WEBVTT 00:00:11.277 --> 00:00:12.637 Good evening. 00:00:12.814 --> 00:00:16.512 Here you see a little petri dish that we use in the lab 00:00:16.512 --> 00:00:19.543 with a dry leaf, completely dry, 00:00:19.543 --> 00:00:21.805 and on there, there are females. 00:00:22.055 --> 00:00:24.007 Why do I say females? 00:00:24.007 --> 00:00:28.415 Because that's their way of life: They live and evolve without males; 00:00:28.415 --> 00:00:30.525 they got rid of males. 00:00:30.595 --> 00:00:32.476 And also, they are dry. 00:00:32.476 --> 00:00:35.586 They can dry up, and we can wait for years, 00:00:35.586 --> 00:00:38.505 put them in the freezer, and get them back. 00:00:38.505 --> 00:00:42.636 Tonight we will do a live experiment with one of my scientists, Boris, 00:00:42.636 --> 00:00:44.986 to resurrect these animals for you, 00:00:44.986 --> 00:00:46.497 these females. 00:00:48.357 --> 00:00:49.543 Thanks, Boris. 00:00:51.523 --> 00:00:53.395 So look around you. 00:00:53.745 --> 00:00:57.813 There is an amazing diversity of living organisms on this planet, 00:00:57.813 --> 00:01:02.001 from bacteria to fungi to plants to animals to human - 00:01:02.171 --> 00:01:04.213 nothing looks alike. 00:01:04.553 --> 00:01:11.192 But do you know that all this diversity arose once from a universal ancestor 00:01:11.192 --> 00:01:14.182 around 3.5 billion years ago? 00:01:14.182 --> 00:01:18.964 And this ancestor of all living organisms was a single simple cell, 00:01:18.964 --> 00:01:21.103 something like a bacterium. 00:01:21.453 --> 00:01:26.376 But how do we know that all life has evolved from a single cell? 00:01:27.030 --> 00:01:31.137 We know this because we all share the same alphabet; 00:01:31.137 --> 00:01:34.015 we have the same DNA code. 00:01:34.186 --> 00:01:37.507 DNA is a magical molecule of life. 00:01:37.604 --> 00:01:42.870 And DNA is only made up of four chemical building blocks: 00:01:43.683 --> 00:01:46.735 cytosine, guanine, adenine, thymine. 00:01:46.735 --> 00:01:51.465 So only four letters that make the whole alphabet of life. 00:01:52.167 --> 00:01:57.606 So yes, from bacteria to human, we only need four letters, 00:01:58.543 --> 00:02:03.462 but then, what's our DNA instruction book looking like? 00:02:03.853 --> 00:02:08.892 In each of our cells, we have around three billion of those letters, 00:02:08.892 --> 00:02:12.174 organized on 23 pairs of chromosomes. 00:02:12.233 --> 00:02:13.243 So you see here, 00:02:13.243 --> 00:02:15.583 it's a compaction of these four letters. 00:02:15.583 --> 00:02:20.903 But what makes you different from me is that these letters change. 00:02:21.182 --> 00:02:24.855 These letters change between all these individuals. 00:02:25.444 --> 00:02:30.527 So if we all have the same genetic code, it means we are all related. 00:02:30.616 --> 00:02:31.615 Yes, we are. 00:02:31.615 --> 00:02:34.018 We are all cousins from each other. 00:02:34.486 --> 00:02:36.196 But then, you may wonder: 00:02:36.196 --> 00:02:39.601 How did we evolve to so many complex forms 00:02:39.601 --> 00:02:43.006 from such a single cell a long time ago? 00:02:43.435 --> 00:02:48.096 And that's when I want you to remember the card game we have been playing. 00:02:48.266 --> 00:02:52.746 What's essential for evolution is genetic variation, 00:02:52.746 --> 00:02:55.123 its changes in these letters. 00:02:55.123 --> 00:02:58.565 So these letters change randomly. 