1 00:00:01,443 --> 00:00:03,750 (gentle music) 2 00:00:03,750 --> 00:00:05,390 Compared to our closest living 3 00:00:05,390 --> 00:00:07,750 genetic relatives, humans are, 4 00:00:07,750 --> 00:00:10,510 physically, at least, rather unimpressive. 5 00:00:10,510 --> 00:00:11,999 We lack strength. 6 00:00:11,999 --> 00:00:12,832 (chimp screeching) 7 00:00:12,832 --> 00:00:16,379 We can't run as fast and we are much worse at climbing. 8 00:00:16,379 --> 00:00:18,962 (upbeat music) 9 00:00:24,910 --> 00:00:29,010 Yet, we have architecture, religion, science, language 10 00:00:29,010 --> 00:00:32,493 literature, art, culture, and fission, 11 00:00:33,910 --> 00:00:37,770 achievements all made possible by our larger brain. 12 00:00:37,770 --> 00:00:40,110 And since the writings of Charles Darwin, 13 00:00:40,110 --> 00:00:41,490 we have believed this development 14 00:00:41,490 --> 00:00:43,393 to have been constant and linear. 15 00:00:45,061 --> 00:00:45,894 (speaks in foreign language) 16 00:00:45,894 --> 00:00:46,950 I always assumed that the advent 17 00:00:46,950 --> 00:00:48,503 of modern man was inevitable, 18 00:00:49,343 --> 00:00:50,790 that the development of homo habilis 19 00:00:50,790 --> 00:00:53,590 and homo erectus were destined to lead us to this point. 20 00:00:55,800 --> 00:00:58,100 (upbeat music) 21 00:00:58,100 --> 00:00:59,493 But is this really true? 22 00:01:00,400 --> 00:01:02,100 New findings from Dresden suggest 23 00:01:02,100 --> 00:01:04,030 a quite different conclusion, 24 00:01:04,030 --> 00:01:06,940 that the evolution of the human brain has been far less 25 00:01:06,940 --> 00:01:09,380 of a slow and gradual development 26 00:01:09,380 --> 00:01:12,480 and more the result of a banal coincidence, 27 00:01:12,480 --> 00:01:14,820 which can be traced back to the sudden change 28 00:01:14,820 --> 00:01:16,423 of a single gene. 29 00:01:20,082 --> 00:01:22,730 (speaks in a foreign language) 30 00:01:22,730 --> 00:01:24,210 If it turns out to be true that 31 00:01:24,210 --> 00:01:27,270 this point mutation is so causally significant, 32 00:01:27,270 --> 00:01:29,460 then you have to ask whether humans really were 33 00:01:29,460 --> 00:01:31,943 always destined to exist in their current form. 34 00:01:35,816 --> 00:01:38,399 (upbeat music) 35 00:01:40,655 --> 00:01:41,885 (speaks in a foreign language) 36 00:01:41,885 --> 00:01:43,280 If we summarize our various experiments 37 00:01:43,280 --> 00:01:45,410 and findings, it seems that we have made 38 00:01:45,410 --> 00:01:47,610 an important contribution to understanding 39 00:01:47,610 --> 00:01:50,153 how humans came to have such large brains. 40 00:01:51,860 --> 00:01:54,443 (upbeat music) 41 00:02:05,227 --> 00:02:08,010 (gentle music) 42 00:02:08,010 --> 00:02:12,080 Homo sapiens shares almost 99% of his genetic material 43 00:02:12,080 --> 00:02:13,263 with other hominids. 44 00:02:16,730 --> 00:02:19,080 Apart from a few genetic details, 45 00:02:19,080 --> 00:02:22,233 what sets us apart is the size of our brains. 46 00:02:27,338 --> 00:02:28,430 {\an8}(speaks in a foreign language) 47 00:02:28,430 --> 00:02:30,270 {\an8}If you think about human achievements, 48 00:02:30,270 --> 00:02:33,780 {\an8}not only individually, but also as part of a team, 49 00:02:33,780 --> 00:02:36,280 the moon landing 50 years ago is still something 50 00:02:36,280 --> 00:02:37,970 that blows my mind. 51 00:02:37,970 --> 00:02:39,903 Other hominids couldn't have done that. 52 00:02:40,819 --> 00:02:43,420 (upbeat music) 53 00:02:43,420 --> 00:02:46,740 Professor Dr. Wieland Huttner is head of a research group 54 00:02:46,740 --> 00:02:48,130 at the Max Planck Institute 55 00:02:48,130 --> 00:02:51,383 for Molecular Cell Biology and Genetics in Dresden. 56 00:02:52,910 --> 00:02:55,553 In 2001, he was appointed director. 57 00:02:59,470 --> 00:03:02,260 Even as a child, Wieland Huttner wanted to crack 58 00:03:02,260 --> 00:03:05,323 the many unsolved mysteries of the human brain. 59 00:03:10,329 --> 00:03:11,170 (speaks in foreign language) 60 00:03:11,170 --> 00:03:13,500 When I was 17, I got into an argument 61 00:03:13,500 --> 00:03:16,030 with a boy in my class about whether we would really 62 00:03:16,030 --> 00:03:17,803 ever understand the human brain. 63 00:03:18,645 --> 00:03:20,550 He said it would always be a mystery. 64 00:03:20,550 --> 00:03:21,750 I disagreed. 65 00:03:21,750 --> 00:03:24,420 So, I started thinking how I could best get involved 66 00:03:24,420 --> 00:03:25,873 with this area of research. 67 00:03:27,367 --> 00:03:30,030 I'd planned to study psychology or chemistry, 68 00:03:30,030 --> 00:03:31,650 thinking that either one of them would help me 69 00:03:31,650 --> 00:03:32,800 reach my goal. 70 00:03:32,800 --> 00:03:34,137 And then my father said, 71 00:03:34,137 --> 00:03:36,237 "Study medicine, that's right in between." 72 00:03:37,370 --> 00:03:38,950 So I studied medicine. 73 00:03:38,950 --> 00:03:41,300 But straight after the basic medical examination, 74 00:03:41,300 --> 00:03:42,873 I began to focus on the brain. 75 00:03:44,067 --> 00:03:47,560 (dramatic music) 76 00:03:47,560 --> 00:03:50,370 Since then, Wieland Huttner has been using his knowledge 77 00:03:50,370 --> 00:03:53,563 of medicine to answer precisely these questions. 78 00:03:55,240 --> 00:03:58,293 How did evolution cause the human brain to grow? 79 00:03:59,770 --> 00:04:03,283 What biological cell processes caused this to happen? 80 00:04:04,320 --> 00:04:06,230 Our brains are three times larger 81 00:04:06,230 --> 00:04:08,123 than those of other ape species. 82 00:04:09,330 --> 00:04:12,403 Which changes in our genome led to this growth? 83 00:04:13,708 --> 00:04:16,500 (speaks in foreign language) 84 00:04:16,500 --> 00:04:18,130 There are scientists who give up 85 00:04:18,130 --> 00:04:19,203 at a certain point. 86 00:04:20,268 --> 00:04:22,220 I don't believe that I am one of them. 87 00:04:22,220 --> 00:04:25,380 In the past 25 years, we have made a lot of progress 88 00:04:25,380 --> 00:04:27,930 and have managed to build on this progress as well. 89 00:04:29,120 --> 00:04:30,360 But that's only been possible due to 90 00:04:30,360 --> 00:04:33,043 the fantastic colleagues I have working alongside me. 91 00:04:35,442 --> 00:04:38,270 (dramatic music) 92 00:04:38,270 --> 00:04:41,157 13 scientists and assistants from around the world 93 00:04:41,157 --> 00:04:43,508 are working in Huttner's research group 94 00:04:43,508 --> 00:04:44,758 and partner laboratories. 95 00:04:47,885 --> 00:04:49,792 (speaks in foreign language) 96 00:04:49,792 --> 00:04:52,060 We are what you would call cell biologists. 97 00:04:52,060 --> 00:04:55,380 And so, as cell biologists, we began to address the question 98 00:04:55,380 --> 00:04:57,023 of how our brains grow. 99 00:04:58,400 --> 00:05:01,710 First, we studied what are known as the progenitor cells, 100 00:05:01,710 --> 00:05:04,623 which need to divide in order to produce nerve cells. 101 00:05:07,230 --> 00:05:09,410 And in the process, we noticed that they have 102 00:05:09,410 --> 00:05:11,403 an extremely interesting morphology. 103 00:05:13,430 --> 00:05:16,517 So we said, "Let's use this in order to isolate the cells." 104 00:05:18,463 --> 00:05:19,770 (dramatic music) 105 00:05:19,770 --> 00:05:22,100 The progenitor cells are the first step 106 00:05:22,100 --> 00:05:24,663 in the development of the embryonic brain. 107 00:05:25,780 --> 00:05:28,670 Managing to isolate these has formed the basis 108 00:05:28,670 --> 00:05:31,573 for studying the next stages in the growth process. 109 00:05:33,857 --> 00:05:34,690 (speaks in foreign language) 110 00:05:34,690 --> 00:05:35,930 For me, the most impressive example 111 00:05:35,930 --> 00:05:39,400 {\an8}of human brain capacity is Einstein's theory of relativity. 112 00:05:39,400 --> 00:05:42,870 {\an8}It's incredible how concepts as intangible as time, space, 113 00:05:42,870 --> 00:05:45,740 {\an8}and gravity can be combined in a single formula. 114 00:05:45,740 --> 00:05:47,940 And Einstein has thus far been proven right. 115 00:05:49,460 --> 00:05:52,300 (gentle music) 116 00:05:52,300 --> 00:05:56,120 Neurobiologist Dr. Michel Heide is a scientific assistant 117 00:05:56,120 --> 00:05:57,973 in Wieland Huttner's research group. 118 00:05:59,130 --> 00:06:01,300 For years, he has been involved in the search 119 00:06:01,300 --> 00:06:03,963 for the genetic triggers of human brain growth. 120 00:06:08,048 --> 00:06:09,950 (speaks in foreign language) 121 00:06:09,950 --> 00:06:12,360 The first question we asked ourselves was, 122 00:06:12,360 --> 00:06:14,930 which genes are actually active in these STEM cells 123 00:06:14,930 --> 00:06:16,793 or progenitor cells of the brain? 124 00:06:17,820 --> 00:06:20,823 So we came up with a list of around 3,000 genes. 125 00:06:21,940 --> 00:06:23,570 And what we found interesting, of course, 126 00:06:23,570 --> 00:06:25,170 is when they first appeared, 127 00:06:25,170 --> 00:06:27,320 or in what other mammals they can be found. 128 00:06:28,340 --> 00:06:30,700 We then managed to narrow it down to 50 genes 129 00:06:30,700 --> 00:06:32,770 that can only be found in primates. 130 00:06:32,770 --> 00:06:35,720 And off these 50, 15 were specific to humans 131 00:06:35,720 --> 00:06:37,420 and not found in any other mammal. 