1 00:00:01,233 --> 00:00:03,766 ♪ 2 00:00:05,766 --> 00:00:09,300 NARRATOR: For centuries, the best clues to ancient life 3 00:00:09,300 --> 00:00:12,000 have come from fossils. 4 00:00:13,333 --> 00:00:17,600 But now, a new window on the past is opening. 5 00:00:17,600 --> 00:00:19,966 ESKE WILLERSLEV: How can we travel back in time? 6 00:00:19,966 --> 00:00:21,766 Is there a time machine? 7 00:00:22,966 --> 00:00:26,300 Yes. It's DNA. 8 00:00:26,300 --> 00:00:29,100 It's ancient DNA. 9 00:00:30,066 --> 00:00:31,833 MAANASA RAGHAVAN: These are fragile molecules 10 00:00:31,833 --> 00:00:33,400 that fall apart outside the body. 11 00:00:34,633 --> 00:00:36,633 NARRATOR: How long can DNA survive? 12 00:00:36,633 --> 00:00:39,500 With ancient DNA, we're trying to go back in time. 13 00:00:40,900 --> 00:00:43,933 But time is the enemy. 14 00:00:43,933 --> 00:00:45,833 ♪ 15 00:00:45,833 --> 00:00:49,600 NARRATOR: A dramatic breakthrough is transporting us 16 00:00:49,600 --> 00:00:52,166 millions of years back into the past, 17 00:00:52,166 --> 00:00:56,100 to before the last Ice Age-- 18 00:00:56,100 --> 00:00:59,900 revealing surprising creatures that thrived 19 00:00:59,900 --> 00:01:02,066 when our planet was far warmer than it is today. 20 00:01:02,066 --> 00:01:04,133 (birds cawing) 21 00:01:04,133 --> 00:01:06,333 Could ancient genes from this lost world 22 00:01:06,333 --> 00:01:09,466 help us adapt to a changing planet? 23 00:01:09,466 --> 00:01:11,133 (drill whirring) 24 00:01:11,133 --> 00:01:16,733 ♪ 25 00:01:16,733 --> 00:01:21,166 WILLERSLEV: We are stealing genetic secrets of the past... 26 00:01:22,566 --> 00:01:25,033 ...so we can rescue the future. 27 00:01:25,033 --> 00:01:27,866 ♪ 28 00:01:27,866 --> 00:01:32,666 NARRATOR: Go behind the scenes on the "Hunt for the Oldest DNA." 29 00:01:32,666 --> 00:01:34,300 ♪ 30 00:01:34,300 --> 00:01:36,400 Right now, on "NOVA." 31 00:01:36,400 --> 00:01:40,866 ♪ 32 00:01:59,766 --> 00:02:02,133 NARRATOR: Buried beneath Greenland's ice sheet 33 00:02:02,133 --> 00:02:06,233 are the remains of a living world that ended 34 00:02:06,233 --> 00:02:11,400 when the Ice Age began-- over two million years ago. 35 00:02:11,400 --> 00:02:13,800 One scientist is on a quest 36 00:02:13,800 --> 00:02:16,633 to reveal that lost world 37 00:02:16,633 --> 00:02:18,600 with ancient DNA. 38 00:02:20,466 --> 00:02:22,700 WILLERSLEV: When I look at this place, 39 00:02:22,700 --> 00:02:26,766 I see one huge cold storage room for ancient DNA. 40 00:02:26,766 --> 00:02:28,900 ♪ 41 00:02:28,900 --> 00:02:31,633 I spent my life trying to find older and older DNA. 42 00:02:31,633 --> 00:02:35,066 And this is the limit of the possible. 43 00:02:35,066 --> 00:02:37,600 And maybe it's impossible. 44 00:02:38,900 --> 00:02:40,433 What we are trying to recover 45 00:02:40,433 --> 00:02:45,400 is DNA millions of years older than any DNA ever recovered. 46 00:02:45,400 --> 00:02:47,933 So we are trying to reach back 47 00:02:47,933 --> 00:02:50,233 before the last Ice Age. 48 00:02:50,233 --> 00:02:52,633 ♪ 49 00:02:52,633 --> 00:02:54,533 NARRATOR: Once, fossils were our only hope 50 00:02:54,533 --> 00:02:58,233 of shedding light on life in the distant past. 51 00:02:58,233 --> 00:03:00,833 But ever since scientists first recovered DNA 52 00:03:00,833 --> 00:03:05,266 from an extinct animal 40 years ago, 53 00:03:05,266 --> 00:03:09,266 fossil hunters have been sharing the stage with gene hunters. 54 00:03:09,266 --> 00:03:13,833 We've peered into a fascinating world of extinct species, 55 00:03:13,833 --> 00:03:18,633 Ice Age beasts, even our Neanderthal cousins. 56 00:03:18,633 --> 00:03:19,900 SHAPIRO: When I look back in time, 57 00:03:19,900 --> 00:03:21,366 the sharpest tool I have 58 00:03:21,366 --> 00:03:24,800 is DNA-- the genes of long dead plants and animals. 59 00:03:24,800 --> 00:03:26,600 This is a far more detailed record 60 00:03:26,600 --> 00:03:30,366 of the past than the fossils alone can ever give us. 61 00:03:30,366 --> 00:03:32,666 NARRATOR: But the older DNA gets, 62 00:03:32,666 --> 00:03:35,133 the fainter the signal. 63 00:03:35,133 --> 00:03:39,533 The moment a living thing dies, its DNA starts falling apart. 64 00:03:39,533 --> 00:03:42,633 Of course, we are never going to stop wondering, 65 00:03:42,633 --> 00:03:44,666 "Exactly how far back can we go?" 66 00:03:44,666 --> 00:03:47,500 What is the limit of DNA preservation? 67 00:03:48,666 --> 00:03:50,000 WILLERSLEV: You know what people mean 68 00:03:50,000 --> 00:03:51,766 when they say, mission impossible, right? 69 00:03:51,766 --> 00:03:54,800 They actually mean it might be possible. 70 00:03:54,800 --> 00:03:58,466 No one has ever succeeded in getting DNA 71 00:03:58,466 --> 00:04:00,700 older than one million years. 72 00:04:00,700 --> 00:04:03,766 But our tools are getting better. 73 00:04:03,766 --> 00:04:06,566 NARRATOR: And as the technology gets more powerful, 74 00:04:06,566 --> 00:04:10,833 these scientists are chasing a new discovery. 75 00:04:10,833 --> 00:04:13,366 To everyone's surprise, 76 00:04:13,366 --> 00:04:15,533 the secret to smashing the limit 77 00:04:15,533 --> 00:04:18,166 could be lying right beneath our feet. 78 00:04:18,166 --> 00:04:20,700 Now, we're on the verge of recovering 79 00:04:20,700 --> 00:04:24,833 genetic traces of a lost world from before the Ice Age. 80 00:04:24,833 --> 00:04:29,766 This ancient DNA, forged in a hotter climate, 81 00:04:29,766 --> 00:04:33,433 might even help us survive our own warming world. 82 00:04:34,833 --> 00:04:40,166 ♪ 83 00:04:46,666 --> 00:04:48,033 WILLERSLEV: When I was in school, 84 00:04:48,033 --> 00:04:50,400 if you had said to my teacher, 85 00:04:50,400 --> 00:04:52,733 "Someday, Eske will be a scientist," 86 00:04:52,733 --> 00:04:55,066 they would have laughed. 87 00:04:55,066 --> 00:04:57,733 I mean, I would have laughed too. 88 00:04:57,733 --> 00:04:59,900 I was a rebel, a troublemaker. 89 00:05:02,233 --> 00:05:04,933 I wasn't good at the typical things 90 00:05:04,933 --> 00:05:08,000 that people connect to being a scientist. 91 00:05:10,433 --> 00:05:14,300 I was a school failure. 92 00:05:14,300 --> 00:05:15,600 That's the truth. 93 00:05:15,600 --> 00:05:18,666 ♪ 94 00:05:18,666 --> 00:05:23,300 But I think I have one capability 95 00:05:23,300 --> 00:05:26,766 which has proven super valuable: 96 00:05:26,766 --> 00:05:30,133 I have a very good imagination. 97 00:05:32,300 --> 00:05:34,166 ♪ 98 00:05:36,666 --> 00:05:38,100 I used to think I was born too late 99 00:05:39,666 --> 00:05:42,733 when I realized there's no frontiers left, 100 00:05:42,733 --> 00:05:45,766 everything is mapped. 101 00:05:45,766 --> 00:05:47,133 But there is a frontier. 102 00:05:49,100 --> 00:05:52,600 Our frontier is the deep past. 103 00:05:52,600 --> 00:05:55,833 That is where we can still be explorers. 104 00:06:06,000 --> 00:06:07,500 NARRATOR: In Iceland, Eske Willerslev's team 105 00:06:07,500 --> 00:06:11,333 is pulling mud from the bottom of frozen lakes, 106 00:06:11,333 --> 00:06:16,433 mud laced with DNA from a long-gone world. 107 00:06:18,200 --> 00:06:19,466 (machinery whirring) 108 00:06:20,733 --> 00:06:24,400 ♪ 109 00:06:27,466 --> 00:06:30,033 WILLERSLEV: DNA is a, a blueprint, right? 110 00:06:30,033 --> 00:06:32,533 It's the code who makes you who you are. 111 00:06:34,833 --> 00:06:37,700 Different individuals have different DNA codes. 112 00:06:37,700 --> 00:06:40,666 Different species have different DNA codes. 113 00:06:40,666 --> 00:06:45,300 So, it means if you can pull out a piece of the DNA code, 114 00:06:45,300 --> 00:06:48,466 you can actually map it to all known DNA codes, 115 00:06:48,466 --> 00:06:51,100 all known blueprints. 