00:02:58.895 --> 00:03:01.595 And most of these changes are neutral, 00:03:01.595 --> 00:03:05.323 they have no effect on the fitness of the individual, 00:03:05.323 --> 00:03:08.930 but if a change is an advantage, it can be selected. 00:03:08.930 --> 00:03:09.950 Remember? 00:03:09.950 --> 00:03:13.098 We select if a positive mutation appears. 00:03:13.098 --> 00:03:14.269 Why is it selected? 00:03:14.269 --> 00:03:16.761 Because the individual gets an advantage 00:03:16.761 --> 00:03:19.161 and it might reproduce more than the others 00:03:19.161 --> 00:03:21.459 so the mutation is transmitted. 00:03:22.141 --> 00:03:23.420 And we know 00:03:23.638 --> 00:03:26.039 that natural selection is cumulative, 00:03:26.039 --> 00:03:28.640 that we can accumulate this positive mutation, 00:03:28.640 --> 00:03:31.860 which is important for adaptation and evolution. 00:03:32.016 --> 00:03:34.232 So as I said, during the card game, 00:03:34.232 --> 00:03:38.602 there is nothing of intelligence or a creator out there 00:03:38.602 --> 00:03:40.373 for evolution. 00:03:40.996 --> 00:03:42.832 And look at cancer development. 00:03:42.842 --> 00:03:45.894 Cancer development is also an evolutionary process; 00:03:45.894 --> 00:03:48.206 it follows this same mechanism. 00:03:48.206 --> 00:03:53.752 Each of our cells accumulate randomly these changes, these mutations, 00:03:53.783 --> 00:03:58.203 but if one of these normal cells suddenly gets a growth advantage - 00:03:58.203 --> 00:04:01.861 a mutation that gives it a growth advantage compared to the other cells - 00:04:01.861 --> 00:04:04.690 it will start to grow quicker - 00:04:04.690 --> 00:04:06.519 an uncontrolled proliferation - 00:04:06.519 --> 00:04:08.621 and cancer can occur. 00:04:08.811 --> 00:04:10.669 And of course, it's a problem to human. 00:04:10.669 --> 00:04:12.010 We know it. 00:04:12.019 --> 00:04:14.720 But you know, animals also get cancer. 00:04:14.949 --> 00:04:17.321 But do all of them get cancer? 00:04:18.044 --> 00:04:22.201 There are a few mysterious species that don't develop cancer. 00:04:22.959 --> 00:04:24.119 What are they? 00:04:24.119 --> 00:04:27.230 The most notorious one is this naked mole rat. 00:04:27.269 --> 00:04:29.070 Very cute animal, no? 00:04:29.070 --> 00:04:30.071 (Laughter) 00:04:30.071 --> 00:04:32.794 For scientists, it's a very interesting animal. 00:04:32.794 --> 00:04:35.182 It's very small. It's like a mouse. 00:04:35.344 --> 00:04:39.314 But it lives for 30 years, and a mouse lives for four years. 00:04:39.364 --> 00:04:40.972 What's also interesting is 00:04:40.972 --> 00:04:43.708 if you inject the cancer cell in this animal, 00:04:43.708 --> 00:04:45.653 it will not develop. 00:04:45.793 --> 00:04:46.932 And why? 00:04:47.165 --> 00:04:49.177 Scientists have searched for this for years 00:04:49.177 --> 00:04:51.429 and found that they have this kind of molecule - 00:04:51.429 --> 00:04:53.813 a high molecular mass, hyaluronan; 00:04:53.813 --> 00:04:56.633 it's a kind of super sugar - 00:04:56.633 --> 00:04:59.903 that is secreted around the cells of these animals, 00:05:00.003 --> 00:05:02.924 and it makes their tissue very elastic. 00:05:02.924 --> 00:05:04.084 And why is it important? 00:05:04.084 --> 00:05:08.366 Because these animals dig into the soil, they make these burrows, 00:05:08.366 --> 00:05:10.658 and so their tissue needs to be very elastic. 00:05:10.658 --> 00:05:12.529 So it's an adaptation to this. 00:05:12.529 --> 00:05:14.109 But what's interesting 00:05:14.109 --> 00:05:17.659 is that this molecule, when it's secreted around the cell, 00:05:17.659 --> 00:05:21.319 prevents the cell from dividing or proliferating further. 