132 00:06:40,350 --> 00:06:42,943 And one of these 15 was ARHGAP11B. 133 00:06:45,272 --> 00:06:46,415 (gentle music) 134 00:06:46,415 --> 00:06:47,248 ARHGAP11B. 135 00:06:48,150 --> 00:06:51,110 {\an8}This gene, known as 11B for short, 136 00:06:51,110 --> 00:06:53,660 {\an8}attracted the scientists' attention. 137 00:06:53,660 --> 00:06:55,533 {\an8}It only occurs in humans. 138 00:06:57,580 --> 00:07:01,100 {\an8}Does this gene cause the progenitor cells to multiply? 139 00:07:01,100 --> 00:07:03,670 {\an8}These key cells are what cause the brain to grow 140 00:07:03,670 --> 00:07:05,203 in the embryonic phase. 141 00:07:10,990 --> 00:07:15,460 In 2015, the researchers began studying ARHGAP11B 142 00:07:15,460 --> 00:07:17,310 in more detail. 143 00:07:17,310 --> 00:07:19,550 They planted the human specific gene 144 00:07:19,550 --> 00:07:21,463 in the brain of a mouse embryo. 145 00:07:26,043 --> 00:07:26,876 (speaks in foreign language) 146 00:07:26,876 --> 00:07:27,960 In the original tests, 147 00:07:27,960 --> 00:07:31,410 we introduced the 11B gene into mouse embryos 148 00:07:31,410 --> 00:07:33,760 and encouraged its expression, as we say, 149 00:07:33,760 --> 00:07:37,060 for a transient period, just a few days. 150 00:07:37,060 --> 00:07:40,800 The mice's brains suddenly contained more progenitor cells. 151 00:07:40,800 --> 00:07:43,640 This is the prerequisite for more brain growth. 152 00:07:43,640 --> 00:07:45,330 And incredibly, in half the cases, 153 00:07:45,330 --> 00:07:47,610 the mice's brains were not only larger, 154 00:07:47,610 --> 00:07:50,030 they also showed extensive folds, 155 00:07:50,030 --> 00:07:52,080 which is otherwise never seen in rodents. 156 00:07:54,529 --> 00:07:57,200 (gentle music) 157 00:07:57,200 --> 00:08:00,003 The findings from Dresden were a game changer. 158 00:08:03,270 --> 00:08:05,090 AHRGAP11B triggered the development 159 00:08:05,090 --> 00:08:09,030 of significantly more basal brain STEM cells in the mice, 160 00:08:09,030 --> 00:08:11,070 and even cause folds in the otherwise 161 00:08:11,070 --> 00:08:13,600 smooth cerebral cortex to occur, 162 00:08:13,600 --> 00:08:16,433 in line with the pronounced folds we see in humans. 163 00:08:17,880 --> 00:08:20,763 The researchers decided to go one step further. 164 00:08:23,966 --> 00:08:26,460 (speaks in foreign language) 165 00:08:26,460 --> 00:08:27,660 There are other kinds of animals 166 00:08:27,660 --> 00:08:30,210 that are much better suited to brain analysis, 167 00:08:30,210 --> 00:08:31,160 such as the ferret. 168 00:08:32,090 --> 00:08:36,003 So we planted the 11B gene in this species' brains as well. 169 00:08:37,220 --> 00:08:38,900 And the interesting thing is that, 170 00:08:38,900 --> 00:08:41,870 while in the mice 11B caused certain stem cells 171 00:08:41,870 --> 00:08:43,470 to proliferate in the brain, 172 00:08:43,470 --> 00:08:45,693 {\an8}these were not exactly the right stem cells. 173 00:08:47,630 --> 00:08:48,770 {\an8}In the ferret, however, 174 00:08:48,770 --> 00:08:51,150 {\an8}exactly the right stem cells proliferated, 175 00:08:51,150 --> 00:08:52,883 {\an8}to six times their usual number. 176 00:08:54,815 --> 00:08:55,950 {\an8}(dramatic music) 177 00:08:55,950 --> 00:08:58,640 {\an8}Another sensational finding. 178 00:08:58,640 --> 00:09:02,170 {\an8}Even in ferrets, which already have a folded brain, 179 00:09:02,170 --> 00:09:05,423 gene 11B triggered a clear increase in brain size. 180 00:09:06,280 --> 00:09:09,803 The folds became stronger, and the cerebral cortex thicker. 181 00:09:12,840 --> 00:09:16,080 Could AHRGAP11B be the missing piece of the puzzle 182 00:09:16,080 --> 00:09:17,783 long sought by scientists, 183 00:09:18,780 --> 00:09:21,910 the key component in the growth of the human brain, 184 00:09:21,910 --> 00:09:25,143 and what led us to become the planet's dominant species? 185 00:09:31,498 --> 00:09:32,331 (speaks in foreign language) 186 00:09:32,331 --> 00:09:34,174 For me, our greatest achievement 187 00:09:34,174 --> 00:09:35,219 is mastering fire. 188 00:09:35,219 --> 00:09:36,310 (upbeat music) 189 00:09:36,310 --> 00:09:39,060 Dr. Franca Parianen is a neuroscientist, 190 00:09:39,060 --> 00:09:41,083 author, and keen science learner. 191 00:09:42,570 --> 00:09:45,310 She believes it better to have wrinkles in your brain 192 00:09:45,310 --> 00:09:46,360 than in your clothes. 193 00:09:53,770 --> 00:09:55,453 She knows a lot about both. 194 00:09:56,320 --> 00:09:58,923 She also knows about evolutionary brain growth. 195 00:10:03,901 --> 00:10:06,600 (speaks in foreign language) 196 00:10:06,600 --> 00:10:07,433 What has grown most clearly 197 00:10:07,433 --> 00:10:10,513 {\an8}over the course of human evolution is the neocortex. 198 00:10:11,560 --> 00:10:14,820 {\an8}Our entire brain has developed, but it's the neocortex 199 00:10:14,820 --> 00:10:17,220 in particular that has grown disproportionately. 200 00:10:18,280 --> 00:10:20,210 And it's this part of the brain that enables us 201 00:10:20,210 --> 00:10:21,410 to do many of the things 202 00:10:21,410 --> 00:10:23,600 that we associate with intelligence, 203 00:10:23,600 --> 00:10:25,650 like understanding cause and effect, 204 00:10:25,650 --> 00:10:27,300 predicting the future, and so on. 205 00:10:28,890 --> 00:10:30,670 When I'm solving math problems, 206 00:10:30,670 --> 00:10:33,020 ideally something in the front part of my brain 207 00:10:33,020 --> 00:10:33,873 should be active. 208 00:10:36,295 --> 00:10:38,020 {\an8}(dramatic music) 209 00:10:38,020 --> 00:10:41,783 {\an8}Complex thought processes, speaking, dreaming, 210 00:10:43,152 --> 00:10:45,200 {\an8}all of these things happen in the neocortex, 211 00:10:45,200 --> 00:10:46,793 {\an8}the youngest part of the brain. 212 00:10:48,460 --> 00:10:51,850 {\an8}The more furrows it has, the stronger the folding, 213 00:10:51,850 --> 00:10:54,623 {\an8}and the more room there is for the gray cells to grow. 214 00:10:55,660 --> 00:10:58,343 {\an8}But size does not equal intelligence. 215 00:11:04,614 --> 00:11:05,447 {\an8}(speaks in foreign language) 216 00:11:05,447 --> 00:11:06,640 If we looked at two different people 217 00:11:06,640 --> 00:11:08,647 and said, "This person has a larger brain 218 00:11:08,647 --> 00:11:10,650 "and that person has a smaller brain," 219 00:11:10,650 --> 00:11:12,400 we'd be talking about the weight. 220 00:11:12,400 --> 00:11:14,810 We can't deduce intelligence from weight. 221 00:11:14,810 --> 00:11:17,440 But if we looked at the interconnectedness within the brain, 222 00:11:17,440 --> 00:11:18,680 we'd be much better positioned 223 00:11:18,680 --> 00:11:21,430 to draw conclusions about intelligence. 224 00:11:21,430 --> 00:11:23,440 In other words, we can't just think in terms 225 00:11:23,440 --> 00:11:25,460 of building blocks, we have to ask, 226 00:11:25,460 --> 00:11:27,010 how does it all fit together? 227 00:11:27,010 --> 00:11:28,400 How does it work together? 228 00:11:28,400 --> 00:11:30,320 To what extent do these connections stretch 229 00:11:30,320 --> 00:11:31,700 over the entire cortex, 230 00:11:31,700 --> 00:11:33,770 and how quickly do the connections form? 231 00:11:33,770 --> 00:11:36,223 How quickly can one cell react to another? 232 00:11:37,380 --> 00:11:39,520 Another important point is memory. 233 00:11:39,520 --> 00:11:42,270 How large the memory is plays a very important role 234 00:11:42,270 --> 00:11:44,020 when discussing human intelligence. 235 00:11:46,431 --> 00:11:47,360 (gentle music) 236 00:11:47,360 --> 00:11:50,400 The researchers at the Max Planck Institute in Dresden 237 00:11:50,400 --> 00:11:54,130 have found a human gene that causes nerve cells to multiply 238 00:11:54,130 --> 00:11:56,360 and the cerebral cortex to grow, 239 00:11:56,360 --> 00:11:58,263 at least in mice and ferrets. 240 00:11:59,380 --> 00:12:01,010 But does it have the same effect 241 00:12:01,010 --> 00:12:03,353 in more highly developed life forms? 242 00:12:05,399 --> 00:12:07,344 (speaks in foreign language) 243 00:12:07,344 --> 00:12:09,410 We found that AHRGAP11B multiplied 244 00:12:09,410 --> 00:12:11,810 the progenitor cells of the mice's brains 245 00:12:11,810 --> 00:12:13,640 and also caused the brains to grow, 246 00:12:13,640 --> 00:12:15,723 sometimes even with pronounced folds. 247 00:12:17,920 --> 00:12:19,370 We have to acknowledge that mice 248 00:12:19,370 --> 00:12:21,360 and humans are quite far apart, 249 00:12:21,360 --> 00:12:23,910 especially in terms of brain structure. 250 00:12:23,910 --> 00:12:27,570 That's why we decided that if AHRGAP11B really is 251 00:12:27,570 --> 00:12:29,810 the crucial gene in terms of the evolution 252 00:12:29,810 --> 00:12:31,660 and development of the human brain, 253 00:12:31,660 --> 00:12:34,243 we need a test subject that is closer to humans. 254 00:12:36,610 --> 00:12:37,700 (gentle music) 255 00:12:37,700 --> 00:12:39,570 Michelle Heide was therefore assigned 256 00:12:39,570 --> 00:12:42,910 with introducing the human gene AHRGAP11B 257 00:12:42,910 --> 00:12:46,633 into the embryonic brain of a primate for the first time. 258 00:12:50,423 --> 00:12:51,630 (speaks in foreign language) 259 00:12:51,630 --> 00:12:52,830 We decided to carry out 260 00:12:52,830 --> 00:12:55,323 the first experiments on common marmosets. 261 00:12:56,670 --> 00:12:58,410 These are relatively small monkeys 262 00:12:58,410 --> 00:13:01,210 that have a smooth brain in contrast to humans 263 00:13:01,210 --> 00:13:03,683 and chimpanzees and other higher primates. 