116 00:06:51,100 --> 00:06:53,366 And then you can identify, well, 117 00:06:53,366 --> 00:06:55,900 what organism are we talking about here? 118 00:06:57,200 --> 00:07:00,733 NARRATOR: On this expedition, Eske's team is hunting for DNA 119 00:07:00,733 --> 00:07:02,733 from before the Vikings settled Iceland, 120 00:07:02,733 --> 00:07:04,566 about 1,200 years ago. 121 00:07:04,566 --> 00:07:07,133 ♪ 122 00:07:07,133 --> 00:07:10,100 WILLERSLEV: 1,200 years is nothing in ancient DNA research, 123 00:07:10,100 --> 00:07:13,633 especially in the Arctic where it's cold. 124 00:07:13,633 --> 00:07:17,066 Still, at a certain point, DNA becomes too difficult to read. 125 00:07:17,066 --> 00:07:19,133 So, there is a limit. 126 00:07:19,133 --> 00:07:21,600 ♪ 127 00:07:21,600 --> 00:07:23,400 And I would say, 128 00:07:23,400 --> 00:07:25,033 I've always been obsessed with this limit, 129 00:07:25,033 --> 00:07:27,300 to push this limit. 130 00:07:27,300 --> 00:07:29,666 How far can we go? 131 00:07:29,666 --> 00:07:32,366 I still haven't got an answer to that question. 132 00:07:33,900 --> 00:07:37,233 But I'm sure it's further than what we think. 133 00:07:38,566 --> 00:07:41,133 NARRATOR: So, what is the limit? 134 00:07:41,133 --> 00:07:42,433 Back in the '90s, 135 00:07:42,433 --> 00:07:45,233 some scientists got a little carried away. 136 00:07:46,233 --> 00:07:47,366 SHAPIRO: "Jurassic Park" 137 00:07:47,366 --> 00:07:48,900 was not a documentary. 138 00:07:48,900 --> 00:07:50,866 ♪ 139 00:07:52,366 --> 00:07:54,933 The early days of ancient DNA were a bit of a disaster. 140 00:07:54,933 --> 00:07:57,933 Unless you were in PR, in which case, it was fantastic. 141 00:07:59,366 --> 00:08:02,466 There was a whole bunch of what we now know 142 00:08:02,466 --> 00:08:06,966 is complete nonsense that was published with just abandon, 143 00:08:06,966 --> 00:08:11,200 just excitement and enthusiasm rather than actual science. 144 00:08:11,200 --> 00:08:14,100 I mean, everybody wants there to be dinosaur DNA. 145 00:08:14,100 --> 00:08:16,433 And so, somebody who says, "Hey, 146 00:08:16,433 --> 00:08:17,800 "I got this really well-preserved dinosaur. 147 00:08:17,800 --> 00:08:19,333 And guess what? There's DNA in it!" 148 00:08:19,333 --> 00:08:22,866 Of course the media are gonna be super excited about this! 149 00:08:22,866 --> 00:08:27,233 ♪ 150 00:08:27,233 --> 00:08:29,266 NARRATOR: And Hollywood couldn't resist. 151 00:08:29,266 --> 00:08:31,966 (fans cheering) 152 00:08:31,966 --> 00:08:34,933 (cameras clicking) 153 00:08:34,933 --> 00:08:37,566 SHAPIRO: So let's reconstruct "Jurassic Park." 154 00:08:37,566 --> 00:08:39,700 Scientists go somewhere hot, 155 00:08:39,700 --> 00:08:41,833 because amber forms in hot places, 156 00:08:41,833 --> 00:08:44,366 and they find a really beautiful piece of amber, 157 00:08:44,366 --> 00:08:48,300 inside of which they can see this fantastic insect 158 00:08:48,300 --> 00:08:50,200 that looks perfectly preserved. 159 00:08:50,200 --> 00:08:53,266 They take a big needle, and they stick it into the insect, 160 00:08:53,266 --> 00:08:58,066 and they draw out blood, presumably from a dinosaur. 161 00:08:58,066 --> 00:09:00,466 And then they take that blood to the lab, 162 00:09:00,466 --> 00:09:03,366 and they do some magic 163 00:09:03,366 --> 00:09:05,266 that for some reason involves frogs, 164 00:09:05,266 --> 00:09:07,100 even though we already knew at the time 165 00:09:07,100 --> 00:09:09,966 that birds were the closest living ancestor of dinosaurs. 166 00:09:09,966 --> 00:09:13,166 And then more magic happens and, uh, 167 00:09:13,166 --> 00:09:15,433 dinosaurs are back to life! 168 00:09:15,433 --> 00:09:18,766 But we now know a lot more about DNA than we used to. 169 00:09:18,766 --> 00:09:22,000 And everything we know tells us, no question about it, 170 00:09:22,000 --> 00:09:24,633 that this molecule just doesn't stick around 171 00:09:24,633 --> 00:09:27,433 for millions and millions of years. 172 00:09:27,433 --> 00:09:31,700 Dinosaurs have been extinct for more than 65 million years. 173 00:09:31,700 --> 00:09:35,200 We will never get dinosaur DNA. 174 00:09:35,200 --> 00:09:38,700 "Jurassic Park" is not going to happen. 175 00:09:38,700 --> 00:09:40,300 I'm sorry. 176 00:09:41,733 --> 00:09:45,100 ♪ 177 00:09:45,100 --> 00:09:48,933 Getting DNA out of things that are alive is easy. 178 00:09:48,933 --> 00:09:52,000 This is because modern DNA, DNA from living organisms, 179 00:09:52,000 --> 00:09:54,100 is in fantastic condition. 180 00:09:54,100 --> 00:09:57,133 Long strands of DNA, if you can think of it 181 00:09:57,133 --> 00:09:59,133 kind of as party streamers. 182 00:09:59,133 --> 00:10:00,766 ♪ 183 00:10:00,766 --> 00:10:04,766 Ancient DNA is more like confetti. 184 00:10:04,766 --> 00:10:08,366 The reason that modern DNA party streamers get chopped up 185 00:10:08,366 --> 00:10:11,066 into the confetti that is ancient DNA 186 00:10:11,066 --> 00:10:16,633 is because of random processes that happen outside the body. 187 00:10:16,633 --> 00:10:19,900 Mostly things like UV radiation from the sun. 188 00:10:19,900 --> 00:10:23,033 When we walk outside, UV hits our skin 189 00:10:23,033 --> 00:10:26,300 and it gets into our cells, and it damages our DNA. 190 00:10:26,300 --> 00:10:29,466 But when we're alive, we have proofreading enzymes 191 00:10:29,466 --> 00:10:31,200 that will come along 192 00:10:31,200 --> 00:10:32,900 and fix those damages. 193 00:10:32,900 --> 00:10:34,366 Otherwise, we would get cancer 194 00:10:34,366 --> 00:10:35,633 every time we walked outside. 195 00:10:35,633 --> 00:10:38,066 But proofreading and fixing DNA, 196 00:10:38,066 --> 00:10:41,266 this is an energy-requiring process. 197 00:10:41,266 --> 00:10:44,033 And after you're dead, there is no more energy. 198 00:10:44,033 --> 00:10:48,866 ♪ 199 00:10:51,300 --> 00:10:52,700 RAGHAVAN: With ancient DNA, 200 00:10:52,700 --> 00:10:55,400 it's always been a needle in the haystack problem. 201 00:10:57,200 --> 00:10:59,766 This is a fragile molecule. 202 00:10:59,766 --> 00:11:01,700 So, even when we first understood 203 00:11:01,700 --> 00:11:04,000 that DNA could stick around after death, 204 00:11:04,000 --> 00:11:07,100 the question was, how much and where? 205 00:11:08,300 --> 00:11:10,100 Early on, we thought 206 00:11:10,100 --> 00:11:11,433 only in soft tissue-- 207 00:11:11,433 --> 00:11:14,466 so, a human mummy or a frozen mammoth. 208 00:11:16,000 --> 00:11:17,500 In about 1990, 209 00:11:17,500 --> 00:11:19,500 we had the huge insight that fossil bones 210 00:11:19,500 --> 00:11:21,500 and teeth could protect DNA like time capsules. 211 00:11:21,500 --> 00:11:24,800 But well-preserved fossils are rare. 212 00:11:24,800 --> 00:11:28,400 And fossils that contain DNA, they're even rarer. 213 00:11:28,400 --> 00:11:32,066 So, in our field, that has been one of the biggest challenges. 214 00:11:32,066 --> 00:11:35,833 We're all chasing these precious time capsules. 215 00:11:35,833 --> 00:11:38,600 ♪ 216 00:11:38,600 --> 00:11:41,233 NARRATOR: Three decades ago, 217 00:11:41,233 --> 00:11:44,100 Eske was determined to join the hunt. 218 00:11:44,100 --> 00:11:46,100 But the odds were against him. 219 00:11:49,566 --> 00:11:52,266 WILLERSLEV: In 1995, I was a biology student 220 00:11:52,266 --> 00:11:54,066 and I wanted to do 221 00:11:54,066 --> 00:11:56,633 my research on ancient DNA. 222 00:11:56,633 --> 00:11:58,566 But I had no fossils. 223 00:11:58,566 --> 00:12:03,066 I wasn't famous, so nobody wanted to give me fossils. 224 00:12:03,066 --> 00:12:05,533 That was a bit of a problem. 225 00:12:05,533 --> 00:12:08,300 You want to do ancient DNA, but you have no fossils. 226 00:12:10,800 --> 00:12:14,800 I remember I was in my flat, 227 00:12:14,800 --> 00:12:16,566 it was an awful day. 228 00:12:16,566 --> 00:12:19,700 (thunder rumbling) The rain was just coming down, 229 00:12:19,700 --> 00:12:22,366 and leaves were falling from the trees. 230 00:12:22,366 --> 00:12:26,633 And I saw this woman out walking her dog. 231 00:12:26,633 --> 00:12:28,566 And she stops. 