00:05:21.599 --> 00:05:22.896 So you immediately see 00:05:22.896 --> 00:05:26.786 the interesting application of the discovery of such a molecule. 00:05:27.073 --> 00:05:30.134 But if you think this is the only interesting animal out there, 00:05:30.134 --> 00:05:31.375 you’re wrong. 00:05:31.435 --> 00:05:36.486 Nature is full of mysterious species, where we can discover so much. 00:05:36.666 --> 00:05:41.444 Nature has been an inspiration to scientists for so many years. 00:05:41.454 --> 00:05:43.523 Like Albert Einstein said, 00:05:43.563 --> 00:05:49.421 "We know less than one thousandth of 1% of what nature has to reveal to us." 00:05:49.461 --> 00:05:51.724 And if we start to destroy our nature, 00:05:51.724 --> 00:05:55.264 we will not even discover everything that's out there. 00:05:55.352 --> 00:05:56.942 Look at this gecko. 00:05:57.163 --> 00:06:02.638 This gecko, we know, can run quickly on vertical glass. 00:06:02.808 --> 00:06:03.819 But how? 00:06:03.819 --> 00:06:07.970 How can these animals adhere so strongly to glass 00:06:07.970 --> 00:06:09.910 and then just run on it? 00:06:09.920 --> 00:06:10.919 And so, for long, 00:06:10.919 --> 00:06:12.700 scientists looked at the molecule: 00:06:12.700 --> 00:06:16.813 What kind of molecule is secreted that makes them like a glue, 00:06:16.813 --> 00:06:18.790 like a strong adhesion? 00:06:18.950 --> 00:06:21.209 And in fact, by looking at these fingers, 00:06:21.209 --> 00:06:24.223 they found there's nothing of a molecule that is secreted, 00:06:24.223 --> 00:06:25.833 but it's a structure. 00:06:25.833 --> 00:06:27.384 What they discovered 00:06:27.384 --> 00:06:31.925 is that underneath these fingers, there are these hair-like structures, 00:06:31.925 --> 00:06:33.354 millions of them. 00:06:33.354 --> 00:06:36.134 And if you look even at the nanoscopic level, 00:06:36.134 --> 00:06:38.273 you see that at the end of all of these hairs, 00:06:38.273 --> 00:06:42.512 you have hundreds of these spatula-likes structures. 00:06:42.633 --> 00:06:45.013 And when these are in strong contact with glass, 00:06:45.013 --> 00:06:49.449 it creates a strong adhesion just through simple Van der Waals forces, 00:06:49.449 --> 00:06:52.672 the simple forces that make this strong adhesion. 00:06:52.672 --> 00:06:55.734 And when they rotate their fingers, 00:06:55.734 --> 00:07:00.270 this force releases immediately and they can run further. 00:07:00.270 --> 00:07:01.251 And of course, 00:07:01.271 --> 00:07:05.430 laboratories have now been interested to reconstruct these nano-structures 00:07:05.430 --> 00:07:08.130 to make strong adhesives. 00:07:08.590 --> 00:07:10.481 And that's what I want to show you: 00:07:10.481 --> 00:07:14.528 It's so interesting to study biology because there's so much to discover, 00:07:14.528 --> 00:07:17.060 because there has been such a long evolution 00:07:17.060 --> 00:07:21.659 of all kinds of specimens with all kinds of different adaptations. 00:07:22.179 --> 00:07:24.803 And what has puzzled me is reproduction. 00:07:24.803 --> 00:07:27.853 You know that for life, it's essential to reproduce; 00:07:28.183 --> 00:07:31.443 we need to reproduce or the species will go extinct. 00:07:31.443 --> 00:07:34.213 But do you know that sexual reproduction, 00:07:34.213 --> 00:07:35.873 the one we all know, 00:07:35.873 --> 00:07:38.764 is the queen of problems in evolutionary biology? 