before, 298 00:14:56,405 --> 00:14:58,796 or at least, that's what it seems to look like. 299 00:14:58,796 --> 00:15:03,456 And even the descendants have that same structure 300 00:15:03,456 --> 00:15:05,621 as a parent’s alignment. 301 00:15:05,621 --> 00:15:08,725 So is there no genetic scrambling going on? 302 00:15:08,945 --> 00:15:10,136 That's possible. 303 00:15:10,136 --> 00:15:14,073 Maybe they don't, indeed, make a completely new genome; 304 00:15:14,073 --> 00:15:16,103 they keep their genome. 305 00:15:16,103 --> 00:15:18,763 But what we then ask ourselves is: 306 00:15:18,763 --> 00:15:22,933 "How can you survive when you are irradiated, 307 00:15:22,933 --> 00:15:27,973 because not only your DNA is broken, but also your molecules must be broken?" 308 00:15:27,973 --> 00:15:30,968 But they must keep their molecules somehow intact 309 00:15:30,968 --> 00:15:34,494 because you need these molecules to repair your DNA. 310 00:15:34,504 --> 00:15:35,693 So what do they have? 311 00:15:35,693 --> 00:15:37,374 What's their secret? 312 00:15:37,374 --> 00:15:40,125 What did we find by sequencing the first genome, 313 00:15:40,125 --> 00:15:43,953 really sequencing the entire alphabet of this animal? 314 00:15:43,953 --> 00:15:47,569 We found that they have a huge amount of antioxidants. 315 00:15:47,569 --> 00:15:50,235 Antioxidants are essential 316 00:15:50,325 --> 00:15:53,426 to protect yourself from these damaged cells. 317 00:15:53,426 --> 00:15:55,105 We all have antioxidants. 318 00:15:55,105 --> 00:15:57,356 That's because our cells accumulate damages, 319 00:15:57,356 --> 00:16:00,864 a kind of what we call oxidative stress, 320 00:16:00,864 --> 00:16:03,744 and your proteins, your DNA - everything gets damages. 321 00:16:03,744 --> 00:16:05,405 That's why we get older. 322 00:16:05,405 --> 00:16:09,245 And that's why you put all these creams on that are full of antioxidants, 323 00:16:09,245 --> 00:16:11,776 to try to prevent the aging of your cells, 324 00:16:11,776 --> 00:16:13,198 but it will not. 325 00:16:13,198 --> 00:16:17,793 But here, these animals have a huge amount of these antioxidants. 326 00:16:17,793 --> 00:16:19,672 So next time, think about it, 327 00:16:19,672 --> 00:16:23,162 don't buy all these expensive creams full of antioxidants, 328 00:16:23,162 --> 00:16:24,682 just drink some rotifers. 329 00:16:24,682 --> 00:16:27,432 You find them in the nature and they might help. 330 00:16:27,452 --> 00:16:28,552 (Laughter) 331 00:16:28,672 --> 00:16:30,073 But of course, 332 00:16:30,283 --> 00:16:31,968 these are all things we discovered, 333 00:16:31,968 --> 00:16:32,975 but as a scientist, 334 00:16:32,975 --> 00:16:36,511 when you discover things, you have even more questions. 335 00:16:36,691 --> 00:16:37,709 And so recently, 336 00:16:37,709 --> 00:16:40,330 I obtained a grant from the European Research Council 337 00:16:40,330 --> 00:16:44,498 to really try to demystify all these mysteries we found. 338 00:16:44,498 --> 00:16:47,107 We found they have this huge amount of antioxidants, 339 00:16:47,107 --> 00:16:49,278 but are they really effective? 340 00:16:49,288 --> 00:16:51,577 How do they repair this broken genome? 341 00:16:51,577 --> 00:16:53,767 What are the molecules, the mechanism they have 342 00:16:53,767 --> 00:16:58,478 to repair such a broken genome to survive drying, freezing? 343 00:16:58,608 --> 00:17:00,747 Then one last thing we discovered is 344 00:17:00,747 --> 00:17:05,480 by sequencing their genome, we found, among their genetic material, 345 00:17:05,480 --> 00:17:09,658 genetic material from bacteria, plants, fungi - 346 00:17:09,758 --> 00:17:13,848 so they seem to integrate DNA from their environment. 