264 00:13:05,290 --> 00:13:06,910 However, these animals already have 265 00:13:06,910 --> 00:13:10,500 all the stem cell populations that we also find in humans, 266 00:13:10,500 --> 00:13:13,715 that makes them the ideal candidate for these tests. 267 00:13:13,715 --> 00:13:16,450 (gentle music) 268 00:13:16,450 --> 00:13:19,320 Experiments on unborn animals carried out 269 00:13:19,320 --> 00:13:22,740 under strict international ethical guidelines are essential 270 00:13:22,740 --> 00:13:25,733 for the basic research work of the Dresden scientists. 271 00:13:30,372 --> 00:13:33,750 (speaks in foreign language) 272 00:13:33,750 --> 00:13:35,720 Our questions about why the human brain 273 00:13:35,720 --> 00:13:38,270 has become larger during the course of evolution 274 00:13:38,270 --> 00:13:41,120 and also during the development of the fetus, 275 00:13:41,120 --> 00:13:43,250 and how this is connected to what are known as 276 00:13:43,250 --> 00:13:46,210 the stem cells that produce these cells in the brain, 277 00:13:46,210 --> 00:13:48,240 can only be answered by carrying out research 278 00:13:48,240 --> 00:13:49,970 on living animals. 279 00:13:49,970 --> 00:13:51,770 That's not possible in a Petri dish. 280 00:13:54,664 --> 00:13:56,730 And our research also has a medical aspect, 281 00:13:56,730 --> 00:13:59,850 especially in the fight against neurodegenerative diseases, 282 00:13:59,850 --> 00:14:01,650 which are currently on the increase. 283 00:14:03,100 --> 00:14:04,990 If you're considering the cell replacement, 284 00:14:04,990 --> 00:14:07,640 you need to know about stem and progenitor cells, 285 00:14:07,640 --> 00:14:09,453 which we have now studied in detail. 286 00:14:10,490 --> 00:14:12,490 And these studies can't be done on mice. 287 00:14:14,151 --> 00:14:16,670 The mouse has hardly any of the stem and progenitor cells 288 00:14:16,670 --> 00:14:18,093 that shape our human brain. 289 00:14:22,960 --> 00:14:26,210 We have no alternative but to study the non-human primates 290 00:14:26,210 --> 00:14:27,700 that are our closest relatives, 291 00:14:27,700 --> 00:14:29,973 the ones we're allowed to experiment on. 292 00:14:32,767 --> 00:14:35,910 (gentle music) 293 00:14:35,910 --> 00:14:37,840 In a Japanese partner laboratory 294 00:14:37,840 --> 00:14:40,580 specializing in such experiments, 295 00:14:40,580 --> 00:14:44,143 AHRGAP11B is introduced into the monkeys egg cells. 296 00:14:46,252 --> 00:14:48,410 (speaks in foreign language) 297 00:14:48,410 --> 00:14:50,550 The procedure involves taking the egg cells 298 00:14:50,550 --> 00:14:53,970 from the monkeys and then fertilizing them in vitro, 299 00:14:53,970 --> 00:14:56,563 in much the same way as we do with human egg cells. 300 00:14:57,470 --> 00:14:59,010 Then we inject them with a virus 301 00:14:59,010 --> 00:15:01,453 that is carrying the AHRGAP11B gene. 302 00:15:02,764 --> 00:15:04,970 The virus then infects the fertilized egg cells 303 00:15:04,970 --> 00:15:07,340 and integrates itself into the genetic material 304 00:15:07,340 --> 00:15:08,957 of the marmoset. 305 00:15:08,957 --> 00:15:11,050 And these egg cells are then transferred back 306 00:15:11,050 --> 00:15:11,913 into the animal. 307 00:15:12,890 --> 00:15:16,450 We stop the process on day 101 or 102, 308 00:15:16,450 --> 00:15:18,260 in the second trimester, 309 00:15:18,260 --> 00:15:20,200 meaning the animals are not born. 310 00:15:20,200 --> 00:15:22,500 We terminate them in the fetal stage. 311 00:15:22,500 --> 00:15:24,293 This was very important for us. 312 00:15:26,389 --> 00:15:28,230 (gentle music) 313 00:15:28,230 --> 00:15:29,780 It takes several months before 314 00:15:29,780 --> 00:15:32,200 the first genetically altered monkey brains 315 00:15:32,200 --> 00:15:33,100 arrive from Japan. 316 00:15:38,286 --> 00:15:40,160 (speaks in foreign language) 317 00:15:40,160 --> 00:15:41,630 Of course, we were sent pictures 318 00:15:41,630 --> 00:15:43,650 of the first brains after they were taken out 319 00:15:43,650 --> 00:15:44,603 of the monkeys. 320 00:15:45,470 --> 00:15:47,180 After that, it took a very long time 321 00:15:47,180 --> 00:15:48,680 to get all the approvals we needed 322 00:15:48,680 --> 00:15:50,623 to import the brains into Germany. 323 00:15:52,331 --> 00:15:55,431 (dramatic music) 324 00:15:55,431 --> 00:15:56,900 (speaks in foreign language) 325 00:15:56,900 --> 00:15:59,060 First we check if the specimens were kept cool 326 00:15:59,060 --> 00:16:00,580 during transport. 327 00:16:00,580 --> 00:16:02,110 If the cooling was ineffective, 328 00:16:02,110 --> 00:16:05,230 than the RNA molecules can break down, for example. 329 00:16:05,230 --> 00:16:08,130 That prevents us from being able to detect certain things. 330 00:16:10,510 --> 00:16:13,423 Then we measure the standard parameters, such as the size. 331 00:16:17,740 --> 00:16:20,570 And then the specimen goes for analysis. 332 00:16:20,570 --> 00:16:22,990 We usually separate the two halves of the brain, 333 00:16:22,990 --> 00:16:24,330 because that enables us to do 334 00:16:24,330 --> 00:16:25,880 two different things with them. 335 00:16:28,900 --> 00:16:30,893 What will these experiments reveal? 336 00:16:32,930 --> 00:16:36,670 First, the brains of the monkey fetuses are encased in a gel 337 00:16:36,670 --> 00:16:38,620 which allows the researchers to cut them 338 00:16:38,620 --> 00:16:42,663 into wafer thin slices of just 90 micrometers in width. 339 00:16:47,394 --> 00:16:48,227 (speaks in foreign language) 340 00:16:48,227 --> 00:16:50,290 We're mainly interested in the stem cells. 341 00:16:50,290 --> 00:16:52,210 If I were looking at the brain as a whole, 342 00:16:52,210 --> 00:16:54,590 I wouldn't be able to see these stem cells. 343 00:16:54,590 --> 00:16:56,690 The stem cells are found inside the brain. 344 00:16:57,561 --> 00:17:00,311 (dramatic music) 345 00:17:04,201 --> 00:17:08,230 That was perfect slicing, textbook stuff. 346 00:17:08,230 --> 00:17:10,840 Michel Heide will analyze around a thousand 347 00:17:10,840 --> 00:17:13,923 of these brain tissue samples over the next few months. 348 00:17:18,326 --> 00:17:19,787 (speaks in foreign language) 349 00:17:19,787 --> 00:17:22,390 So in the next step, we want to color these stem cells. 350 00:17:22,390 --> 00:17:24,390 There are different populations of stem cells, 351 00:17:24,390 --> 00:17:26,230 and if we looked at the section as it is, 352 00:17:26,230 --> 00:17:28,040 we would just see groups of cells 353 00:17:28,040 --> 00:17:30,140 that we can't distinguish from each other. 354 00:17:31,512 --> 00:17:33,563 (gentle music) 355 00:17:33,563 --> 00:17:35,120 Making stem cells visible to the human eye 356 00:17:35,120 --> 00:17:37,500 is a complex process, 357 00:17:37,500 --> 00:17:39,630 one that the scientists here have optimized 358 00:17:39,630 --> 00:17:40,580 for their research. 359 00:17:44,007 --> 00:17:45,060 (speaks in foreign language) 360 00:17:45,060 --> 00:17:47,423 We use different markers for these neurons. 361 00:17:48,380 --> 00:17:50,300 We can die the neurons that are found 362 00:17:50,300 --> 00:17:52,850 deep inside the brain that are somewhat older 363 00:17:52,850 --> 00:17:54,990 from an evolutionary perspective, 364 00:17:54,990 --> 00:17:57,090 as well as neurons that are found higher up, 365 00:17:57,090 --> 00:17:58,390 and are therefore younger. 366 00:17:59,250 --> 00:18:00,977 What's interesting for us is not only 367 00:18:00,977 --> 00:18:02,710 the number of stem cells, 368 00:18:02,710 --> 00:18:05,430 but also the number of different neurons. 369 00:18:05,430 --> 00:18:08,620 The question is whether AHRGAP11B causes the stem cells 370 00:18:08,620 --> 00:18:10,590 to multiply, and therefore to increase 371 00:18:10,590 --> 00:18:11,690 the number of neurons. 372 00:18:13,908 --> 00:18:14,985 (dramatic music) 373 00:18:14,985 --> 00:18:16,980 The moment of truth has arrived. 374 00:18:16,980 --> 00:18:20,440 The results of years of research is finally here, 375 00:18:20,440 --> 00:18:21,460 and proves in detail 376 00:18:22,308 --> 00:18:24,920 what the researchers had only suspected. 377 00:18:24,920 --> 00:18:26,783 It's a scientific breakthrough. 378 00:18:27,866 --> 00:18:28,699 (speaks in foreign Language) 379 00:18:28,699 --> 00:18:29,899 And the folds? 380 00:18:29,899 --> 00:18:30,732 (speaks in foreign language) 381 00:18:30,732 --> 00:18:31,565 Yes, you can see it here. 382 00:18:31,565 --> 00:18:34,800 It starts at the front and then becomes more parietal. 383 00:18:34,800 --> 00:18:37,080 And what becomes clearer here are the folds, 384 00:18:37,080 --> 00:18:40,110 not so thick at first, but then getting thicker. 385 00:18:40,110 --> 00:18:42,823 And here I started to measure the GI. 386 00:18:42,823 --> 00:18:43,656 (speaks in foreign language) 387 00:18:43,656 --> 00:18:44,790 And usually at this stage of growth, 388 00:18:44,790 --> 00:18:45,970 there wouldn't be any folds. 389 00:18:45,970 --> 00:18:46,803 (speaks in foreign language) 390 00:18:46,803 --> 00:18:47,900 It would be completely smooth. 391 00:18:47,900 --> 00:18:48,733 (speaks in foreign language) 392 00:18:48,733 --> 00:18:49,566 Great. 393 00:18:49,566 --> 00:18:51,154 And that's just in one, or in several of them? 394 00:18:51,154 --> 00:18:51,987 (speaks in foreign language) 395 00:18:51,987 --> 00:18:53,110 That's just from one as an example, 396 00:18:53,110 --> 00:18:55,169 but you can see the same pattern in all the others. 