232 00:12:28,566 --> 00:12:32,766 The dog squats, takes a poop. 233 00:12:34,233 --> 00:12:35,733 It's funny, 234 00:12:35,733 --> 00:12:38,966 inspiration sometimes comes out of the strangest times. 235 00:12:38,966 --> 00:12:40,233 (chuckles) 236 00:12:40,233 --> 00:12:44,133 I'm looking at that miserable wet dog, 237 00:12:44,133 --> 00:12:47,266 thinking, "Well, there's DNA in the dog. 238 00:12:47,266 --> 00:12:50,833 "So, there's DNA in the dog poop, right? 239 00:12:50,833 --> 00:12:53,866 But will it survive?" 240 00:12:53,866 --> 00:12:55,766 We know there's DNA in the leaves, 241 00:12:55,766 --> 00:12:59,700 but we also do know that these things will disappear. 242 00:12:59,700 --> 00:13:03,366 After next rainfall, the dog poop will disappear. 243 00:13:03,366 --> 00:13:05,766 After a few years, the leaves will be gone. 244 00:13:05,766 --> 00:13:10,566 The question I asked myself was, "What will happen to the DNA? 245 00:13:10,566 --> 00:13:15,533 Will that be gone, too? Or will that be preserved in the soil?" 246 00:13:15,533 --> 00:13:18,166 Because if it's preserved in the soil, 247 00:13:18,166 --> 00:13:22,400 we don't need any fossils, problem solved. 248 00:13:23,733 --> 00:13:26,866 So, I remember I went into the coffee room 249 00:13:26,866 --> 00:13:29,266 in the Department of Zoology, 250 00:13:29,266 --> 00:13:31,333 where all the professors were sitting, 251 00:13:31,333 --> 00:13:33,200 you know, having their lunch. 252 00:13:33,200 --> 00:13:35,200 And I came with this idea saying, "Well, what about 253 00:13:35,200 --> 00:13:38,633 looking in, in the soil for DNA of animals and plants?" 254 00:13:38,633 --> 00:13:40,566 (laughter) And they were laughing. 255 00:13:40,566 --> 00:13:43,200 And my, my supervisor turned around, 256 00:13:43,200 --> 00:13:44,466 he was head of department, saying, 257 00:13:44,466 --> 00:13:49,233 (speaking Danish) 258 00:13:49,233 --> 00:13:50,566 (laughter) 259 00:13:50,566 --> 00:13:53,433 "I never heard anything as stupid in my life." 260 00:13:54,966 --> 00:13:57,900 No one had ever thought to recover DNA from dirt. 261 00:13:57,900 --> 00:13:59,666 And why would it be there? 262 00:13:59,666 --> 00:14:01,800 The idea is that DNA is, is kind of known to be 263 00:14:01,800 --> 00:14:04,066 such an unstable molecule in general. 264 00:14:04,066 --> 00:14:05,800 If you're working in a molecular biology lab 265 00:14:05,800 --> 00:14:07,600 and you don't look after your DNA, it's gone very fast. 266 00:14:07,600 --> 00:14:10,433 So yeah, it was a completely crazy idea 267 00:14:10,433 --> 00:14:12,166 that, that it would even be found. 268 00:14:12,166 --> 00:14:15,066 I mean, that DNA enters the environment is obvious 269 00:14:15,066 --> 00:14:17,100 if an animal urinates or defecates. 270 00:14:17,100 --> 00:14:20,466 But that DNA stays in the environment, completely crazy. 271 00:14:22,033 --> 00:14:24,133 SHAPIRO: So, early on, we didn't know 272 00:14:24,133 --> 00:14:26,133 how long ancient DNA could survive. 273 00:14:26,133 --> 00:14:28,233 But there was a second really big hole 274 00:14:28,233 --> 00:14:30,600 in our understanding: contamination. 275 00:14:30,600 --> 00:14:32,500 ♪ 276 00:14:32,500 --> 00:14:36,266 Ancient DNA getting mixed up with modern DNA. 277 00:14:37,966 --> 00:14:40,666 Well, the trouble is that DNA is everywhere. 278 00:14:40,666 --> 00:14:43,866 My DNA is now on this chair and on my hands 279 00:14:43,866 --> 00:14:45,633 and on my shirt, 280 00:14:45,633 --> 00:14:48,833 and DNA is coming out of my mouth as I talk. 281 00:14:48,833 --> 00:14:53,600 And there is microbial DNA absolutely everywhere. 282 00:14:53,600 --> 00:14:56,633 So, when people were sequencing these bones, 283 00:14:56,633 --> 00:14:58,666 they were getting DNA. 284 00:14:58,666 --> 00:15:01,300 And they were saying, "Wow, there's DNA in these bones. 285 00:15:01,300 --> 00:15:03,100 It must be dinosaur DNA." 286 00:15:03,100 --> 00:15:05,500 I think there was some dinosaur DNA 287 00:15:05,500 --> 00:15:07,700 that was published that they were really excited about 288 00:15:07,700 --> 00:15:09,900 because it closely matched a bird. 289 00:15:09,900 --> 00:15:12,633 Well, turns out the field excavation team 290 00:15:12,633 --> 00:15:14,266 was having a chicken dinner one night. 291 00:15:14,266 --> 00:15:15,666 (chicken clucking) 292 00:15:15,666 --> 00:15:17,366 (typing) 293 00:15:17,366 --> 00:15:20,866 WILLERSLEV: In those early days, when I was still a student, 294 00:15:20,866 --> 00:15:25,500 we were all struggling with the problem of contamination. 295 00:15:25,500 --> 00:15:27,733 Which was the big downfall 296 00:15:27,733 --> 00:15:30,566 of the dinosaur DNA guys of the '90s. 297 00:15:30,566 --> 00:15:32,533 And I decided, well, 298 00:15:32,533 --> 00:15:35,566 somehow, we are going to solve that problem. 299 00:15:35,566 --> 00:15:39,000 I was working on this with another student, 300 00:15:39,000 --> 00:15:41,100 Anders Hansen. 301 00:15:41,100 --> 00:15:46,566 So, we had this room that were basically our clean laboratory. 302 00:15:46,566 --> 00:15:50,033 But we had a problem with a mold contamination. 303 00:15:52,233 --> 00:15:54,700 And in the end, we became so desperate, 304 00:15:54,700 --> 00:15:57,866 we decided, okay, we will basically clean 305 00:15:57,866 --> 00:16:02,166 the entire room down with very strong bleach. 306 00:16:02,166 --> 00:16:05,300 ♪ 307 00:16:05,300 --> 00:16:07,066 We knew, well, it wasn't really allowed, 308 00:16:07,066 --> 00:16:08,833 and we didn't have money for gas masks. 309 00:16:08,833 --> 00:16:11,066 (scrubbing) 310 00:16:11,066 --> 00:16:13,333 ♪ 311 00:16:13,333 --> 00:16:16,266 Anders got, got dizzy and threw up. 312 00:16:16,266 --> 00:16:18,266 (retching) 313 00:16:20,600 --> 00:16:22,666 And the security guard was coming, 314 00:16:22,666 --> 00:16:26,000 saying, "What the (bleep) is going on here?" 315 00:16:26,000 --> 00:16:29,833 It's smelling like a swimming pool in the entire building." 316 00:16:29,833 --> 00:16:34,100 And Monday morning, we were, had to stand in front 317 00:16:34,100 --> 00:16:36,266 of the professor and the lab director. 318 00:16:36,266 --> 00:16:37,833 And they were furious, right? 319 00:16:37,833 --> 00:16:39,300 I mean, "What are you guys doing? 320 00:16:39,300 --> 00:16:41,900 I mean, do you know this is totally illegal?" 321 00:16:41,900 --> 00:16:43,366 ♪ 322 00:16:43,366 --> 00:16:46,900 But the good news was even though we, we got all this heat, 323 00:16:46,900 --> 00:16:49,833 the fungi contamination were gone! 324 00:16:51,200 --> 00:16:54,666 NARRATOR: Finally, Eske had a mold-free lab. 325 00:16:54,666 --> 00:16:59,100 He first tried getting DNA out of 2,000-year-old ice. 326 00:16:59,100 --> 00:17:01,333 WILLERSLEV: We got ice cores from Greenland, 327 00:17:01,333 --> 00:17:04,433 and we showed we could recover ancient fungi DNA 328 00:17:04,433 --> 00:17:08,266 trapped in the ice without contamination. 329 00:17:08,266 --> 00:17:10,733 And that was big. 330 00:17:10,733 --> 00:17:14,133 So, then we knew, we were ready to move 331 00:17:14,133 --> 00:17:19,100 to the next step-- searching for DNA in the dirt. 332 00:17:20,700 --> 00:17:23,900 So, I really believed in this idea 333 00:17:23,900 --> 00:17:26,700 of environmental DNA or dirt DNA. 334 00:17:26,700 --> 00:17:28,833 And more than that, 335 00:17:28,833 --> 00:17:33,133 that it could survive in the environment as ancient DNA. 336 00:17:33,133 --> 00:17:34,333 But I had to prove it. 337 00:17:35,666 --> 00:17:41,300 So, I set out to retrieve ancient DNA from the dirt. 338 00:17:41,300 --> 00:17:43,300 And at that point, no one had done that. 339 00:17:44,400 --> 00:17:46,066 NARRATOR: Eske was searching for DNA 340 00:17:46,066 --> 00:17:50,733 from the Ice Age, which ended 12,000 years ago. 341 00:17:50,733 --> 00:17:53,833 It kept our planet in a frigid grip 342 00:17:53,833 --> 00:17:57,433 for about two-and-a-half million years. 