00:07:38.764 --> 00:07:41.304 For us scientists, it's really a puzzle. 00:07:41.643 --> 00:07:43.022 And why? 00:07:43.142 --> 00:07:47.104 Think about all the energy you need to spend to find a partner, 00:07:47.104 --> 00:07:49.864 all the strategies the male's developed 00:07:49.864 --> 00:07:53.654 to try to attract a female, to try to fertilize her, 00:07:54.074 --> 00:07:57.160 to the point that there is a battle of sexes. 00:07:57.160 --> 00:07:58.556 Believe me - 00:07:58.929 --> 00:08:02.740 a man penis is boring compared to this insect penis. 00:08:02.740 --> 00:08:05.010 This is a penis of a bean weevil, 00:08:05.010 --> 00:08:06.720 full of spines, 00:08:06.753 --> 00:08:11.891 and the males with the longest spines are those that fertilize most of the eggs. 00:08:12.102 --> 00:08:14.960 Of course, the female cannot reproduce anymore afterwards, 00:08:14.960 --> 00:08:18.770 but at least, the male is sure he has transmitted his genes. 00:08:19.170 --> 00:08:20.744 A look at this fruit fly. 00:08:20.744 --> 00:08:24.613 You might have many fruit flies in summer around your trash bin. 00:08:24.963 --> 00:08:27.618 This fruit fly, Drosophila bifurca, 00:08:27.618 --> 00:08:32.033 produces giant sperm, 20 times its body size. 00:08:32.033 --> 00:08:33.035 It's like, you men, 00:08:33.035 --> 00:08:36.753 you would have a sperm that is twenty times your body size, 00:08:36.753 --> 00:08:38.648 like a building of 12 stories. 00:08:38.648 --> 00:08:39.684 (Laughter) 00:08:39.684 --> 00:08:40.873 Wow! 00:08:41.134 --> 00:08:44.583 But at least, when it transmits this to the female, 00:08:44.703 --> 00:08:47.123 the receptacle of the female is filled, 00:08:47.123 --> 00:08:49.932 there is no space for another sperm, 00:08:49.932 --> 00:08:52.526 so it's sure to transmit its genes. 00:08:53.013 --> 00:08:56.876 But then, why did such a complicated mode of reproduction evolve? 00:08:56.876 --> 00:08:58.790 And why is it so omnipresent? 00:08:58.790 --> 00:09:01.021 Is it not just simpler to clone yourself? 00:09:01.021 --> 00:09:03.729 One individual makes a new individual? 00:09:04.221 --> 00:09:08.940 So why is sexual reproduction so prevalent in nature? 00:09:09.550 --> 00:09:11.690 In fact, for us biologists, 00:09:11.789 --> 00:09:17.049 sex is just about mixing genetic material of one individual with another individual 00:09:17.209 --> 00:09:21.719 to create each generation of offsprings that are all different. 00:09:21.809 --> 00:09:24.374 And that's a force of sexual reproduction: 00:09:24.374 --> 00:09:28.843 It creates every generation this genetic variability 00:09:28.843 --> 00:09:31.203 that is essential for evolution. 00:09:31.350 --> 00:09:35.112 So does it mean that animals that lose sexual reproduction 00:09:35.112 --> 00:09:37.682 or that abandon it or have no sexual reproduction 00:09:37.702 --> 00:09:40.113 cannot evolve, cannot adapt? 00:09:40.190 --> 00:09:42.043 That's what we thought 00:09:42.175 --> 00:09:43.782 until we discovered 00:09:43.782 --> 00:09:46.242 what has been called an evolutionary scandal 00:09:46.242 --> 00:09:48.265 or an ancient sexual scandal: 00:09:48.265 --> 00:09:51.825 It's a microscopic world of animals, the bdelloid rotifers. 00:09:51.825 --> 00:09:57.106 These are females cloning themselves; never has any male been discovered. 00:09:57.106 --> 00:10:02.376 They exist since millions of years and we found them everywhere. 