397 00:18:55,169 --> 00:18:56,002 (speaks in foreign language) 398 00:18:56,002 --> 00:18:56,835 In all of them? 399 00:18:56,835 --> 00:18:57,668 (speaks in foreign language) 400 00:18:57,668 --> 00:18:58,757 To different degrees, of course, 401 00:18:58,757 --> 00:18:59,590 but it's always visible. 402 00:19:02,125 --> 00:19:04,590 The the results from the marmoset brains are impressive 403 00:19:04,590 --> 00:19:06,090 because they show these folds, 404 00:19:06,090 --> 00:19:08,840 even though the brains are normally completely smooth. 405 00:19:08,840 --> 00:19:11,140 And we can also see that the brains are much larger 406 00:19:11,140 --> 00:19:12,530 than they would usually be. 407 00:19:12,530 --> 00:19:13,610 We can see that the relevant 408 00:19:13,610 --> 00:19:15,560 stem cell populations have grown, 409 00:19:15,560 --> 00:19:18,310 so we can observe all the things we were hoping to see. 410 00:19:19,699 --> 00:19:22,440 {\an8}(gentle music) 411 00:19:22,440 --> 00:19:25,710 {\an8}The AHRGAP11B gene has reproduced exactly 412 00:19:25,710 --> 00:19:27,810 the same nerve cells that are also present 413 00:19:27,810 --> 00:19:29,543 in large numbers in humans. 414 00:19:31,250 --> 00:19:34,870 11B has therefore caused the brains to grow in mouse, 415 00:19:34,870 --> 00:19:37,053 ferret, and marmoset embryos. 416 00:19:38,957 --> 00:19:40,810 (speaks in foreign language) 417 00:19:40,810 --> 00:19:42,280 When you look at these pictures, 418 00:19:42,280 --> 00:19:44,030 they almost look like works of art. 419 00:19:44,940 --> 00:19:48,100 The various colors merge into the different layers, 420 00:19:48,100 --> 00:19:50,003 {\an8}making for very impressive images. 421 00:19:52,309 --> 00:19:53,460 (dramatic music) 422 00:19:53,460 --> 00:19:57,270 Planning, taking action, understanding numbers, 423 00:19:57,270 --> 00:20:00,250 awareness of our environment and fellow humans, 424 00:20:00,250 --> 00:20:01,363 self-awareness. 425 00:20:02,240 --> 00:20:04,300 Is our large brain the sole reason 426 00:20:04,300 --> 00:20:07,420 for these exclusively human abilities? 427 00:20:07,420 --> 00:20:10,573 Where exactly is the dividing line between man and ape? 428 00:20:11,564 --> 00:20:13,982 (chess piece clattering) 429 00:20:13,982 --> 00:20:16,200 (birds chirping) 430 00:20:16,200 --> 00:20:19,070 Since 2001, Leipzig Zoo has been home 431 00:20:19,070 --> 00:20:22,120 to the Wolfgang Kohler Primate Research Center, 432 00:20:22,120 --> 00:20:23,903 also known as Pongoland. 433 00:20:24,840 --> 00:20:27,053 Four species of great ape live here. 434 00:20:28,080 --> 00:20:29,570 The center provides the scientists 435 00:20:29,570 --> 00:20:32,940 of the Max Planck Institute for Evolutionary Anthropology 436 00:20:32,940 --> 00:20:34,610 closer insights into the behavior 437 00:20:34,610 --> 00:20:36,803 and cognitive abilities of hominids. 438 00:20:40,144 --> 00:20:42,180 (speaks in foreign language) 439 00:20:42,180 --> 00:20:43,613 I think that one of 440 00:20:43,613 --> 00:20:46,040 {\an8}the most important achievements of humans is education, 441 00:20:46,040 --> 00:20:47,354 {\an8}meaning that we're capable of passing knowledge on 442 00:20:47,354 --> 00:20:51,320 {\an8}to others, and not just from one person to another, 443 00:20:51,320 --> 00:20:53,280 like from a parent to a child, 444 00:20:53,280 --> 00:20:56,050 but also by passing knowledge down from one generation 445 00:20:56,050 --> 00:20:58,600 to the next, in a collective and systematic manner. 446 00:20:59,880 --> 00:21:02,312 (gentle music) 447 00:21:02,312 --> 00:21:03,830 Dr. Katja Liebal is a professor 448 00:21:03,830 --> 00:21:06,343 of comparative developmental psychology. 449 00:21:08,410 --> 00:21:10,610 For years, she has been studying differences 450 00:21:10,610 --> 00:21:12,833 in the ways humans and apes communicate. 451 00:21:14,697 --> 00:21:17,483 (orangutan grunting) 452 00:21:17,483 --> 00:21:18,660 (speaks in foreign language) 453 00:21:18,660 --> 00:21:19,720 What we've just heard is 454 00:21:19,720 --> 00:21:22,010 what's known as a long call. 455 00:21:22,010 --> 00:21:24,900 It's a territorial call, which the primates also use 456 00:21:24,900 --> 00:21:27,990 in the wild to indicate that the dominant male is claiming 457 00:21:27,990 --> 00:21:29,393 a piece of land as his own. 458 00:21:30,376 --> 00:21:32,040 And he sometimes does this to zoo visitors 459 00:21:32,040 --> 00:21:35,120 whom he knows well, or is willing to tolerate. 460 00:21:35,120 --> 00:21:37,190 He sometimes throws a few things around, 461 00:21:37,190 --> 00:21:39,750 unfortunately not in any particular direction. 462 00:21:39,750 --> 00:21:42,020 At that point, it's important to take a step back 463 00:21:42,020 --> 00:21:43,900 and not provoke him any further. 464 00:21:46,929 --> 00:21:50,020 Katja Lema carried out a large part of her PhD research 465 00:21:50,020 --> 00:21:53,410 in Pongoland, also studying orangutans. 466 00:21:53,410 --> 00:21:56,773 One of them was Bimbo, who can clearly still remember her. 467 00:21:57,816 --> 00:22:00,010 (speaks in foreign language) 468 00:22:00,010 --> 00:22:01,610 I actually performed, as an experiment, 469 00:22:01,610 --> 00:22:04,580 to find out where the great apes come to each other's aid, 470 00:22:04,580 --> 00:22:06,330 especially when they see something happening 471 00:22:06,330 --> 00:22:09,703 to a fellow animal, such as being bothered by a human. 472 00:22:10,625 --> 00:22:12,840 And the question was, how do you annoy apes 473 00:22:12,840 --> 00:22:14,430 without crossing ethical boundaries 474 00:22:14,430 --> 00:22:16,620 and irritating them too much? 475 00:22:16,620 --> 00:22:18,360 So what we did is offer them food 476 00:22:18,360 --> 00:22:20,653 and then pulled it away and ate it ourselves. 477 00:22:24,058 --> 00:22:25,930 And that was enough to ensure that, even after 10 years, 478 00:22:25,930 --> 00:22:27,780 he still can't stand the sight of me. 479 00:22:30,733 --> 00:22:31,566 (upbeat music) 480 00:22:31,566 --> 00:22:32,780 Bimbo's anger is clear to us 481 00:22:32,780 --> 00:22:35,053 from his gestures and facial expressions. 482 00:22:35,920 --> 00:22:38,423 But not everything can be translated directly. 483 00:22:43,179 --> 00:22:44,012 (speaks in foreign language) 484 00:22:44,012 --> 00:22:46,330 What we know is that the eyes, for example, 485 00:22:46,330 --> 00:22:48,000 are not as strong a communicative signal 486 00:22:48,000 --> 00:22:49,720 as they are in humans. 487 00:22:49,720 --> 00:22:52,340 That's because the white sclera is missing. 488 00:22:52,340 --> 00:22:54,000 They don't seem to use their eyes as much 489 00:22:54,000 --> 00:22:56,480 to determine where someone is looking. 490 00:22:56,480 --> 00:22:58,770 You can often see that, in interactions, 491 00:22:58,770 --> 00:23:01,990 the orangutans themselves avoid direct eye contact. 492 00:23:01,990 --> 00:23:04,510 In gorillas, that's also a strong signal. 493 00:23:04,510 --> 00:23:06,220 It can even be understood as a threat 494 00:23:06,220 --> 00:23:07,920 when a person stares at a gorilla. 495 00:23:09,631 --> 00:23:12,214 (gentle music) 496 00:23:17,800 --> 00:23:21,283 Unlike monkeys, humans communicate a lot with their eyes. 497 00:23:22,270 --> 00:23:25,250 The dark circle of the pupil against the white background 498 00:23:25,250 --> 00:23:29,020 enabled early humans to convey information wordlessly, 499 00:23:29,020 --> 00:23:32,003 presumably long before spoken language developed. 500 00:23:35,890 --> 00:23:39,290 Then came hand gestures and facial expressions, 501 00:23:39,290 --> 00:23:41,973 important tools for communicating within a group. 502 00:23:49,379 --> 00:23:51,360 (speaks in foreign language) 503 00:23:51,360 --> 00:23:54,247 Monkeys don't use abstracts gestures like, 504 00:23:54,247 --> 00:23:57,007 "It's okay," or, "I'm going for a cigarette." 505 00:23:58,240 --> 00:24:00,010 Nor do they make symbolic gestures 506 00:24:00,010 --> 00:24:02,223 that imitate movements or shapes. 507 00:24:08,590 --> 00:24:10,900 Typical chimpanzee gestures would include 508 00:24:10,900 --> 00:24:13,750 stretching out the arm to offer food. 509 00:24:13,750 --> 00:24:15,600 They also do it sometimes to beg, 510 00:24:15,600 --> 00:24:17,163 when another animal has food. 511 00:24:19,290 --> 00:24:21,360 It is still often unclear what is meant 512 00:24:21,360 --> 00:24:23,250 by the gestures and the facial expressions 513 00:24:23,250 --> 00:24:25,040 of the great apes. 514 00:24:25,040 --> 00:24:27,460 Our tendency to project human behavior 515 00:24:27,460 --> 00:24:29,620 onto the ape's body language also makes 516 00:24:29,620 --> 00:24:31,990 subjective research difficult. 517 00:24:31,990 --> 00:24:33,690 One difference, however, is clear. 518 00:24:37,009 --> 00:24:37,842 (speaks in foreign language) 519 00:24:37,842 --> 00:24:39,590 One gesture we don't see the apes making 520 00:24:39,590 --> 00:24:42,030 is pointing with their index finger. 521 00:24:42,030 --> 00:24:44,283 Every gesture they make means the same thing. 522 00:24:45,150 --> 00:24:48,550 I want something now, meaning I want food. 523 00:24:48,550 --> 00:24:49,453 I want to play. 524 00:24:50,620 --> 00:24:52,070 I want you to leave me alone. 525 00:24:53,420 --> 00:24:54,253 I want to mate. 526 00:24:56,166 --> 00:24:57,290 But they don't use gestures to say, 527 00:24:57,290 --> 00:25:01,047 for example, "Look, did you see that bird up there?" 528 00:25:01,047 --> 00:25:04,107 "It's raining," or, "Do you want to go outside?" 