343 00:17:57,433 --> 00:18:01,000 WILLERSLEV: The Ice Age, it's an amazing period. 344 00:18:01,000 --> 00:18:04,133 It's the time of the big mammals. 345 00:18:04,133 --> 00:18:07,200 You have giant wolves, giant beavers, 346 00:18:07,200 --> 00:18:10,366 mammoth, mastodons, right? 347 00:18:10,366 --> 00:18:13,000 (animals growling) 348 00:18:13,000 --> 00:18:15,166 So, I thought, 349 00:18:15,166 --> 00:18:18,100 imagine how much poop and urine 350 00:18:18,100 --> 00:18:21,766 these big mammals had been producing over time, right? 351 00:18:21,766 --> 00:18:25,166 That is in the soil, in the surrounding, 352 00:18:25,166 --> 00:18:27,833 frozen in time in the arctic. 353 00:18:29,933 --> 00:18:31,466 So, my idea was to bring back 354 00:18:31,466 --> 00:18:35,200 that Ice Age world by retrieving DNA 355 00:18:35,200 --> 00:18:37,100 directly from the permafrost. 356 00:18:37,100 --> 00:18:39,733 And that permafrost I got from Siberia. 357 00:18:41,300 --> 00:18:43,733 (drilling) 358 00:18:43,733 --> 00:18:46,266 So, while everyone else 359 00:18:46,266 --> 00:18:48,933 was looking for DNA in fossil bone and teeth, 360 00:18:48,933 --> 00:18:52,466 and discovering one species at a time, 361 00:18:52,466 --> 00:18:56,066 I was looking in the dirt for everything. 362 00:18:56,066 --> 00:18:59,000 ♪ 363 00:18:59,000 --> 00:19:02,366 NARRATOR: It's one thing to recover ancient DNA, 364 00:19:02,366 --> 00:19:04,966 but it's a far more daunting challenge 365 00:19:04,966 --> 00:19:09,500 to read those tiny fragments of genetic confetti. 366 00:19:09,500 --> 00:19:13,466 That is, to decode what kind of ancient life they come from. 367 00:19:13,466 --> 00:19:15,266 The shorter the fragment, 368 00:19:15,266 --> 00:19:18,966 the harder it is to identify. 369 00:19:18,966 --> 00:19:21,566 A genome is like a twisted ladder. 370 00:19:21,566 --> 00:19:23,800 So, if you think of a long ladder, 371 00:19:23,800 --> 00:19:26,200 every rung is a base pair. 372 00:19:27,700 --> 00:19:32,766 And a base is a single molecule-- A, T, G and C. 373 00:19:34,400 --> 00:19:37,566 A human genome is incredibly long. 374 00:19:37,566 --> 00:19:40,233 It has three billion base pairs. 375 00:19:40,233 --> 00:19:43,133 So, that's three billion rungs on the ladder. 376 00:19:43,133 --> 00:19:45,533 That's a big number. 377 00:19:45,533 --> 00:19:48,266 But when we're working with ancient DNA, 378 00:19:48,266 --> 00:19:50,333 we're working with short pieces, 379 00:19:50,333 --> 00:19:53,366 pieces just a few rungs long. 380 00:19:53,366 --> 00:19:57,133 And we have to hope that those little pieces 381 00:19:57,133 --> 00:19:59,766 contain enough unique information 382 00:19:59,766 --> 00:20:02,200 that we can match them to known DNA. 383 00:20:03,966 --> 00:20:06,433 NARRATOR: Some of Eske's Siberian permafrost 384 00:20:06,433 --> 00:20:09,100 was 400,000 years old. 385 00:20:09,100 --> 00:20:11,200 If he could identify species 386 00:20:11,200 --> 00:20:15,833 from ancient DNA frozen inside it, he would set a new record. 387 00:20:15,833 --> 00:20:18,400 ♪ 388 00:20:18,400 --> 00:20:21,833 WILLERSLEV: So, it's Christmas Eve, and I'm, I'm sitting 389 00:20:21,833 --> 00:20:23,433 alone in the lab, 390 00:20:23,433 --> 00:20:26,366 everybody have already gone home, right, for, for Christmas. 391 00:20:26,366 --> 00:20:31,666 And I'm, I'm basically checking the DNA sequences 392 00:20:31,666 --> 00:20:34,866 that we got out of the dirt and comparing those 393 00:20:34,866 --> 00:20:37,700 to all known DNA sequences in the world. 394 00:20:37,700 --> 00:20:39,333 And when I see the results, 395 00:20:39,333 --> 00:20:44,433 the hairs on my back are just rising. 396 00:20:44,433 --> 00:20:46,400 It was-- bang!-- woolly mammoth. 397 00:20:46,400 --> 00:20:48,000 It was-- bang!-- bison. 398 00:20:48,000 --> 00:20:51,833 It was-- bang!-- reindeer. It was-- bang!-- hare. 399 00:20:51,833 --> 00:20:54,966 It was-- bang, bang, bang!-- 400 00:20:54,966 --> 00:20:57,900 different types of plants. 401 00:20:59,200 --> 00:21:03,100 It worked better than I could even have imagined. 402 00:21:04,600 --> 00:21:08,200 NARRATOR: Eske had matched the ancient DNA in his Siberian dirt 403 00:21:08,200 --> 00:21:11,566 to known species, whose genetic sequences 404 00:21:11,566 --> 00:21:14,266 were collected in a vast catalogue. 405 00:21:14,266 --> 00:21:17,966 And sure enough, he found dozens of matches, 406 00:21:17,966 --> 00:21:20,500 including extinct species. 407 00:21:20,500 --> 00:21:22,566 Eske was the first to show 408 00:21:22,566 --> 00:21:25,766 that enough DNA can survive in the dirt 409 00:21:25,766 --> 00:21:28,866 to paint a picture of the past. 410 00:21:30,200 --> 00:21:31,933 Still a student, 411 00:21:31,933 --> 00:21:34,733 he'd just sparked a new field of science-- 412 00:21:34,733 --> 00:21:37,900 ancient environmental DNA. 413 00:21:37,900 --> 00:21:39,966 The reason the technique of environmental DNA works 414 00:21:39,966 --> 00:21:42,433 is that DNA is everywhere. 415 00:21:42,433 --> 00:21:44,933 It is raining DNA. 416 00:21:44,933 --> 00:21:48,666 The very problem we had with DNA contaminating samples-- 417 00:21:48,666 --> 00:21:51,700 that DNA is falling off of me and coming out of my mouth 418 00:21:51,700 --> 00:21:53,733 and floating in the air around me-- 419 00:21:53,733 --> 00:21:57,366 that is exactly the opportunity we have with environmental DNA. 420 00:21:57,366 --> 00:21:59,833 So I realized it's not the scarcity 421 00:21:59,833 --> 00:22:01,933 of DNA that is limiting us. 422 00:22:01,933 --> 00:22:06,900 Environmental DNA is everywhere; the limit is time. 423 00:22:06,900 --> 00:22:09,766 And this is really when I started thinking, 424 00:22:09,766 --> 00:22:14,100 "Well, how far back in time can we really push this?" 425 00:22:14,100 --> 00:22:18,466 ♪ 426 00:22:26,066 --> 00:22:28,100 SHAPIRO: So today we are in the Holocene. 427 00:22:29,733 --> 00:22:32,833 That's about the last 12,000 years. 428 00:22:32,833 --> 00:22:34,966 ♪ 429 00:22:34,966 --> 00:22:37,333 Before that, it was the Pleistocene, 430 00:22:37,333 --> 00:22:40,100 a period of lots of ice ages, more than 20, 431 00:22:40,100 --> 00:22:44,166 lasted about two-and-a-half million years. 432 00:22:44,166 --> 00:22:46,466 And before that was the Pliocene, 433 00:22:46,466 --> 00:22:48,966 when it was much warmer than the Pleistocene. 434 00:22:48,966 --> 00:22:51,366 (horse neighs, camel grunts) 435 00:22:51,366 --> 00:22:53,433 Yeah, it was a really weird place, 436 00:22:53,433 --> 00:22:55,066 you would not recognize that world. 437 00:22:58,166 --> 00:22:59,800 When you go back three million years, 438 00:22:59,800 --> 00:23:01,300 you're in a way warmer climate. 439 00:23:01,300 --> 00:23:03,466 Earth was just hotter. 440 00:23:03,466 --> 00:23:07,033 (insects buzzing) 441 00:23:07,033 --> 00:23:08,966 And it had been that way for a very long time, 442 00:23:08,966 --> 00:23:10,800 since before the extinction 443 00:23:10,800 --> 00:23:13,033 of the dinosaurs 65 million years ago. 444 00:23:14,300 --> 00:23:16,733 (birds calling) 445 00:23:16,733 --> 00:23:18,466 I'm a vertebrate paleontologist. 446 00:23:18,466 --> 00:23:20,200 I study the animals that lived 447 00:23:20,200 --> 00:23:22,233 in the Arctic before the Ice Age. 448 00:23:22,233 --> 00:23:24,233 Mammals of the Pliocene Arctic. 449 00:23:25,233 --> 00:23:28,133 The reality is we don't know very much. 450 00:23:28,133 --> 00:23:30,533 The time before the Ice Age began, the Pliocene, 451 00:23:30,533 --> 00:23:32,566 it's kind of a lost world. 452 00:23:34,366 --> 00:23:37,833 We don't have full skeletons of any Pliocene mammals. 453 00:23:39,400 --> 00:23:41,000 We just have fragments, shards of bone, 454 00:23:41,000 --> 00:23:44,133 evidence of maybe 13 species. 455 00:23:44,133 --> 00:23:47,500 ♪ 456 00:23:47,500 --> 00:23:48,633 I still have so many questions. 