00:10:02.496 --> 00:10:05.060 And they are not only interesting 00:10:05.060 --> 00:10:08.804 because they can reproduce without males and evolve without males, 00:10:08.804 --> 00:10:10.855 we can also dry them out. 00:10:10.855 --> 00:10:11.903 I showed you: 00:10:11.903 --> 00:10:14.305 We can just take them, here in the park, 00:10:14.305 --> 00:10:19.002 a piece of lichen, a dry lichen, bring it back to the lab, 00:10:19.472 --> 00:10:20.738 and what you see - 00:10:20.738 --> 00:10:22.974 that's also what you see on the microscope - 00:10:23.044 --> 00:10:25.298 is this dry lichen and then they are in trance. 00:10:25.398 --> 00:10:28.574 But when we add water, they start to live again. 00:10:28.574 --> 00:10:29.953 So these animals - 00:10:29.953 --> 00:10:33.614 We can dry them out at any stage in their life, 00:10:33.924 --> 00:10:35.635 and we can keep them dry. 00:10:35.635 --> 00:10:37.992 We can put them in the -80 freezer. 00:10:37.992 --> 00:10:40.775 We can send them to collaborators in the US, 00:10:40.775 --> 00:10:43.425 and if they add water, they live again. 00:10:44.315 --> 00:10:46.804 And it's not only one species. 00:10:46.804 --> 00:10:49.465 You could think, "Yeah, but it's just this rare animal." 00:10:49.465 --> 00:10:52.535 No, it's more than 400 species being described 00:10:53.076 --> 00:10:56.635 as having diversified into many morphological forms - 00:10:56.635 --> 00:11:00.276 all females reproducing without males, 00:11:00.476 --> 00:11:03.355 most of them being able to dry out. 00:11:03.355 --> 00:11:05.826 And of course this makes the newspaper: 00:11:05.826 --> 00:11:08.294 ["Asexual reproduction is possible."] 00:11:08.294 --> 00:11:10.196 Yes, it's possible. 00:11:11.166 --> 00:11:15.454 But then, of course, you might think, "How did these females evolve?" 00:11:15.454 --> 00:11:17.354 How do they create variability? - 00:11:17.354 --> 00:11:19.454 because we know it's essential for evolution. 00:11:19.454 --> 00:11:23.738 So, if they just cloned themselves, how do they ever evolve and adapt? 00:11:24.568 --> 00:11:25.664 And so, as a scientist, 00:11:25.664 --> 00:11:28.543 it is important to have these hypothesis to think of. 00:11:28.543 --> 00:11:29.885 So our hypothesis is - 00:11:29.885 --> 00:11:31.554 It's easy to work with this animal. 00:11:31.554 --> 00:11:35.143 You take a female in the wild, you start to clone it in the lab, 00:11:35.143 --> 00:11:37.824 you have millions of identical females, 00:11:37.824 --> 00:11:39.444 we dry them up, 00:11:40.694 --> 00:11:42.375 and then, our question was, 00:11:42.375 --> 00:11:44.384 "Do these females - 00:11:44.384 --> 00:11:47.504 What happens to the genetic material of these females 00:11:47.504 --> 00:11:48.776 when we dry them up?" 00:11:48.776 --> 00:11:50.435 We know from bacteria 00:11:50.435 --> 00:11:54.274 that drying up breaks their genetic material into pieces. 00:11:54.464 --> 00:11:57.140 Is this also happening in these animals? 00:11:57.570 --> 00:12:00.715 And then, what if they don't repair perfectly these pieces, 00:12:00.715 --> 00:12:03.294 is this a way to create variability? - 00:12:03.294 --> 00:12:04.287 meaning, 00:12:04.287 --> 00:12:09.157 if you replace males by drying up, you might also evolve. 00:12:09.447 --> 00:12:11.464 And so, that's what we tested. 00:12:11.584 --> 00:12:15.392 So Boris has designed a very nice protocol in the lab 00:12:15.392 --> 00:12:18.701 to dry them up with a high survival rate. 00:12:18.801 --> 00:12:22.101 And what happened to these females when they are dried up? 00:12:22.101 --> 00:12:25.703 You see, the longer they are dried up, the more their DNA is broken. 