529 00:25:05,900 --> 00:25:07,920 And apes are considerably worse than humans 530 00:25:07,920 --> 00:25:11,140 in understanding the co-operative potential of gestures. 531 00:25:11,140 --> 00:25:13,840 It's not in their nature to want to share information. 532 00:25:18,001 --> 00:25:20,584 (gentle music) 533 00:25:21,780 --> 00:25:24,610 Sharing one's own world with others. 534 00:25:24,610 --> 00:25:27,163 No species can do that better than humans. 535 00:25:28,260 --> 00:25:30,800 This new aspect to interhuman communication 536 00:25:30,800 --> 00:25:32,893 was an important step in our development. 537 00:25:35,240 --> 00:25:37,640 What makes us human is, largely, 538 00:25:37,640 --> 00:25:39,773 our ability to cooperate with others. 539 00:25:45,526 --> 00:25:46,359 (speaks in foreign language) 540 00:25:46,359 --> 00:25:47,360 When we look at large primates, 541 00:25:47,360 --> 00:25:49,370 it's worth asking ourselves, 542 00:25:49,370 --> 00:25:51,660 how do they differ from small children? 543 00:25:51,660 --> 00:25:53,760 We tend to think humans have a wonderful grasp 544 00:25:53,760 --> 00:25:55,620 of cause and effect relationships 545 00:25:55,620 --> 00:25:58,440 or can make complex predictions about the future, 546 00:25:58,440 --> 00:26:01,320 when in fact, apes and humans are pretty much alike. 547 00:26:01,320 --> 00:26:03,780 What humans excel at is any task that requires 548 00:26:03,780 --> 00:26:05,450 more than one person. 549 00:26:05,450 --> 00:26:07,770 In other words, we're better at coordinating our work, 550 00:26:07,770 --> 00:26:09,270 better at working together. 551 00:26:09,270 --> 00:26:11,150 And that is a tremendous advantage. 552 00:26:11,150 --> 00:26:14,430 Human children are great at not only dividing the work 553 00:26:14,430 --> 00:26:16,260 but they also understand that afterwards 554 00:26:16,260 --> 00:26:18,300 they have to divide the profits. 555 00:26:18,300 --> 00:26:20,280 So humans are good at anything that requires 556 00:26:20,280 --> 00:26:21,433 more than two people. 557 00:26:23,032 --> 00:26:25,080 (upbeat music) 558 00:26:25,080 --> 00:26:28,263 And only because of this was modern man able to build 559 00:26:28,263 --> 00:26:31,613 what we commonly know as human civilization. 560 00:26:34,967 --> 00:26:35,800 (speaks in foreign language) 561 00:26:35,800 --> 00:26:37,320 If we had to manage everything on our own 562 00:26:37,320 --> 00:26:40,070 as individuals, we wouldn't have any time for art 563 00:26:40,070 --> 00:26:43,980 or for building cities or palaces or whatever. 564 00:26:43,980 --> 00:26:45,650 Instead, we'd be worrying all the time about 565 00:26:45,650 --> 00:26:47,010 where our next meal is coming from 566 00:26:47,010 --> 00:26:49,580 or who's going to look after our kids. 567 00:26:49,580 --> 00:26:51,170 And it's only because we can delegate 568 00:26:51,170 --> 00:26:53,180 some of our responsibilities to others 569 00:26:53,180 --> 00:26:55,573 that we humans are able to achieve so much. 570 00:26:57,291 --> 00:26:59,160 (gentle music) 571 00:26:59,160 --> 00:27:00,890 But did this only become possible 572 00:27:00,890 --> 00:27:04,030 after a gene we call AHRGAP11B triggered 573 00:27:04,030 --> 00:27:05,830 the significant growth of our brain? 574 00:27:11,420 --> 00:27:12,650 To answer this question, 575 00:27:12,650 --> 00:27:15,520 the researchers at the Max Planck Institute in Dresden 576 00:27:15,520 --> 00:27:18,453 had to study the workings of the gene in more detail. 577 00:27:19,700 --> 00:27:21,720 The question was no longer if, 578 00:27:21,720 --> 00:27:25,023 but rather how 11B created more brain cells. 579 00:27:32,190 --> 00:27:35,040 What the scientists already knew was that 580 00:27:35,040 --> 00:27:37,890 AHRGAP11B is the partial duplication of a gene 581 00:27:37,890 --> 00:27:41,793 that also occurs in other mammals, AHRGAP11A. 582 00:27:43,680 --> 00:27:47,533 This duplication led to the creation of AHRGAP11B. 583 00:27:49,000 --> 00:27:51,740 This process only occurs in humans, however, 584 00:27:51,740 --> 00:27:53,283 and not in any other mammal. 585 00:27:57,358 --> 00:27:59,680 (speaks in foreign language) 586 00:27:59,680 --> 00:28:02,040 The partial duplication of the gene took place 587 00:28:02,040 --> 00:28:03,540 around five million years ago. 588 00:28:05,430 --> 00:28:07,010 But the brains of our hominid ancestors 589 00:28:07,010 --> 00:28:08,160 five million years ago 590 00:28:08,160 --> 00:28:10,350 were also very small in comparison. 591 00:28:10,350 --> 00:28:12,940 This means that this gene duplication cannot explain 592 00:28:12,940 --> 00:28:14,420 why our brains are so large, 593 00:28:14,420 --> 00:28:16,970 because they would have grown much earlier on, 594 00:28:16,970 --> 00:28:17,870 which they didn't. 595 00:28:19,637 --> 00:28:21,031 (dramatic music) 596 00:28:21,031 --> 00:28:24,300 In other words, the duplication of gene 11A to gene 11B 597 00:28:25,230 --> 00:28:26,463 had no initial effect. 598 00:28:27,570 --> 00:28:31,380 When 11B came into existence some 5 million years ago, 599 00:28:31,380 --> 00:28:33,573 modern man was still a long way off. 600 00:28:36,152 --> 00:28:36,985 (speaks in foreign language) 601 00:28:36,985 --> 00:28:37,920 What humans are particularly good at 602 00:28:37,920 --> 00:28:40,350 is putting themselves in other people's position. 603 00:28:40,350 --> 00:28:42,340 We call it the theory of the mind. 604 00:28:42,340 --> 00:28:45,340 Other animals can do it too, but we do it particularly well. 605 00:28:47,263 --> 00:28:49,846 (upbeat music) 606 00:28:51,138 --> 00:28:52,730 The scientists at the Max Planck Institute 607 00:28:52,730 --> 00:28:56,080 for Evolutionary Anthropology in Leipzig are studying 608 00:28:56,080 --> 00:28:57,653 the development of hominids. 609 00:29:01,560 --> 00:29:04,490 Doctor Phillip Guntz is a paleo-anthropologist 610 00:29:04,490 --> 00:29:07,430 and an expert on what our earliest ancestors looked like 611 00:29:07,430 --> 00:29:08,853 five million years ago. 612 00:29:10,176 --> 00:29:11,650 (speaks in foreign language) 613 00:29:11,650 --> 00:29:14,040 The ancestors of the Australopithecus 614 00:29:14,040 --> 00:29:16,223 left in Africa five million years ago. 615 00:29:17,660 --> 00:29:19,980 Australopithecus is a genus of hominin best known 616 00:29:19,980 --> 00:29:23,113 from the famous Lucy, who was discovered in the 1970s. 617 00:29:24,050 --> 00:29:25,880 From Lucy and her contemporaries, 618 00:29:25,880 --> 00:29:27,660 we know that they walked upright 619 00:29:27,660 --> 00:29:29,883 and lived on the Savannah of Eastern Africa. 620 00:29:33,360 --> 00:29:35,220 Not until the start of the human lineage 621 00:29:35,220 --> 00:29:37,030 around two million years ago 622 00:29:37,030 --> 00:29:39,453 do we see brain volume beginning to increase. 623 00:29:41,342 --> 00:29:42,175 (upbeat music) 624 00:29:42,175 --> 00:29:46,000 But if, for millions of years, gene 11B failed to trigger 625 00:29:46,000 --> 00:29:48,610 any increase in human brain size, 626 00:29:48,610 --> 00:29:50,490 why did the brain's stem cells suddenly 627 00:29:50,490 --> 00:29:52,303 begin to multiply so quickly? 628 00:29:55,530 --> 00:29:58,740 The Dresden scientists found the answer to this question 629 00:29:58,740 --> 00:30:00,373 inside the gene itself. 630 00:30:01,580 --> 00:30:05,200 A minuscule change, known as a point mutation, 631 00:30:05,200 --> 00:30:08,373 which gave 11B a completely new function. 632 00:30:09,682 --> 00:30:10,870 (speaks in foreign language) 633 00:30:10,870 --> 00:30:13,060 We managed to rebuild and test the gene, 634 00:30:13,060 --> 00:30:16,050 as it originally came to exist 5 million years ago, 635 00:30:16,050 --> 00:30:17,690 through duplication. 636 00:30:17,690 --> 00:30:20,050 It doesn't do anything on its own. 637 00:30:20,050 --> 00:30:22,150 It is only via the point mutation 638 00:30:22,150 --> 00:30:24,590 that the unique characteristic of this gene, 639 00:30:24,590 --> 00:30:27,270 it's ability to enlarge the brain, comes about, 640 00:30:27,270 --> 00:30:29,070 during the development of the fetus. 641 00:30:30,210 --> 00:30:32,490 And we are convinced that this point mutation occurred 642 00:30:32,490 --> 00:30:34,960 much later than 5 million years ago, 643 00:30:34,960 --> 00:30:38,150 probably more around one and a half million years ago, 644 00:30:38,150 --> 00:30:40,930 when there was this enormous boost in brain size development 645 00:30:40,930 --> 00:30:44,823 in the human lineage. 646 00:30:45,957 --> 00:30:46,790 (dramatic music) 647 00:30:46,790 --> 00:30:51,310 This sudden genetic mutation in AHRGAP11B was as unlikely 648 00:30:51,310 --> 00:30:53,893 as a lottery ticket with six matching numbers. 649 00:30:54,990 --> 00:30:58,120 Point mutations alter only one of several thousand 650 00:30:58,120 --> 00:31:00,523 nucleotide bases inside a gene. 651 00:31:01,410 --> 00:31:04,380 In 11B, this coincidence led to a change 652 00:31:04,380 --> 00:31:07,130 in the transcription process of the RNA 653 00:31:07,130 --> 00:31:09,333 and thus to a completely new effect. 654 00:31:10,770 --> 00:31:13,770 Due to the mutation, 11B received the signal 655 00:31:13,770 --> 00:31:17,270 to migrate from the cell nucleus into the mitochondria, 656 00:31:17,270 --> 00:31:19,750 where the cell produces its energy. 