457 00:23:52,200 --> 00:23:54,833 For a paleontologist like me, it's really frustrating. 458 00:23:56,000 --> 00:24:00,700 NARRATOR: So, where fossils are lacking, could DNA help us? 459 00:24:00,700 --> 00:24:02,466 Could genetic traces 460 00:24:02,466 --> 00:24:05,400 really endure for millions of years? 461 00:24:05,400 --> 00:24:11,400 Everything we knew about DNA had told us that was impossible. 462 00:24:11,400 --> 00:24:15,266 WILLERSLEV: The oldest DNA is the coldest DNA. 463 00:24:17,233 --> 00:24:19,600 DNA is fragile, 464 00:24:19,600 --> 00:24:21,833 so it falls apart over time, 465 00:24:21,833 --> 00:24:24,633 but cold slows that process down. 466 00:24:24,633 --> 00:24:29,000 ♪ 467 00:24:29,000 --> 00:24:31,333 No one has ever succeeded 468 00:24:31,333 --> 00:24:34,266 in getting DNA older than one million years. 469 00:24:36,366 --> 00:24:39,933 But our tools are getting better. 470 00:24:39,933 --> 00:24:42,566 So I think the limits might change. 471 00:24:44,233 --> 00:24:48,400 NARRATOR: Twenty years ago, recovering 400,000-year-old DNA 472 00:24:48,400 --> 00:24:53,033 from Siberian permafrost was an impressive leap back in time. 473 00:24:54,933 --> 00:24:57,600 The student was suddenly a professor-- 474 00:24:57,600 --> 00:24:59,566 the youngest in Denmark. 475 00:25:00,633 --> 00:25:04,100 But Eske's quest had just begun. 476 00:25:05,833 --> 00:25:07,166 WILLERSLEV: So, I just happened to get 477 00:25:07,166 --> 00:25:10,000 this invitation from a group of geologists 478 00:25:10,000 --> 00:25:13,566 to go up to northeastern Greenland. 479 00:25:13,566 --> 00:25:16,700 And this is a remarkable place. 480 00:25:16,700 --> 00:25:18,866 I mean, there you have, uh, something called 481 00:25:18,866 --> 00:25:21,066 the Kap Kobenhavn Formation. 482 00:25:21,066 --> 00:25:25,233 And it's a super dry and a super cold place. 483 00:25:25,233 --> 00:25:26,666 Naturally, 484 00:25:26,666 --> 00:25:30,600 I thought, northern Greenland would hold the answer. 485 00:25:32,400 --> 00:25:37,466 If really old DNA is going to be preserved anywhere, it's here. 486 00:25:38,933 --> 00:25:42,600 ♪ 487 00:25:42,600 --> 00:25:44,100 Northeastern Greenland-- 488 00:25:44,100 --> 00:25:49,500 it's one of the most hostile places on Earth, extremely cold. 489 00:25:49,500 --> 00:25:54,300 But even more important, this is an Arctic desert. 490 00:25:56,700 --> 00:26:00,233 It was too dry for glaciers to form. 491 00:26:00,233 --> 00:26:03,900 No glaciers to grind away the landscape. 492 00:26:03,900 --> 00:26:08,866 The sediments up there are perfectly preserved. 493 00:26:08,866 --> 00:26:10,766 In Kap Kobenhavn, 494 00:26:10,766 --> 00:26:13,566 you're literally walking on dirt 495 00:26:13,566 --> 00:26:15,266 from before the Ice Age. 496 00:26:16,466 --> 00:26:17,866 It's incredible. 497 00:26:17,866 --> 00:26:21,600 This place that is almost barren ground today, right, 498 00:26:21,600 --> 00:26:26,400 in the sediments, we discovered chunks of trees of wood 499 00:26:26,400 --> 00:26:29,433 that are three million years old 500 00:26:29,433 --> 00:26:31,400 but is still preserved there. 501 00:26:31,400 --> 00:26:33,033 I mean, you can basically 502 00:26:33,033 --> 00:26:36,166 take them up and use them as fuel in your campfire. 503 00:26:37,400 --> 00:26:39,566 So this told me two things. 504 00:26:39,566 --> 00:26:41,100 First, Kap Kobenhavn 505 00:26:41,100 --> 00:26:43,833 must have looked very different in the past. 506 00:26:43,833 --> 00:26:47,366 And secondly, this must be among 507 00:26:47,366 --> 00:26:51,200 the best places in the world for long-term preservation of DNA. 508 00:26:51,200 --> 00:26:53,900 (waves lapping shore) 509 00:26:53,900 --> 00:26:56,700 This gave me an idea. 510 00:26:57,700 --> 00:26:59,566 A naughty idea. (laughs) 511 00:26:59,566 --> 00:27:04,966 ♪ 512 00:27:04,966 --> 00:27:08,233 What if we could just dig in the dirt 513 00:27:08,233 --> 00:27:10,500 and recover DNA millions of years old? 514 00:27:13,266 --> 00:27:14,433 SHAPIRO: If your goal is 515 00:27:14,433 --> 00:27:16,666 to get the oldest sample, 516 00:27:16,666 --> 00:27:20,666 then you go where that oldest sample is likely to be. 517 00:27:20,666 --> 00:27:23,333 It reckons back to the age of exploration, right? 518 00:27:23,333 --> 00:27:26,400 I mean, th... think about my, my kids are in fourth grade, 519 00:27:26,400 --> 00:27:27,666 uh, so they're learning about 520 00:27:27,666 --> 00:27:29,633 the explorers that went around the world. 521 00:27:29,633 --> 00:27:33,333 And this is kind of, I think, how Eske sees himself a bit. 522 00:27:33,333 --> 00:27:35,633 He's like, "Oh, you know what? There's an Arctic desert. 523 00:27:35,633 --> 00:27:38,200 I'm gonna go there, and I'm gonna get DNA from that." 524 00:27:38,200 --> 00:27:40,100 And he will because he's Eske. 525 00:27:40,100 --> 00:27:41,766 And that's how Eske works. 526 00:27:41,766 --> 00:27:42,900 (laughing) 527 00:27:42,900 --> 00:27:46,333 In 2005, I published this review paper 528 00:27:46,333 --> 00:27:49,300 where we basically claimed, well, 529 00:27:49,300 --> 00:27:53,233 ancient DNA cannot survive for more than one million years. 530 00:27:53,233 --> 00:27:55,500 That's the absolute limit. 531 00:27:55,500 --> 00:27:58,066 But in the back of my head, 532 00:27:58,066 --> 00:27:59,400 I was still wondering 533 00:27:59,400 --> 00:28:01,466 is that really true, right? 534 00:28:01,466 --> 00:28:05,400 Could DNA survive longer than one million years 535 00:28:05,400 --> 00:28:07,533 in a place like the Kap Kobenhavn Formation? 536 00:28:09,200 --> 00:28:11,866 So, on that same expedition, I thought, 537 00:28:11,866 --> 00:28:16,633 "Hey! I mean, we're here! Why not sample the sediments? 538 00:28:16,633 --> 00:28:20,933 You never know, we just might be able to find DNA." 539 00:28:20,933 --> 00:28:23,733 ♪ 540 00:28:23,733 --> 00:28:27,733 I remember it was pretty miserable up there. 541 00:28:27,733 --> 00:28:30,400 We were working in the freezing Arctic desert, 542 00:28:30,400 --> 00:28:33,533 where it rained anyway. 543 00:28:33,533 --> 00:28:35,800 Still, we cored into the frozen ground, 544 00:28:35,800 --> 00:28:38,500 and I got my crazy samples. 545 00:28:39,666 --> 00:28:42,033 (helicopter blades whirring) 546 00:28:42,033 --> 00:28:46,200 So, I took the sediment samples back to my lab in Copenhagen. 547 00:28:46,200 --> 00:28:49,133 And, uh, to be honest, 548 00:28:49,133 --> 00:28:53,033 this was the beginning of a very frustrating project. 549 00:28:54,833 --> 00:28:58,300 NARRATOR: Those Greenland samples would tease 550 00:28:58,300 --> 00:29:00,933 and torment Eske and his team 551 00:29:00,933 --> 00:29:04,400 for the next 15 years. 552 00:29:06,233 --> 00:29:09,900 In the early days, Astrid Schmidt was a doctoral student 553 00:29:09,900 --> 00:29:12,133 in Eske's lab. 554 00:29:12,133 --> 00:29:14,866 When Eske offered her the Greenland samples, 555 00:29:14,866 --> 00:29:17,166 she jumped on them. 556 00:29:17,166 --> 00:29:18,466 ASTRID SCHMIDT: At that time, 557 00:29:18,466 --> 00:29:20,533 Eske was a, a star in the scientific community, 558 00:29:20,533 --> 00:29:24,133 and I was inspired by Eske's enthusiasm. 559 00:29:26,700 --> 00:29:30,366 We had a hypothesis that, if the environment had been kept cold, 560 00:29:30,366 --> 00:29:33,433 and the temperatures had not been moving up and down, 561 00:29:33,433 --> 00:29:35,700 fluctuated, then we would have had 562 00:29:35,700 --> 00:29:37,633 at least a possibility of finding 563 00:29:37,633 --> 00:29:41,033 ancient DNA. 564 00:29:41,033 --> 00:29:42,966 So, we were, uh, being optimistic, 565 00:29:42,966 --> 00:29:46,433 knowing it was a long shot, but also knowing that we could get 566 00:29:46,433 --> 00:29:48,466 ground-breaking results from this. 567 00:29:50,000 --> 00:29:52,700 And there was DNA in the samples. 568 00:29:52,700 --> 00:29:53,766 We could see it. 569 00:29:53,766 --> 00:29:55,800 But it was super degraded. 