00:12:25.703 --> 00:12:28.853 The simpler the gel and the DNA migrates through it, 00:12:28.853 --> 00:12:30.672 the smaller the pieces. 00:12:31.122 --> 00:12:36.853 And when we hydrate them, what you see is that they start to repair. 00:12:36.853 --> 00:12:42.624 So they can come out of drying, they have their broken DNA - 00:12:42.624 --> 00:12:45.365 but they can survive with broken DNA apparently - 00:12:45.365 --> 00:12:47.415 and then they start to repair. 00:12:48.195 --> 00:12:49.314 And you know, 00:12:49.314 --> 00:12:50.686 if you have a cancer cell, 00:12:50.686 --> 00:12:55.304 it's known that sometimes during a division some DNA breaks, 00:12:55.304 --> 00:12:58.617 and it repairs this broken DNA but not perfectly, 00:12:58.635 --> 00:13:01.415 and you can have an aggressive cancer that appears. 00:13:01.415 --> 00:13:03.293 What they do in proton therapy is 00:13:03.293 --> 00:13:07.703 use proton radiation to completely destroy the DNA of cancer cells 00:13:07.703 --> 00:13:12.624 so the cells get completely broken DNA, and molecules too. 00:13:13.044 --> 00:13:16.834 So we thought if we do proton radiation to these animals, 00:13:16.834 --> 00:13:18.874 what happens? 00:13:18.874 --> 00:13:21.167 So we took, again, a female, 00:13:23.837 --> 00:13:25.857 we dry it up, 00:13:26.247 --> 00:13:28.287 we add proton radiation, 00:13:28.287 --> 00:13:29.512 and what happens? 00:13:29.512 --> 00:13:31.753 DNA gets completely broken. 00:13:31.753 --> 00:13:35.464 And this 800 grays of proton radiation are huge doses. 00:13:35.464 --> 00:13:38.233 There are no living cells that can survive this. 00:13:39.033 --> 00:13:40.376 But what's amazing here is - 00:13:40.376 --> 00:13:43.143 you really see the DNA is completely broken - 00:13:43.143 --> 00:13:48.985 when we re-hydrate these females, 99% of them survive. 00:13:49.135 --> 00:13:54.029 So they come out of drying with a completely broken DNA, 00:13:54.029 --> 00:13:55.594 without a problem, 00:13:55.594 --> 00:13:57.795 and then they start to repair. 00:13:57.985 --> 00:13:59.805 And of course, the question is, 00:13:59.805 --> 00:14:02.994 "Do they really repair perfectly? 00:14:02.994 --> 00:14:07.268 Or do they put all the pieces of DNA back together 00:14:07.268 --> 00:14:08.856 into their 12 chromosomes? - 00:14:08.856 --> 00:14:10.955 because we found they had 12 chromosomes - 00:14:10.955 --> 00:14:14.245 or is that just creating some variability?" 00:14:14.245 --> 00:14:18.375 So we have here preliminary results that I'm just showing you tonight, 00:14:18.575 --> 00:14:20.585 where we did this experiments, 00:14:20.585 --> 00:14:22.131 where we dry them up, 00:14:22.131 --> 00:14:24.061 we irradiate them, 00:14:24.061 --> 00:14:27.041 and then we look at its genomic structure. 00:14:27.041 --> 00:14:28.623 Not going too much into detail, 00:14:28.623 --> 00:14:30.644 but what you see here is, for example, 00:14:30.644 --> 00:14:34.006 pieces of the ridge of the genome from a female 00:14:34.006 --> 00:14:36.962 before she was radiated or dried up. 00:14:36.962 --> 00:14:39.445 Then we dry it up, we irradiate it, 00:14:39.445 --> 00:14:42.036 and we look at whether these pieces come back. 00:14:42.036 --> 00:14:45.794 You see here - everything is destroyed, and whether we get these pieces back - 00:14:45.794 --> 00:14:49.785 showing it's stitching back all these DNA pieces together 00:14:49.785 --> 00:14:51.565 into these 12 chromosomes. 