657 00:31:19,750 --> 00:31:22,530 And once there, it ensured that the stem cells 658 00:31:22,530 --> 00:31:24,543 would divide much more frequently, 659 00:31:25,430 --> 00:31:27,870 which meant, in short, that humans gained 660 00:31:27,870 --> 00:31:29,403 a much larger hard drive. 661 00:31:36,360 --> 00:31:37,390 The Dresden scientists had found 662 00:31:37,390 --> 00:31:40,060 the proverbial needle in a haystack, 663 00:31:40,060 --> 00:31:42,310 because mutations like this have taken place 664 00:31:42,310 --> 00:31:45,260 millions of times throughout human evolution, 665 00:31:45,260 --> 00:31:47,413 but mostly without any consequences. 666 00:31:48,977 --> 00:31:50,270 (speaks in foreign language) 667 00:31:50,270 --> 00:31:51,990 There are many kinds of mutations 668 00:31:51,990 --> 00:31:53,620 in the human body. 669 00:31:53,620 --> 00:31:56,140 Everybody carries mutations inside them, 670 00:31:56,140 --> 00:31:59,103 which can give rise to benign or malignant tumors. 671 00:32:00,010 --> 00:32:03,240 However, most mutations don't make any difference. 672 00:32:03,240 --> 00:32:05,940 Only very few of them actually have a positive effect, 673 00:32:07,100 --> 00:32:10,310 and natural selection only heeds positive changes. 674 00:32:10,310 --> 00:32:11,930 These are the changes that can survive 675 00:32:11,930 --> 00:32:13,853 the entire evolutionary process. 676 00:32:15,170 --> 00:32:17,860 We know that there are a lot of genetic similarities 677 00:32:17,860 --> 00:32:21,160 between modern humans and our closest living relatives, 678 00:32:21,160 --> 00:32:23,203 the bonobos and the chimpanzees. 679 00:32:24,160 --> 00:32:25,970 And what that means is that often 680 00:32:25,970 --> 00:32:28,620 very small differences can have a substantial effect. 681 00:32:30,313 --> 00:32:32,450 (upbeat music) 682 00:32:32,450 --> 00:32:34,763 The growing brain needs more space. 683 00:32:35,800 --> 00:32:38,730 So how did our ancestors' boney skulls adapt 684 00:32:38,730 --> 00:32:39,943 to the larger brain? 685 00:32:43,636 --> 00:32:45,670 (speaks in foreign language) 686 00:32:45,670 --> 00:32:48,740 Here, we can reach a pretty clear conclusion. 687 00:32:48,740 --> 00:32:51,443 This is a 3D model of a human baby's skull. 688 00:32:55,860 --> 00:32:58,670 The fontanelle is still open directly after birth 689 00:32:58,670 --> 00:33:00,873 and the bones are not yet fused together. 690 00:33:03,830 --> 00:33:07,063 As the brain expands, it pushes the skull outwards. 691 00:33:08,200 --> 00:33:10,060 At this early stage of development, 692 00:33:10,060 --> 00:33:12,530 the increasing volume of the brain is what drives 693 00:33:12,530 --> 00:33:13,730 the growth of the skull. 694 00:33:16,805 --> 00:33:19,250 (upbeat music) 695 00:33:19,250 --> 00:33:22,680 In 2011, researchers from the Max Planck Institute 696 00:33:22,680 --> 00:33:25,760 for Evolutionary Anthropology managed to decode 697 00:33:25,760 --> 00:33:28,363 the Neanderthal genome for the first time. 698 00:33:29,870 --> 00:33:32,610 As the data shows, Neanderthals also possess 699 00:33:32,610 --> 00:33:35,390 the mutated AHRGAP11B gene, 700 00:33:35,390 --> 00:33:38,253 and had a brain of similar size to modern humans. 701 00:33:39,740 --> 00:33:42,530 This suggests that the point mutation of 11B 702 00:33:42,530 --> 00:33:44,690 must have taken place before the development 703 00:33:44,690 --> 00:33:45,723 of the Neanderthals. 704 00:33:49,011 --> 00:33:50,950 (speaks in foreign language) 705 00:33:50,950 --> 00:33:53,030 We know for a fact that modern man 706 00:33:53,030 --> 00:33:56,210 and Neanderthals share a common ancestor, 707 00:33:56,210 --> 00:34:01,210 who was alive at least 600,000 years ago. 708 00:34:02,990 --> 00:34:03,823 (lively music) 709 00:34:03,823 --> 00:34:06,203 This ancestor was homo erectus. 710 00:34:07,210 --> 00:34:10,830 The point mutation of gene 11B presumably started 711 00:34:10,830 --> 00:34:12,543 in a member of this species. 712 00:34:16,643 --> 00:34:19,000 (speaks in foreign language) 713 00:34:19,000 --> 00:34:21,680 Homo erectus is the first human ancestor 714 00:34:21,680 --> 00:34:24,200 to have lived throughout the old world, 715 00:34:24,200 --> 00:34:26,733 meaning Africa, Europe, and Asia. 716 00:34:28,540 --> 00:34:31,453 They didn't make it to the Americas, as far as we know. 717 00:34:33,250 --> 00:34:35,480 They had brains that were more than double the size 718 00:34:35,480 --> 00:34:37,743 of those of the great apes alive today. 719 00:34:40,790 --> 00:34:43,580 Homo erectus was a talented hunter-gatherer 720 00:34:43,580 --> 00:34:46,443 and probably hunted large prey using spears. 721 00:34:49,749 --> 00:34:52,120 (lively music) 722 00:34:52,120 --> 00:34:54,410 However, it does not appear that the results 723 00:34:54,410 --> 00:34:57,000 of this genetic mutations spread like wildfire 724 00:34:57,000 --> 00:34:58,283 throughout the species. 725 00:35:04,365 --> 00:35:06,520 (speaks in foreign language) 726 00:35:06,520 --> 00:35:09,080 Without knowing exactly how this gene works, 727 00:35:09,080 --> 00:35:11,200 we can assume that its effects were not 728 00:35:11,200 --> 00:35:13,003 particularly dramatic at the start, 729 00:35:15,620 --> 00:35:17,860 because natural selection normally filters out 730 00:35:17,860 --> 00:35:19,283 any extreme changes. 731 00:35:22,380 --> 00:35:25,980 Brain volume in humans constantly double overnight. 732 00:35:25,980 --> 00:35:29,140 Brains that size require a lot of energy 733 00:35:29,140 --> 00:35:30,880 and energy is the currency, so to speak, 734 00:35:30,880 --> 00:35:31,973 that nature deals in. 735 00:35:32,850 --> 00:35:36,310 An organism has to be able to afford such a large brain. 736 00:35:36,310 --> 00:35:39,130 We think homo erectus could sustain a brain of this size 737 00:35:39,130 --> 00:35:41,520 because it consumed a very high-energy diet 738 00:35:41,520 --> 00:35:43,510 through its highly effective hunting methods, 739 00:35:43,510 --> 00:35:45,410 and therefore had a surplus of energy. 740 00:35:46,370 --> 00:35:49,410 So we can assume that the increase in brain size was 741 00:35:49,410 --> 00:35:52,413 a gradual change that took place in early childhood. 742 00:35:54,688 --> 00:35:57,070 (lively music) 743 00:35:57,070 --> 00:35:59,180 Our forefathers' direct descendants, therefore, 744 00:35:59,180 --> 00:36:01,870 had more neurons at their disposal, 745 00:36:01,870 --> 00:36:04,420 allowing them to develop their cognitive abilities. 746 00:36:09,607 --> 00:36:10,440 (speaks in foreign language) 747 00:36:10,440 --> 00:36:11,670 There are some basic conditions 748 00:36:11,670 --> 00:36:13,670 that we need to meet in order to get the most 749 00:36:13,670 --> 00:36:15,450 out of this large brain. 750 00:36:15,450 --> 00:36:18,420 The first is that you have to be able to sustain the brain. 751 00:36:18,420 --> 00:36:20,680 That means we need the food, we need the energy 752 00:36:20,680 --> 00:36:23,200 so that this brain can keep working. 753 00:36:23,200 --> 00:36:25,290 Then we need to network with others. 754 00:36:25,290 --> 00:36:27,760 That means that we really have to use the first years 755 00:36:27,760 --> 00:36:29,850 of our life to learn from other people, 756 00:36:29,850 --> 00:36:32,320 because there's an incredible amount in human society 757 00:36:32,320 --> 00:36:33,720 that we have to understand, 758 00:36:33,720 --> 00:36:36,380 in terms of what we can or cannot do. 759 00:36:36,380 --> 00:36:39,680 Otherwise we risk being excluded from society later on. 760 00:36:39,680 --> 00:36:42,030 As individuals, we will not get far on our own. 761 00:36:43,812 --> 00:36:46,395 (upbeat music) 762 00:36:48,020 --> 00:36:51,610 The random mutation of AHRGAP11B was clearly 763 00:36:51,610 --> 00:36:54,090 such an enormous evolutionary advantage 764 00:36:54,090 --> 00:36:55,930 that the mutated gene was passed on 765 00:36:55,930 --> 00:36:58,170 to all of homo erectus' descendants, 766 00:36:58,170 --> 00:37:01,163 and therefore to the entire human race. 767 00:37:03,040 --> 00:37:05,730 If the carrier of the mutated gene had died 768 00:37:05,730 --> 00:37:08,570 in the plains of Africa without any offspring, 769 00:37:08,570 --> 00:37:10,683 modern man would probably not exist. 770 00:37:14,716 --> 00:37:17,299 (gentle music) 771 00:37:21,930 --> 00:37:25,430 What the homo genus did with this random coincidence, 772 00:37:25,430 --> 00:37:27,790 and what sets it apart from its forefathers 773 00:37:27,790 --> 00:37:30,270 is also being studied by the primatological 774 00:37:30,270 --> 00:37:32,413 at the Max Planck Institute in Leipzig. 775 00:37:34,598 --> 00:37:37,620 {\an8}(speaks in foreign language) 776 00:37:37,620 --> 00:37:39,930 {\an8}What sets humans apart is language, 777 00:37:39,930 --> 00:37:41,243 {\an8}symbolic communication. 778 00:37:42,750 --> 00:37:45,330 No other creatures can express their feelings, 779 00:37:45,330 --> 00:37:46,700 their thoughts, and their wishes 780 00:37:46,700 --> 00:37:48,100 in the same way that we can. 781 00:37:51,073 --> 00:37:51,906 (gentle music) 782 00:37:51,906 --> 00:37:55,530 Dr. Roman Wittig is the director of the chimpanzee project 783 00:37:55,530 --> 00:37:58,233 in the Thai National Park in Ivory Coast. 784 00:37:59,150 --> 00:38:01,930 Observing chimpanzees in their natural habitat 785 00:38:01,930 --> 00:38:03,690 has given researchers some insights 786 00:38:03,690 --> 00:38:06,413 into the evolutionary basis of human behavior. 