570 00:29:55,800 --> 00:29:57,066 ♪ 571 00:29:57,066 --> 00:29:58,300 RAGHAVAN: It's not enough 572 00:29:58,300 --> 00:30:01,033 to see that your samples contain ancient DNA. 573 00:30:01,033 --> 00:30:03,766 You have to be able to identify that DNA 574 00:30:03,766 --> 00:30:06,600 and to know what forms of life it came from. 575 00:30:06,600 --> 00:30:09,966 To do that, the fragments need to be long enough. 576 00:30:09,966 --> 00:30:13,233 You need a certain number of base pairs in a fragment. 577 00:30:13,233 --> 00:30:15,300 You need enough rungs on your ladder. 578 00:30:16,666 --> 00:30:18,200 NARRATOR: When Astrid started, 579 00:30:18,200 --> 00:30:21,866 scientists needed at least 100 base pairs. 580 00:30:23,333 --> 00:30:24,800 SCHMIDT: We did everything we could 581 00:30:24,800 --> 00:30:26,400 with the technology that existed, 582 00:30:26,400 --> 00:30:29,700 but we just couldn't overcome the central problem. 583 00:30:29,700 --> 00:30:32,166 The Greenland DNA was just too old, 584 00:30:32,166 --> 00:30:35,433 the fragments were too short. 585 00:30:35,433 --> 00:30:37,100 It was very frustrating. 586 00:30:37,100 --> 00:30:41,100 The DNA, after one million year, was just total garbage. 587 00:30:41,100 --> 00:30:45,266 With, you can say, the technology in hand at the time, 588 00:30:45,266 --> 00:30:47,700 uh, the DNA was completely unreadable. 589 00:30:47,700 --> 00:30:49,566 Well, Astrid, uh, 590 00:30:49,566 --> 00:30:54,800 was one of many people in my lab 591 00:30:54,800 --> 00:30:58,866 that tried the Kap Kobenhavn samples and basically failed. 592 00:30:58,866 --> 00:31:01,600 In retrospect... 593 00:31:01,600 --> 00:31:03,366 (clicks tongue) I was probably not 594 00:31:03,366 --> 00:31:05,166 a very good supervisor, right? 595 00:31:05,166 --> 00:31:10,066 Because I, I kind of pushed for people to do these samples 596 00:31:10,066 --> 00:31:13,966 every time we had improvements of our methodology, 597 00:31:13,966 --> 00:31:17,033 in a hope, "Well, this time, they will work." 598 00:31:17,033 --> 00:31:20,966 If that happened, it would be a career booster. 599 00:31:20,966 --> 00:31:23,000 But the... 600 00:31:23,000 --> 00:31:27,700 the risk associated with this project was huge, right? 601 00:31:27,700 --> 00:31:30,633 So it was failure after failure. 602 00:31:30,633 --> 00:31:36,033 Kap Kobenhavn project was, um, yeah, a bit sensitive. 603 00:31:36,033 --> 00:31:38,400 As a postdoc, if you decided to invest 604 00:31:38,400 --> 00:31:41,666 your time in this, it was the case of 605 00:31:41,666 --> 00:31:43,700 having only so many years 606 00:31:43,700 --> 00:31:46,700 to be able to produce excellent research. 607 00:31:46,700 --> 00:31:48,666 If you're not able to produce research 608 00:31:48,666 --> 00:31:50,600 because the technology doesn't allow it, 609 00:31:50,600 --> 00:31:52,866 not because you're a bad researcher, 610 00:31:52,866 --> 00:31:55,666 you still end up with nothing to show for it. 611 00:31:56,666 --> 00:31:59,266 SCHMIDT: In 2013, I left research science, 612 00:31:59,266 --> 00:32:03,166 and I didn't pursue science, um, since then. 613 00:32:03,166 --> 00:32:06,233 I took a big risk, and I paid a price. 614 00:32:08,166 --> 00:32:10,266 (student speaking indistinctly) 615 00:32:10,266 --> 00:32:13,000 WILLERSLEV: Yeah, but again... the thing is, just like with... 616 00:32:13,000 --> 00:32:15,200 NARRATOR: In Eske's lab, students began calling 617 00:32:15,200 --> 00:32:16,900 the Greenland samples cursed. 618 00:32:16,900 --> 00:32:18,500 (Willerslev speaking indistinctly) 619 00:32:18,500 --> 00:32:22,600 But Eske and his team kept returning to Greenland, 620 00:32:22,600 --> 00:32:26,900 hoping to find DNA in better condition. 621 00:32:26,900 --> 00:32:30,933 Meanwhile, four more students suffered under the curse, 622 00:32:30,933 --> 00:32:35,400 failing to recover DNA long enough to identify. 623 00:32:35,400 --> 00:32:38,200 They all changed careers. 624 00:32:39,433 --> 00:32:44,200 But as they left, new ones stepped into their shoes. 625 00:32:44,200 --> 00:32:45,766 MIKKEL PEDERSEN: So, you, you can imagine what I felt 626 00:32:45,766 --> 00:32:48,066 when this, these samples landed on my table. 627 00:32:50,700 --> 00:32:51,866 So, I was a PhD student 628 00:32:51,866 --> 00:32:54,166 in Eske Willerslev's lab. 629 00:32:54,166 --> 00:32:57,200 This was my last option, also, to succeed in a project 630 00:32:57,200 --> 00:32:59,233 that I was given as a PhD student. 631 00:32:59,233 --> 00:33:02,533 I was coming to... (laughs) 632 00:33:02,533 --> 00:33:07,233 the final tries of, of actually making this a success. 633 00:33:07,233 --> 00:33:09,566 Back in the day, we needed 634 00:33:09,566 --> 00:33:13,833 almost hundred base pair fragments to survive in a sample 635 00:33:13,833 --> 00:33:17,266 in order to retrieve any DNA whatsoever. 636 00:33:18,266 --> 00:33:20,300 But the technology was changing. 637 00:33:20,300 --> 00:33:24,600 And I had a student, Mikkel, who came to me with an idea. 638 00:33:24,600 --> 00:33:26,266 I was immediately excited. 639 00:33:26,266 --> 00:33:29,600 I thought, "Yes, this could work." 640 00:33:29,600 --> 00:33:32,166 Mikkel suggested we use 641 00:33:32,166 --> 00:33:36,933 a powerful technique called shotgun sequencing. 642 00:33:36,933 --> 00:33:39,966 Shotgun sequencing itself wasn't new, 643 00:33:39,966 --> 00:33:43,300 but no one had ever used it on dirt DNA. 644 00:33:43,300 --> 00:33:45,600 I don't know why, in retrospect. 645 00:33:45,600 --> 00:33:47,500 It seemed kind of obvious. 646 00:33:48,766 --> 00:33:51,666 NARRATOR: First, Mikkel proved that the shotgun technique 647 00:33:51,666 --> 00:33:56,466 could work on dirt DNA several thousand years old. 648 00:33:56,466 --> 00:33:58,733 It really showed us that we could actually 649 00:33:58,733 --> 00:34:01,333 get ancient environmental DNA 650 00:34:01,333 --> 00:34:03,866 even from the very shortest threads 651 00:34:03,866 --> 00:34:06,500 that, that were preserving in the samples. 652 00:34:06,500 --> 00:34:09,966 And the obvious next step would actually be 653 00:34:09,966 --> 00:34:12,466 to take on the most challenging project of them all. 654 00:34:12,466 --> 00:34:15,166 What we refer to as the curse, 655 00:34:15,166 --> 00:34:17,466 the Kap Kobenhavn Formation. 656 00:34:20,200 --> 00:34:22,100 RAGHAVAN: In the early years of ancient DNA, 657 00:34:22,100 --> 00:34:23,700 we had to decide which part 658 00:34:23,700 --> 00:34:25,233 of the genome to look at. 659 00:34:25,233 --> 00:34:28,333 Those are the giveaway parts of the genome 660 00:34:28,333 --> 00:34:29,833 that we call barcodes. 661 00:34:29,833 --> 00:34:32,033 They reveal the identity 662 00:34:32,033 --> 00:34:33,200 of an organism. 663 00:34:33,200 --> 00:34:34,600 We matched those barcodes 664 00:34:34,600 --> 00:34:36,533 to our reference catalog, 665 00:34:36,533 --> 00:34:40,600 but those barcode fragments had to be long enough. 666 00:34:40,600 --> 00:34:43,966 RAGHAVAN: We know that DNA fragments over a hundred base pairs 667 00:34:43,966 --> 00:34:46,500 just don't survive millions of years, 668 00:34:46,500 --> 00:34:49,866 even frozen, high up in the Arctic. 669 00:34:49,866 --> 00:34:53,500 So, shotgun sequencing was a revolution. 670 00:34:53,500 --> 00:34:57,033 Now, instead of targeting a specific part of the genome 671 00:34:57,033 --> 00:35:01,400 with precision, like with a rifle, we're using a shotgun. 672 00:35:01,400 --> 00:35:04,266 A shotgun hits everything. (shotgun fires) 673 00:35:04,266 --> 00:35:05,900 WILLERSLEV: With the shotgun method, 674 00:35:05,900 --> 00:35:09,166 we just sequence all the DNA we can find. 675 00:35:09,166 --> 00:35:13,866 Then we look for matches with every genome sequence 676 00:35:13,866 --> 00:35:16,866 for every organism that we know of. 677 00:35:17,866 --> 00:35:22,133 It takes immense computing power, billions of operations. 