00:14:51.565 --> 00:14:52.586 So they can do this: 00:14:52.586 --> 00:14:56.405 They reconstruct their genome as before, 00:14:56.405 --> 00:14:58.796 or at least, that's what it seems to look like. 00:14:58.796 --> 00:15:03.456 And even the descendants have that same structure 00:15:03.456 --> 00:15:05.621 as a parent’s alignment. 00:15:05.621 --> 00:15:08.725 So is there no genetic scrambling going on? 00:15:08.945 --> 00:15:10.136 That's possible. 00:15:10.136 --> 00:15:14.073 Maybe they don't, indeed, make a completely new genome; 00:15:14.073 --> 00:15:16.103 they keep their genome. 00:15:16.103 --> 00:15:18.763 But what we then ask ourselves is: 00:15:18.763 --> 00:15:22.933 "How can you survive when you are irradiated, 00:15:22.933 --> 00:15:27.973 because not only your DNA is broken, but also your molecules must be broken?" 00:15:27.973 --> 00:15:30.968 But they must keep their molecules somehow intact 00:15:30.968 --> 00:15:34.494 because you need these molecules to repair your DNA. 00:15:34.504 --> 00:15:35.693 So what do they have? 00:15:35.693 --> 00:15:37.374 What's their secret? 00:15:37.374 --> 00:15:40.125 What did we find by sequencing the first genome, 00:15:40.125 --> 00:15:43.953 really sequencing the entire alphabet of this animal? 00:15:43.953 --> 00:15:47.569 We found that they have a huge amount of antioxidants. 00:15:47.569 --> 00:15:50.235 Antioxidants are essential 00:15:50.325 --> 00:15:53.426 to protect yourself from these damaged cells. 00:15:53.426 --> 00:15:55.105 We all have antioxidants. 00:15:55.105 --> 00:15:57.356 That's because our cells accumulate damages, 00:15:57.356 --> 00:16:00.864 a kind of what we call oxidative stress, 00:16:00.864 --> 00:16:03.744 and your proteins, your DNA - everything gets damages. 00:16:03.744 --> 00:16:05.405 That's why we get older. 00:16:05.405 --> 00:16:09.245 And that's why you put all these creams on that are full of antioxidants, 00:16:09.245 --> 00:16:11.776 to try to prevent the aging of your cells, 00:16:11.776 --> 00:16:13.198 but it will not. 00:16:13.198 --> 00:16:17.793 But here, these animals have a huge amount of these antioxidants. 00:16:17.793 --> 00:16:19.672 So next time, think about it, 00:16:19.672 --> 00:16:23.162 don't buy all these expensive creams full of antioxidants, 00:16:23.162 --> 00:16:24.682 just drink some rotifers. 00:16:24.682 --> 00:16:27.432 You find them in the nature and they might help. 00:16:27.452 --> 00:16:28.552 (Laughter) 00:16:28.672 --> 00:16:30.073 But of course, 00:16:30.283 --> 00:16:31.968 these are all things we discovered, 00:16:31.968 --> 00:16:32.975 but as a scientist, 00:16:32.975 --> 00:16:36.511 when you discover things, you have even more questions. 00:16:36.691 --> 00:16:37.709 And so recently, 00:16:37.709 --> 00:16:40.330 I obtained a grant from the European Research Council 00:16:40.330 --> 00:16:44.498 to really try to demystify all these mysteries we found. 00:16:44.498 --> 00:16:47.107 We found they have this huge amount of antioxidants, 00:16:47.107 --> 00:16:49.278 but are they really effective? 00:16:49.288 --> 00:16:51.577 How do they repair this broken genome? 00:16:51.577 --> 00:16:53.767 What are the molecules, the mechanism they have 00:16:53.767 --> 00:16:58.478 to repair such a broken genome to survive drying, freezing? 00:16:58.608 --> 00:17:00.747 Then one last thing we discovered is 00:17:00.747 --> 00:17:05.480 by sequencing their genome, we found, among their genetic material, 00:17:05.480 --> 00:17:09.658 genetic material from bacteria, plants, fungi - 00:17:09.758 --> 00:17:13.848 so they seem to integrate DNA from their environment. 