347 00:17:14,518 --> 00:17:16,496 And that's of course puzzling. 348 00:17:16,496 --> 00:17:17,509 But we also thought, 349 00:17:17,509 --> 00:17:19,899 If they can integrate this foreign DNA, 350 00:17:19,899 --> 00:17:23,587 can they also integrate DNA from other females out there, 351 00:17:23,587 --> 00:17:26,114 other rotifers that also dry up? 352 00:17:26,114 --> 00:17:27,845 And the first results we got on this 353 00:17:27,845 --> 00:17:33,230 is that we found some signatures of DNA exchange between these females, 354 00:17:33,230 --> 00:17:37,269 and we think it's not conventional sex, because we never found males, 355 00:17:37,269 --> 00:17:40,167 so they are not using the strategy that all animals do - 356 00:17:40,167 --> 00:17:43,416 a sperm and an ovocyte to exchange DNA. 357 00:17:43,596 --> 00:17:46,737 So what is the strategy? We have no idea. 358 00:17:46,737 --> 00:17:48,948 We call it sapphomixis - 359 00:17:48,948 --> 00:17:52,698 it's a mixing of genetic material between females. 360 00:17:52,978 --> 00:17:57,828 And you immediately see here why it's so beautiful to be a scientist - 361 00:17:57,828 --> 00:18:02,126 you discover a lot, but you have even more questions. 362 00:18:02,126 --> 00:18:03,316 But what's for sure 363 00:18:03,316 --> 00:18:07,742 is that we have a very interesting model organism here to understand, 364 00:18:07,742 --> 00:18:10,932 "How can they evolve without males? 365 00:18:11,632 --> 00:18:13,508 How does sapphomixis happen? 366 00:18:13,508 --> 00:18:16,378 And how can they survive such extreme conditions 367 00:18:16,378 --> 00:18:20,080 as drying up, freezing, and high doses of radiation?" 368 00:18:20,080 --> 00:18:22,588 There's so much still to discover there. 369 00:18:22,588 --> 00:18:26,387 And one of our next challenges is to send them to space. 370 00:18:26,477 --> 00:18:29,569 We got a grant from the European Space Agency 371 00:18:29,569 --> 00:18:34,759 to send, in 2019, rotifers to space, RISE. 372 00:18:34,799 --> 00:18:37,582 Why? Because space is also an extreme environment. 373 00:18:37,582 --> 00:18:39,320 We have no idea at the moment 374 00:18:39,320 --> 00:18:42,138 what this extreme environment has 375 00:18:42,138 --> 00:18:45,427 as pressure on astronauts or any living animal. 376 00:18:45,427 --> 00:18:48,387 This is a very interesting model organism to send out there 377 00:18:48,387 --> 00:18:52,216 and to understand much better what space is like. 378 00:18:52,296 --> 00:18:53,608 And of course, 379 00:18:53,608 --> 00:18:56,830 I cannot end this presentation without thanking all the funding 380 00:18:56,830 --> 00:19:00,938 but especially all the people in my lab - many are here. 381 00:19:01,628 --> 00:19:04,408 This work is never done by one person. 382 00:19:04,618 --> 00:19:07,529 A lab is really a group of persons working, 383 00:19:07,529 --> 00:19:08,811 tackling these questions. 384 00:19:08,811 --> 00:19:09,893 A lot of frustrations. 385 00:19:09,893 --> 00:19:12,233 They know it better than me right now. 386 00:19:12,663 --> 00:19:16,258 And then, I would like to thank the rotifer and Boris 387 00:19:16,258 --> 00:19:17,550 with the whole experiment 388 00:19:17,550 --> 00:19:20,070 because thanks to these rotifers, 389 00:19:20,070 --> 00:19:25,724 I'm really happy to go every day, or almost every day, to my work. 390 00:19:25,724 --> 00:19:29,199 At least, when I know I can do science and I can work with rotifers, 391 00:19:29,199 --> 00:19:30,958 I'm a happy person. 392 00:19:31,228 --> 00:19:32,549 Thank you. 393 00:19:32,549 --> 00:19:34,849 (Applause)