678 00:35:22,133 --> 00:35:25,033 And only now are computers powerful enough 679 00:35:25,033 --> 00:35:28,200 to work with fragments down to 30 base pairs. 680 00:35:28,200 --> 00:35:30,866 ♪ 681 00:35:30,866 --> 00:35:34,200 Imagine shredding "War and Peace." 682 00:35:34,200 --> 00:35:38,500 All you have are short phrases, not even sentences. 683 00:35:38,500 --> 00:35:41,300 And you walk into the Library of Congress, 684 00:35:41,300 --> 00:35:43,400 and you start looking for a match 685 00:35:43,400 --> 00:35:46,966 for each one of those phrases, 686 00:35:46,966 --> 00:35:49,866 book by book by book. 687 00:35:49,866 --> 00:35:52,566 There's another "War and Peace" in there somewhere, 688 00:35:52,566 --> 00:35:56,500 but you need to work through millions of other books 689 00:35:56,500 --> 00:35:58,466 before you find a match. 690 00:35:58,466 --> 00:36:03,000 And once you do, your job is to reconstruct 691 00:36:03,000 --> 00:36:07,666 as many pages of that novel as you can. 692 00:36:10,700 --> 00:36:14,866 So we were the first to use shotgun sequencing on dirt. 693 00:36:14,866 --> 00:36:17,300 And when we did, 694 00:36:17,300 --> 00:36:19,533 man, it was powerful. 695 00:36:19,533 --> 00:36:21,600 In science, 696 00:36:21,600 --> 00:36:25,600 moments like this actually feels like magic. 697 00:36:25,600 --> 00:36:27,366 I have no other way of putting it. 698 00:36:27,366 --> 00:36:32,333 It was just like that Christmas Eve 25 years ago. 699 00:36:32,333 --> 00:36:36,100 As if by magic, we were seeing the genetic signatures 700 00:36:36,100 --> 00:36:38,800 of these plants and animals appear. 701 00:36:38,800 --> 00:36:41,166 Bang, bang, bang. 702 00:36:41,166 --> 00:36:43,333 But it's different this time. 703 00:36:43,333 --> 00:36:45,766 Now, there's hundreds-- 704 00:36:45,766 --> 00:36:50,166 fleas, lemmings, arctic hare, geese, caribou. 705 00:36:50,166 --> 00:36:52,766 A whole forest ecosystem: 706 00:36:52,766 --> 00:36:56,433 larch, poplar, willow, spruce, 707 00:36:56,433 --> 00:36:58,633 ash, cedar trees. 708 00:36:58,633 --> 00:37:01,066 We're looking at a long list 709 00:37:01,066 --> 00:37:06,700 of organisms from a place that today is an Arctic desert. 710 00:37:06,700 --> 00:37:10,133 ♪ 711 00:37:10,133 --> 00:37:12,133 NARRATOR: Eske's team had recovered 712 00:37:12,133 --> 00:37:16,000 the genetic fingerprints of a lost world-- 713 00:37:16,000 --> 00:37:21,300 nine land and sea animals, from horseshoe crabs to big mammals; 714 00:37:21,300 --> 00:37:26,100 over a hundred plants, from mosses to forest trees; 715 00:37:26,100 --> 00:37:29,333 and nearly 2,000 other organisms, 716 00:37:29,333 --> 00:37:32,900 including bacteria and plankton, 717 00:37:32,900 --> 00:37:35,366 some of them extinct and many of them 718 00:37:35,366 --> 00:37:38,666 never detected in the Arctic. 719 00:37:38,666 --> 00:37:40,900 But this incredible breakthrough 720 00:37:40,900 --> 00:37:44,333 created another problem. 721 00:37:44,333 --> 00:37:46,433 If you're claiming to have recovered 722 00:37:46,433 --> 00:37:48,100 the world's oldest DNA, 723 00:37:48,100 --> 00:37:51,400 you'd better be very sure about the date. 724 00:37:51,400 --> 00:37:53,266 ♪ 725 00:37:53,266 --> 00:37:55,666 (Willerslev speaking indistinctly) 726 00:37:55,666 --> 00:37:58,533 WILLERSLEV: We knew we were going to get hammered. 727 00:37:58,533 --> 00:38:03,900 Extraordinary claims demand extraordinary evidence, right? 728 00:38:03,900 --> 00:38:08,900 We had to be very sure about the dates from Kap Kobenhavn. 729 00:38:08,900 --> 00:38:12,666 That took two more years of hard work. 730 00:38:12,666 --> 00:38:15,800 ♪ 731 00:38:15,800 --> 00:38:16,933 Eske. 732 00:38:16,933 --> 00:38:19,300 (voiceover): We used a whole set 733 00:38:19,300 --> 00:38:21,233 of different methods. 734 00:38:21,233 --> 00:38:22,933 We looked for organisms in the sediments 735 00:38:22,933 --> 00:38:25,100 that we knew lived on Earth 736 00:38:25,100 --> 00:38:26,800 for a known period of the past. 737 00:38:26,800 --> 00:38:28,733 We used the biological clock 738 00:38:28,733 --> 00:38:32,233 based on how DNA mutates over time. 739 00:38:33,266 --> 00:38:35,966 NARRATOR: And Eske's team used three more independent methods 740 00:38:35,966 --> 00:38:39,800 to date the sediment from Greenland. 741 00:38:39,800 --> 00:38:43,600 When their work was done, they had made a remarkable discovery. 742 00:38:43,600 --> 00:38:49,266 The Cape Copenhagen DNA is at least two million years old. 743 00:38:49,266 --> 00:38:51,400 WILLERSLEV: It's important to understand 744 00:38:51,400 --> 00:38:54,266 that this is the minimum possible age. 745 00:38:54,266 --> 00:38:59,833 Taking all the lines of the dating evidence as a whole, 746 00:38:59,833 --> 00:39:04,133 the most likely age of the Kap Kobenhavn DNA 747 00:39:04,133 --> 00:39:06,500 is actually 2.5 million years. 748 00:39:06,500 --> 00:39:09,100 This puts us into the late Pliocene, 749 00:39:09,100 --> 00:39:14,466 which is the period just before we start having glaciations. 750 00:39:14,466 --> 00:39:16,533 If Eske's DNA is that old, 751 00:39:16,533 --> 00:39:19,700 if it is Pliocene, then that is huge. 752 00:39:20,766 --> 00:39:23,300 NARRATOR: Eske had his hands on DNA 753 00:39:23,300 --> 00:39:26,233 from before the last Ice Age. 754 00:39:26,233 --> 00:39:28,200 WILLERSLEV: Finally, we are catching sight 755 00:39:28,200 --> 00:39:31,566 of the living world that existed in Greenland 756 00:39:31,566 --> 00:39:34,066 before the world grew cold. 757 00:39:35,533 --> 00:39:37,466 That was the moment. 758 00:39:37,466 --> 00:39:42,900 That was when we knew we had something to tell the world. 759 00:39:43,900 --> 00:39:45,166 NARRATOR: Sixteen years 760 00:39:45,166 --> 00:39:48,000 after Eske began collecting dirt in Greenland, 761 00:39:48,000 --> 00:39:50,800 the breakthrough was published in "Nature" magazine. 762 00:39:50,800 --> 00:39:55,200 It was covered by over 400 newspapers around the world. 763 00:39:55,200 --> 00:39:59,633 It even landed on the front page of "The New York Times." 764 00:39:59,633 --> 00:40:03,466 This was one of the biggest science stories of the year. 765 00:40:04,466 --> 00:40:07,666 Until this day, the record for the oldest DNA 766 00:40:07,666 --> 00:40:10,333 was from a single fossil, 767 00:40:10,333 --> 00:40:13,933 a mammoth that lived just over one million years ago, 768 00:40:13,933 --> 00:40:15,066 during the Ice Age. 769 00:40:15,066 --> 00:40:18,800 Using dirt DNA instead of fossils, 770 00:40:18,800 --> 00:40:21,400 Eske's team shattered that record, 771 00:40:21,400 --> 00:40:24,400 opening a window on an unknown living world 772 00:40:24,400 --> 00:40:27,233 more than twice as old as that mammoth. 773 00:40:28,533 --> 00:40:31,833 SHAPIRO: It feels almost magical to be able to infer 774 00:40:31,833 --> 00:40:35,066 such a complete picture of an ancient ecosystem, 775 00:40:35,066 --> 00:40:38,000 from tiny fragments of preserved DNA. 776 00:40:38,000 --> 00:40:40,200 ♪ 777 00:40:40,200 --> 00:40:42,200 When I first heard about the results 778 00:40:42,200 --> 00:40:43,966 from Kap Kobenhavn... (inhales) 779 00:40:45,233 --> 00:40:47,633 I just said to myself, "What?!" 780 00:40:47,633 --> 00:40:49,900 What we're talking about 781 00:40:49,900 --> 00:40:51,400 is pushing the record back 782 00:40:51,400 --> 00:40:52,866 to at least two million years, 783 00:40:52,866 --> 00:40:55,800 and I believe much longer than that. 784 00:40:55,800 --> 00:40:57,733 It was a complete tour de force. 785 00:40:57,733 --> 00:40:59,566 What are my feelings when I first saw this paper, 786 00:40:59,566 --> 00:41:01,633 is, uh, stunned. 787 00:41:01,633 --> 00:41:04,866 I think we just never really thought it would be possible, 788 00:41:04,866 --> 00:41:06,066 after years of trying, 789 00:41:06,066 --> 00:41:08,566 to get DNA from these ancient ecosystems. 