00:17:14.518 --> 00:17:16.496 And that's of course puzzling. 00:17:16.496 --> 00:17:17.509 But we also thought, 00:17:17.509 --> 00:17:19.899 If they can integrate this foreign DNA, 00:17:19.899 --> 00:17:23.587 can they also integrate DNA from other females out there, 00:17:23.587 --> 00:17:26.114 other rotifers that also dry up? 00:17:26.114 --> 00:17:27.845 And the first results we got on this 00:17:27.845 --> 00:17:33.230 is that we found some signatures of DNA exchange between these females, 00:17:33.230 --> 00:17:37.269 and we think it's not conventional sex, because we never found males, 00:17:37.269 --> 00:17:40.167 so they are not using the strategy that all animals do - 00:17:40.167 --> 00:17:43.416 a sperm and an ovocyte to exchange DNA. 00:17:43.596 --> 00:17:46.737 So what is the strategy? We have no idea. 00:17:46.737 --> 00:17:48.948 We call it sapphomixis - 00:17:48.948 --> 00:17:52.698 it's a mixing of genetic material between females. 00:17:52.978 --> 00:17:57.828 And you immediately see here why it's so beautiful to be a scientist - 00:17:57.828 --> 00:18:02.126 you discover a lot, but you have even more questions. 00:18:02.126 --> 00:18:03.316 But what's for sure 00:18:03.316 --> 00:18:07.742 is that we have a very interesting model organism here to understand, 00:18:07.742 --> 00:18:10.932 "How can they evolve without males? 00:18:11.632 --> 00:18:13.508 How does sapphomixis happen? 00:18:13.508 --> 00:18:16.378 And how can they survive such extreme conditions 00:18:16.378 --> 00:18:20.080 as drying up, freezing, and high doses of radiation?" 00:18:20.080 --> 00:18:22.588 There's so much still to discover there. 00:18:22.588 --> 00:18:26.387 And one of our next challenges is to send them to space. 00:18:26.477 --> 00:18:29.569 We got a grant from the European Space Agency 00:18:29.569 --> 00:18:34.759 to send, in 2019, rotifers to space, RISE. 00:18:34.799 --> 00:18:37.582 Why? Because space is also an extreme environment. 00:18:37.582 --> 00:18:39.320 We have no idea at the moment 00:18:39.320 --> 00:18:42.138 what this extreme environment has 00:18:42.138 --> 00:18:45.427 as pressure on astronauts or any living animal. 00:18:45.427 --> 00:18:48.387 This is a very interesting model organism to send out there 00:18:48.387 --> 00:18:52.216 and to understand much better what space is like. 00:18:52.296 --> 00:18:53.608 And of course, 00:18:53.608 --> 00:18:56.830 I cannot end this presentation without thanking all the funding 00:18:56.830 --> 00:19:00.938 but especially all the people in my lab - many are here. 00:19:01.628 --> 00:19:04.408 This work is never done by one person. 00:19:04.618 --> 00:19:07.529 A lab is really a group of persons working, 00:19:07.529 --> 00:19:08.811 tackling these questions. 00:19:08.811 --> 00:19:09.893 A lot of frustrations. 00:19:09.893 --> 00:19:12.233 They know it better than me right now. 00:19:12.663 --> 00:19:16.258 And then, I would like to thank the rotifer and Boris 00:19:16.258 --> 00:19:17.550 with the whole experiment 00:19:17.550 --> 00:19:20.070 because thanks to these rotifers, 00:19:20.070 --> 00:19:25.724 I'm really happy to go every day, or almost every day, to my work. 00:19:25.724 --> 00:19:29.199 At least, when I know I can do science and I can work with rotifers, 00:19:29.199 --> 00:19:30.958 I'm a happy person. 00:19:31.228 --> 00:19:32.549 Thank you. 00:19:32.549 --> 00:19:34.849 (Applause)