787 00:38:07,768 --> 00:38:11,200 (speaks in foreign language) 788 00:38:11,200 --> 00:38:13,510 Around seven to eight million years ago, 789 00:38:13,510 --> 00:38:16,193 some of our ancestors went out into the Savannah. 790 00:38:18,310 --> 00:38:20,120 They had to face new challenges, 791 00:38:20,120 --> 00:38:23,090 and the pressures of natural selection were so strong 792 00:38:23,090 --> 00:38:25,580 that a substantial change took place, 793 00:38:25,580 --> 00:38:27,933 which ultimately led to modern man. 794 00:38:29,010 --> 00:38:31,300 While the remainder of our ancestors stayed 795 00:38:31,300 --> 00:38:33,900 where they had always been, in the forest, 796 00:38:33,900 --> 00:38:35,743 in the tropical forests of Africa. 797 00:38:40,600 --> 00:38:43,290 The processes of selection that affected these apes 798 00:38:43,290 --> 00:38:45,060 were much more conservative, 799 00:38:45,060 --> 00:38:48,143 and that is why evolution was more limited in their case. 800 00:38:50,010 --> 00:38:52,940 We can therefore assume that the behavior of our ancestors 801 00:38:52,940 --> 00:38:56,370 some seven to eight million years ago was far closer 802 00:38:56,370 --> 00:38:58,450 to that of chimpanzees than it would be 803 00:38:58,450 --> 00:38:59,923 to our behavior today. 804 00:39:01,180 --> 00:39:04,500 That's why it makes sense to study these animals closely, 805 00:39:04,500 --> 00:39:07,623 in order to understand where we as a species come from. 806 00:39:13,530 --> 00:39:16,200 These studies have shown that we have much more in common 807 00:39:16,200 --> 00:39:18,163 with chimpanzees than we realize. 808 00:39:19,840 --> 00:39:23,270 They too form social units, share food, 809 00:39:23,270 --> 00:39:27,923 maintain friendships, show empathy, use tools, communicate, 810 00:39:29,290 --> 00:39:30,623 and probably dream. 811 00:39:32,360 --> 00:39:34,460 Groups of chimpanzees have even been shown 812 00:39:34,460 --> 00:39:36,633 to form their own individual cultures. 813 00:39:37,786 --> 00:39:40,530 (speaks in foreign language) 814 00:39:40,530 --> 00:39:42,440 We have studied chimpanzee cultures 815 00:39:42,440 --> 00:39:45,530 for the first time, by looking at behavioral variations 816 00:39:49,826 --> 00:39:52,740 We found, for example, that although there are kuna nuts 817 00:39:52,740 --> 00:39:54,560 all over West Africa, 818 00:39:54,560 --> 00:39:57,940 only part of the chimpanzee population cracks these nuts 819 00:39:57,940 --> 00:39:58,813 in this area. 820 00:40:02,930 --> 00:40:03,833 And why is this? 821 00:40:04,840 --> 00:40:06,743 There is no ecological reason for it, 822 00:40:07,827 --> 00:40:09,910 and there's no genetic reason for it. 823 00:40:09,910 --> 00:40:11,313 So what is the reason? 824 00:40:12,480 --> 00:40:14,070 It's how the chimpanzees show 825 00:40:14,070 --> 00:40:16,110 which social group they belong to, 826 00:40:16,110 --> 00:40:17,560 which culture they belong to. 827 00:40:18,720 --> 00:40:21,800 Just like we do when we eat rice with chopsticks 828 00:40:21,800 --> 00:40:23,513 or a fork, or with our hands. 829 00:40:27,088 --> 00:40:29,671 (gentle music) 830 00:40:31,285 --> 00:40:32,120 (speaks in foreign language) 831 00:40:32,120 --> 00:40:33,897 We're the only species 832 00:40:33,897 --> 00:40:35,140 that carries tools around all day, 833 00:40:35,140 --> 00:40:36,890 and not just our mobile phones. 834 00:40:36,890 --> 00:40:39,140 In the past it was a pocket knife, a watch, 835 00:40:39,140 --> 00:40:41,310 even our clothes or glasses. 836 00:40:41,310 --> 00:40:43,470 These things become a part of who we are. 837 00:40:43,470 --> 00:40:45,320 So our culture is part of who we are. 838 00:40:46,721 --> 00:40:49,471 (dramatic music) 839 00:40:51,539 --> 00:40:53,780 But while the cultural evolution of our ape cousins 840 00:40:53,780 --> 00:40:55,460 came to a standstill, 841 00:40:55,460 --> 00:40:58,520 that of humans continued to develop exponentially 842 00:41:03,444 --> 00:41:04,277 (speaks in foreign language) 843 00:41:04,277 --> 00:41:05,670 If we looked at our evolutionary development 844 00:41:05,670 --> 00:41:07,970 as a curve, it would go like this. 845 00:41:07,970 --> 00:41:10,700 And that's something that Darwin alone cannot explain. 846 00:41:10,700 --> 00:41:13,360 This idea that the current generation must die out 847 00:41:13,360 --> 00:41:15,710 before we can take a few steps forward, 848 00:41:15,710 --> 00:41:18,260 and then after that, the next generation must die out, 849 00:41:18,260 --> 00:41:20,130 that won't help us to develop at the same rate 850 00:41:20,130 --> 00:41:23,060 we have managed to over the last 40,000 years. 851 00:41:23,060 --> 00:41:25,730 And all those things that we associate with humans, 852 00:41:25,730 --> 00:41:29,360 religion, culture, tools with small moving parts, 853 00:41:29,360 --> 00:41:30,940 these are all things that have been created 854 00:41:30,940 --> 00:41:33,280 in this very short period of time. 855 00:41:33,280 --> 00:41:35,910 The reason that we've evolved so fast as a species 856 00:41:35,910 --> 00:41:37,420 is that we don't have to invent everything 857 00:41:37,420 --> 00:41:39,180 from scratch each time. 858 00:41:39,180 --> 00:41:41,320 An engineering student doesn't have to figure out 859 00:41:41,320 --> 00:41:43,560 on their own how a steam engine works. 860 00:41:43,560 --> 00:41:46,350 We can build on knowledge that has been gained by others. 861 00:41:46,350 --> 00:41:49,023 So in a sense, cultural evolution is our evolution. 862 00:41:52,638 --> 00:41:55,300 (dramatic music) 863 00:41:55,300 --> 00:41:57,520 From I to we. 864 00:41:57,520 --> 00:41:59,530 Only humans are capable of uniting 865 00:41:59,530 --> 00:42:01,860 hundreds of thousands of their own species 866 00:42:01,860 --> 00:42:03,383 under a single idea. 867 00:42:05,800 --> 00:42:08,010 Only humans have managed to bring together 868 00:42:08,010 --> 00:42:10,893 and organized millions of others in one place. 869 00:42:13,500 --> 00:42:16,100 Our social intelligence was one of the key factors 870 00:42:16,100 --> 00:42:18,710 behind our remarkable development as a species 871 00:42:21,144 --> 00:42:23,100 (speaks in foreign language) 872 00:42:23,100 --> 00:42:25,570 So we believe that our social intelligence is 873 00:42:25,570 --> 00:42:28,170 not just a byproduct of our evolution, 874 00:42:28,170 --> 00:42:30,240 of our growth as a species, 875 00:42:30,240 --> 00:42:32,853 but actually one of the driving forces behind it. 876 00:42:34,805 --> 00:42:36,970 And the whole thing is then taken a step further 877 00:42:36,970 --> 00:42:39,750 by the cultural intelligence hypothesis, 878 00:42:39,750 --> 00:42:41,850 which basically says that the passing on 879 00:42:41,850 --> 00:42:43,640 of this cultural information, 880 00:42:43,640 --> 00:42:45,860 such as the mastery of fire and so on, 881 00:42:45,860 --> 00:42:48,523 is what has caused our brains to grow so much. 882 00:42:50,865 --> 00:42:53,615 (rhythmic music) 883 00:42:56,123 --> 00:42:58,230 So, what are our evolutionary advantages? 884 00:42:58,230 --> 00:42:59,570 We don't even have fire. 885 00:42:59,570 --> 00:43:01,680 We need to wear clothes to survive. 886 00:43:01,680 --> 00:43:04,430 We don't have claws or especially strong muscles. 887 00:43:04,430 --> 00:43:07,050 In fact, we have lost much of our original muscle mass, 888 00:43:07,050 --> 00:43:08,260 so we have the energy to feed 889 00:43:08,260 --> 00:43:10,110 our incredibly powerful brains. 890 00:43:10,110 --> 00:43:11,810 We're not built to survive on our own, 891 00:43:11,810 --> 00:43:15,530 but instead we've created a community that we can rely on. 892 00:43:15,530 --> 00:43:18,113 (upbeat music) 893 00:43:19,420 --> 00:43:21,550 We often think we've had enough of other people 894 00:43:21,550 --> 00:43:22,920 and that it will be nice to withdraw 895 00:43:22,920 --> 00:43:24,790 to a desert island somewhere. 896 00:43:24,790 --> 00:43:26,880 But we wouldn't survive on a desert island. 897 00:43:26,880 --> 00:43:28,620 We wouldn't manage to meet our own needs 898 00:43:28,620 --> 00:43:30,200 and we'd get very hungry. 899 00:43:30,200 --> 00:43:31,240 And that's the point. 900 00:43:31,240 --> 00:43:33,230 The community is a part of who we are 901 00:43:33,230 --> 00:43:35,433 and we would not exist without the community. 902 00:43:37,017 --> 00:43:38,390 (upbeat music) 903 00:43:38,390 --> 00:43:41,910 Living in groups provides protection, sustenance, 904 00:43:41,910 --> 00:43:43,193 and a sense of belonging. 905 00:43:44,170 --> 00:43:47,510 But it also creates competition for food, 906 00:43:47,510 --> 00:43:49,543 territory, and reproductive partners. 907 00:43:50,600 --> 00:43:52,853 This can cause friction and aggression. 908 00:43:58,011 --> 00:44:00,954 (speaks in foreign language) 909 00:44:00,954 --> 00:44:02,260 This competition needs to be managed 910 00:44:02,260 --> 00:44:03,740 in some way. 911 00:44:03,740 --> 00:44:06,560 Not everyone can eat the same piece of fruit. 912 00:44:06,560 --> 00:44:08,710 We have observed how chimpanzees follow 913 00:44:08,710 --> 00:44:11,480 a kind of decision-making process. 914 00:44:11,480 --> 00:44:14,870 They ask themselves, should I accept that another animal 915 00:44:14,870 --> 00:44:17,760 has this piece of fruit and that I can't have it? 916 00:44:17,760 --> 00:44:18,960 Should I share the fruit 917 00:44:20,220 --> 00:44:22,893 or should I hit him and steal the fruit for myself? 918 00:44:25,909 --> 00:44:27,750 Our early ancestors had different ways 919 00:44:27,750 --> 00:44:29,523 of resolving aggressive conflict. 920 00:44:30,510 --> 00:44:33,933 Similar methods can be observed in chimpanzees to this day. 921 00:44:34,936 --> 00:44:37,188 (chimps hooting) 922 00:44:37,188 --> 00:44:38,021 (speaks in foreign language) 923 00:44:38,021 --> 00:44:39,800 When chimpanzees get into conflicts 924 00:44:39,800 --> 00:44:42,583 over borders, a number of different things can happen. 925 00:44:43,800 --> 00:44:46,850 The first thing is that they detect the other animals 926 00:44:46,850 --> 00:44:48,153 and a loud fight ensues. 927 00:44:52,280 --> 00:44:53,730 They beat the roots of the trees 928 00:44:53,730 --> 00:44:56,253 and make pant hoots and pant roars. 929 00:44:58,655 --> 00:44:59,488 These are very loud calls 930 00:44:59,488 --> 00:45:01,263 that can be heard for miles around. 931 00:45:05,251 --> 00:45:09,168 (chimp hooting and screaming) 932 00:45:11,230 --> 00:45:13,560 And usually, these battle cries are enough 933 00:45:13,560 --> 00:45:16,203 to determine which of the two groups should retreat. 934 00:45:21,730 --> 00:45:23,920 But sometimes this is not enough, 935 00:45:23,920 --> 00:45:26,460 and the chimpanzees confront each other to show 936 00:45:26,460 --> 00:45:29,530 how big their group is, who is taller, 937 00:45:29,530 --> 00:45:31,173 who is stronger, and so on. 938 00:45:33,812 --> 00:45:36,729 (chimps screaming) 939 00:45:40,180 --> 00:45:43,670 And sometimes, these direct physical fights take place, 940 00:45:43,670 --> 00:45:46,683 which can result in injuries or even deaths. 941 00:45:56,084 --> 00:45:57,950 What we haven't observed so far in these fights, 942 00:45:57,950 --> 00:45:59,943 however, is the use of weapons. 943 00:46:05,941 --> 00:46:08,310 Although chimpanzees understand how to crack a nut 944 00:46:08,310 --> 00:46:12,590 using a stone, we've never seen them use weapons like this 945 00:46:12,590 --> 00:46:14,820 in their conflicts with other animals. 946 00:46:21,202 --> 00:46:22,035 (dramatic music) 947 00:46:22,035 --> 00:46:26,690 Unlike humans, conflicts are a part of everyday life 948 00:46:26,690 --> 00:46:28,223 for all primate groups. 949 00:46:29,530 --> 00:46:32,370 Waging war with deadly weapons, however, 950 00:46:32,370 --> 00:46:35,120 is an invention of modern man. 951 00:46:35,120 --> 00:46:37,710 This is the other side of our species' social 952 00:46:37,710 --> 00:46:39,113 and cultural cognition. 953 00:46:42,197 --> 00:46:44,864 (bomb blasting) 954 00:46:48,574 --> 00:46:51,157 (upbeat music) 955 00:46:53,470 --> 00:46:56,570 Can the genetic researchers from Dresden imagine apes 956 00:46:56,570 --> 00:47:00,030 with the AHRGAP11B gene also becoming like humans 957 00:47:00,030 --> 00:47:00,963 in this respect? 958 00:47:02,400 --> 00:47:04,890 Under research director Dr. Wieland Huttner, 959 00:47:04,890 --> 00:47:07,223 this question will never be put to the test. 960 00:47:09,674 --> 00:47:11,862 (speaks in foreign language) 961 00:47:11,862 --> 00:47:13,950 No, tests on apes and not allowed. 962 00:47:13,950 --> 00:47:15,610 And with good reason. 963 00:47:15,610 --> 00:47:18,100 These animals are very close to us, 964 00:47:18,100 --> 00:47:19,660 and I think it's absolutely right 965 00:47:19,660 --> 00:47:22,540 that they should be off-limits for such experiments. 966 00:47:22,540 --> 00:47:24,160 I think it would be highly irresponsible 967 00:47:24,160 --> 00:47:26,610 to manipulate orangutans or chimpanzees 968 00:47:26,610 --> 00:47:27,893 or gorillas in this way. 969 00:47:31,403 --> 00:47:32,236 (speaks in foreign language) 970 00:47:32,236 --> 00:47:33,456 How old is Tony now? 971 00:47:33,456 --> 00:47:34,289 (speaks in foreign language) 972 00:47:34,289 --> 00:47:35,430 Tony's 28. 973 00:47:35,430 --> 00:47:38,672 He was born on the 13th of December, 1991. 974 00:47:38,672 --> 00:47:40,576 (dramatic music) 975 00:47:40,576 --> 00:47:42,980 Dr. Huttner also rules out any further application 976 00:47:42,980 --> 00:47:46,823 of their research results, either for apes or for humans. 977 00:47:48,308 --> 00:47:50,664 (speaks in foreign language) 978 00:47:50,664 --> 00:47:51,680 What is out of the question for me 979 00:47:51,680 --> 00:47:53,940 as a medical scientist, I repeat, 980 00:47:53,940 --> 00:47:55,960 absolutely out of the question 981 00:47:55,960 --> 00:47:59,920 is any attempt to quote/unquote "enhance human brains" 982 00:47:59,920 --> 00:48:03,160 by, let's say, smuggling in a second 11B gene 983 00:48:03,160 --> 00:48:05,850 or a more effective 11B gene. 984 00:48:05,850 --> 00:48:08,360 I would consider this to be highly irresponsible. 985 00:48:08,360 --> 00:48:09,950 You have to be quite clear, 986 00:48:09,950 --> 00:48:12,153 human brains are not necessarily better. 987 00:48:13,330 --> 00:48:15,300 My research has been about finding out 988 00:48:15,300 --> 00:48:17,270 why we have a large brain. 989 00:48:17,270 --> 00:48:19,320 I think this is a fundamental question, 990 00:48:19,320 --> 00:48:21,720 because it helps us to understand why we humans 991 00:48:21,720 --> 00:48:22,793 are the way we are. 992 00:48:24,429 --> 00:48:27,029 But to find some way of applying these findings, no. 993 00:48:29,288 --> 00:48:30,920 (gentle music) 994 00:48:30,920 --> 00:48:32,930 Although the findings from Dresden 995 00:48:32,930 --> 00:48:35,040 won't be tested on living people, 996 00:48:35,040 --> 00:48:36,760 the results are so compelling 997 00:48:36,760 --> 00:48:39,350 that they leave little room for doubt. 998 00:48:39,350 --> 00:48:41,250 Yet, the researchers are still looking 999 00:48:41,250 --> 00:48:43,113 for further proof of their theory. 1000 00:48:44,510 --> 00:48:45,710 (speaks in foreign language) 1001 00:48:45,710 --> 00:48:47,980 We now have proof that 11B can increase 1002 00:48:47,980 --> 00:48:49,500 the size of the brain. 1003 00:48:49,500 --> 00:48:52,100 And that's what Michel Heide's work has shown us. 1004 00:48:52,100 --> 00:48:53,930 But there is no data so far to tell us 1005 00:48:53,930 --> 00:48:57,040 what happens if 11B is missing in humans. 1006 00:48:57,040 --> 00:48:59,450 Would these people have smaller brains? 1007 00:48:59,450 --> 00:49:01,180 There haven't been any humans in whom 1008 00:49:01,180 --> 00:49:03,250 11B is completely lacking. 1009 00:49:03,250 --> 00:49:05,050 That's in itself tells us something. 1010 00:49:07,754 --> 00:49:09,115 (speaks in foreign language) 1011 00:49:09,115 --> 00:49:10,070 I don't think we can go any farther 1012 00:49:10,070 --> 00:49:13,073 in terms of introducing this gene into other organisms. 1013 00:49:13,940 --> 00:49:16,240 Another way, of course, would be to look for patients 1014 00:49:16,240 --> 00:49:19,040 who either have mutations in AHRGAP11B 1015 00:49:19,040 --> 00:49:20,590 or some kind of loss, 1016 00:49:20,590 --> 00:49:22,540 and to see what their brains look like. 1017 00:49:23,890 --> 00:49:26,140 This could of course be done noninvasively, 1018 00:49:26,140 --> 00:49:28,173 using MRI or something like that. 1019 00:49:31,236 --> 00:49:32,580 (gentle music) 1020 00:49:32,580 --> 00:49:35,330 A way of using their findings will be left to others 1021 00:49:35,330 --> 00:49:39,700 to figure out over the coming years, or even generations. 1022 00:49:39,700 --> 00:49:42,713 But Michel Heide's research work is far from over. 1023 00:49:44,454 --> 00:49:45,287 (speaks in foreign language) 1024 00:49:45,287 --> 00:49:47,160 We don't just have this one gene. 1025 00:49:47,160 --> 00:49:49,440 Michel Haida has discovered 14 others 1026 00:49:49,440 --> 00:49:51,050 that are specific to humans 1027 00:49:51,050 --> 00:49:53,160 and that are highly active in stem cells, 1028 00:49:53,160 --> 00:49:54,560 that're sure to be a backup. 1029 00:49:56,238 --> 00:49:57,670 (speaks in foreign language) 1030 00:49:57,670 --> 00:49:59,640 And another interesting question for me is, 1031 00:49:59,640 --> 00:50:02,610 there are 15 genes, are there natural interactions 1032 00:50:02,610 --> 00:50:03,970 between these genes? 1033 00:50:03,970 --> 00:50:05,860 Are there networks that overlap? 1034 00:50:05,860 --> 00:50:08,280 How do these genes interact with each other? 1035 00:50:08,280 --> 00:50:09,820 This is another exciting question 1036 00:50:09,820 --> 00:50:11,220 that remains to be answered. 1037 00:50:12,962 --> 00:50:15,080 (dramatic music) 1038 00:50:15,080 --> 00:50:17,600 If the research findings of the Dresden scientists 1039 00:50:17,600 --> 00:50:20,897 can be substantiated over the next few years, 1040 00:50:20,897 --> 00:50:23,470 Wieland Huttner could one day experience the completion 1041 00:50:23,470 --> 00:50:24,453 of his life's work, 1042 00:50:25,780 --> 00:50:29,620 a comprehensive theory about the growth of the human brain, 1043 00:50:29,620 --> 00:50:33,163 an essential piece of the puzzle that is human evolution. 1044 00:50:38,760 --> 00:50:40,810 A world-changing coincidence 1045 00:50:40,810 --> 00:50:44,060 that many hundreds of thousands of years ago 1046 00:50:44,060 --> 00:50:47,713 made the miracle of homo sapiens sapiens possible. 1047 00:51:01,826 --> 00:51:04,620 (gentle piano music) 1048 00:51:04,620 --> 00:51:07,921 ♪ 11B, 11B, ♪ 1049 00:51:07,921 --> 00:51:11,826 ♪ 11B, 11B ♪ 1050 00:51:11,826 --> 00:51:15,826 ♪ Speaking words of wisdom, 11B ♪ 1051 00:51:29,635 --> 00:51:33,378 ♪ 11B, 11B ♪ 1052 00:51:33,378 --> 00:51:37,441 ♪ 11B, 11B ♪ 1053 00:51:37,441 --> 00:51:41,441 ♪ Speaking words of wisdom, 11B ♪