790 00:41:10,066 --> 00:41:12,133 We never thought we'd see such a rich 791 00:41:12,133 --> 00:41:16,000 and diverse ecosystem in Greenland. 792 00:41:16,000 --> 00:41:18,400 We're seeing the very last Arctic forests 793 00:41:18,400 --> 00:41:21,966 from a hotter world before the Ice Age. 794 00:41:21,966 --> 00:41:23,533 And these forests are unique. 795 00:41:23,533 --> 00:41:25,033 We have nothing like them today. 796 00:41:25,033 --> 00:41:27,800 (geese honking) 797 00:41:27,800 --> 00:41:32,366 ♪ 798 00:41:32,366 --> 00:41:33,966 WILLERSLEV: I always knew 799 00:41:33,966 --> 00:41:36,400 that there was forest in the High Arctic. 800 00:41:36,400 --> 00:41:41,700 I touched the wood of ancient trees up there. 801 00:41:41,700 --> 00:41:44,966 But when we looked at the sequences from Greenland, 802 00:41:44,966 --> 00:41:49,733 there was one that completely shocked me, 803 00:41:49,733 --> 00:41:52,700 shocked everyone. 804 00:41:52,700 --> 00:41:55,633 (mastodon roars) 805 00:41:55,633 --> 00:42:00,533 To hear that there was mastodon DNA from Kap Kobenhavn, 806 00:42:00,533 --> 00:42:04,700 this just struck me as, "Whoa. How can that be? 807 00:42:04,700 --> 00:42:06,433 That is so far north." 808 00:42:06,433 --> 00:42:08,966 NARRATOR: Relatives of the modern elephant, 809 00:42:08,966 --> 00:42:11,533 mastodons were forest creatures 810 00:42:11,533 --> 00:42:14,666 that died out at the end of the Ice Age. 811 00:42:14,666 --> 00:42:17,600 The closest to Cape Copenhagen their remains have been found 812 00:42:17,600 --> 00:42:22,333 is almost 3,000 miles to the south, in North America. 813 00:42:22,333 --> 00:42:23,600 It comes completely out of the blue. 814 00:42:23,600 --> 00:42:25,766 And it was the first time that we found 815 00:42:25,766 --> 00:42:29,233 such a large animal in Greenland. 816 00:42:29,233 --> 00:42:32,833 ♪ 817 00:42:42,800 --> 00:42:47,533 WILLERSLEV: So, after all those years, we broke the curse 818 00:42:47,533 --> 00:42:49,700 of the Greenland samples. 819 00:42:50,733 --> 00:42:53,133 I guess you can say it was a breakthrough 820 00:42:53,133 --> 00:42:56,633 that immediately became a problem. 821 00:42:56,633 --> 00:42:58,500 The big question, of course, is 822 00:42:58,500 --> 00:43:01,566 how do such DNA survive 823 00:43:01,566 --> 00:43:04,333 beyond the one-million-year-old limit? 824 00:43:05,700 --> 00:43:08,500 That was the mystery we had to solve. 825 00:43:08,500 --> 00:43:11,833 ♪ 826 00:43:11,833 --> 00:43:14,600 It turns out, DNA survived 827 00:43:14,600 --> 00:43:17,166 such an incredible long time 828 00:43:17,166 --> 00:43:21,033 because of minerals in the soil. 829 00:43:22,566 --> 00:43:25,233 DNA is electrically charged. 830 00:43:25,233 --> 00:43:28,933 And many mineral particles that you find in the soil 831 00:43:28,933 --> 00:43:31,833 is also electrically charged. 832 00:43:31,833 --> 00:43:36,000 So, therefore, DNA fragments will basically bind itself 833 00:43:36,000 --> 00:43:41,233 around such sediment particles. 834 00:43:41,233 --> 00:43:44,266 And this will reduce the rate of degradation, 835 00:43:44,266 --> 00:43:46,333 of the spontaneous reaction 836 00:43:46,333 --> 00:43:49,900 that are attacking the DNA and breaking it up. 837 00:43:49,900 --> 00:43:52,666 So, yes, it will still be degraded, 838 00:43:52,666 --> 00:43:54,466 it will still be destroyed, 839 00:43:54,466 --> 00:43:59,833 but the rate by which this is happening is heavily reduced. 840 00:44:01,700 --> 00:44:05,266 It turned out that particularly certain minerals 841 00:44:05,266 --> 00:44:10,366 of clay and quartz binds the DNA very strong. 842 00:44:10,366 --> 00:44:15,766 If bound to clay and quartz, DNA is basically frozen in time. 843 00:44:17,166 --> 00:44:20,100 What is super cool about the Greenland breakthrough, 844 00:44:20,100 --> 00:44:22,233 is the discovery that certain minerals 845 00:44:22,233 --> 00:44:25,500 can freeze DNA in time. 846 00:44:25,500 --> 00:44:28,500 Because this means that everything we thought 847 00:44:28,500 --> 00:44:31,966 about the limits of DNA preservation are out the window. 848 00:44:32,966 --> 00:44:35,666 NARRATOR: Not back to the age of dinosaurs, 849 00:44:35,666 --> 00:44:38,933 but far beyond the old one-million-year limit. 850 00:44:38,933 --> 00:44:40,766 ♪ 851 00:44:40,766 --> 00:44:41,900 WILLERSLEV (voiceover): So, these cores 852 00:44:41,900 --> 00:44:42,900 that no one believed in 853 00:44:42,900 --> 00:44:44,266 turned out to contain 854 00:44:44,266 --> 00:44:46,666 the most amazing treasure. 855 00:44:46,666 --> 00:44:50,433 It just took us 15 years to find out how to get it out. 856 00:44:50,433 --> 00:44:52,566 ...amazing to... 857 00:44:52,566 --> 00:44:54,733 (voiceover): To be honest, I never really lost faith 858 00:44:54,733 --> 00:45:00,500 because every limit we have ever set, we broke. 859 00:45:00,500 --> 00:45:05,033 (birds chirping) 860 00:45:05,033 --> 00:45:07,533 NARRATOR: Until now, what we knew of the living world 861 00:45:07,533 --> 00:45:11,800 before the Ice Age, we learned from fossils. 862 00:45:11,800 --> 00:45:13,700 At the Canadian Museum of Nature, 863 00:45:13,700 --> 00:45:17,400 Natalia Rybczynski only has fragments of bone to study. 864 00:45:18,400 --> 00:45:22,500 But with the spectacular discovery of DNA from Greenland, 865 00:45:22,500 --> 00:45:24,566 finally a detailed portrait 866 00:45:24,566 --> 00:45:27,533 of this lost world is emerging. 867 00:45:27,533 --> 00:45:32,500 And it's even stranger than scientists expected. 868 00:45:32,500 --> 00:45:35,733 WILLERSLEV: This was a really weird environment. 869 00:45:35,733 --> 00:45:40,766 You had a forest where half the year it was dark. 870 00:45:40,766 --> 00:45:46,000 And the other half the year it was sunshine all day around. 871 00:45:46,000 --> 00:45:50,366 This means that all the organisms we are uncovering 872 00:45:50,366 --> 00:45:54,500 had to survive half the year in darkness. 873 00:45:54,500 --> 00:45:57,300 (footsteps on vegetation) 874 00:45:57,300 --> 00:46:00,600 (snuffling, light growling) 875 00:46:00,600 --> 00:46:06,433 ♪ 876 00:46:06,433 --> 00:46:08,633 RYBCZYNSKI: I think the thing that really blew our minds 877 00:46:08,633 --> 00:46:12,833 from the Pliocene is the camel. 878 00:46:12,833 --> 00:46:15,233 NARRATOR: How could this camel, known only 879 00:46:15,233 --> 00:46:17,366 by a few fragments of bone, 880 00:46:17,366 --> 00:46:19,800 survive so far north? 881 00:46:19,800 --> 00:46:22,800 The living world revealed by the Greenland DNA 882 00:46:22,800 --> 00:46:25,033 gives us some clues. 883 00:46:25,033 --> 00:46:26,600 RYBCZYNSKI: When you think about camels today, 884 00:46:26,600 --> 00:46:28,300 it's really easy to imagine 885 00:46:28,300 --> 00:46:30,966 that they evolved to live in the desert. 886 00:46:30,966 --> 00:46:35,066 And this is where the finding of the High Arctic camel 887 00:46:35,066 --> 00:46:36,500 is so mind-blowing, right? 888 00:46:36,500 --> 00:46:39,400 Because it's not in a desert. 889 00:46:39,400 --> 00:46:42,333 It's living a complete opposite to a desert. 890 00:46:42,333 --> 00:46:43,533 It's in a forest. 891 00:46:45,133 --> 00:46:49,033 Ever notice how huge a camel's eye is? 892 00:46:49,033 --> 00:46:50,766 Well, it turns out they have incredible vision, 893 00:46:50,766 --> 00:46:52,533 including night vision. 894 00:46:52,533 --> 00:46:55,800 That's pretty useful when it's dark six months of the year. 895 00:46:55,800 --> 00:46:57,833 (camel grunting) 896 00:46:57,833 --> 00:47:00,333 One of the, uh, most dramatic features 897 00:47:00,333 --> 00:47:02,900 of the camel, it's the hump. (camel gurgles) 898 00:47:02,900 --> 00:47:05,366 It's actually a specialized fat deposit. 899 00:47:05,366 --> 00:47:08,666 And when you think about the importance of fat, 900 00:47:08,666 --> 00:47:10,033 energy storage, 901 00:47:10,033 --> 00:47:11,866 this is something that's also very important 902 00:47:11,866 --> 00:47:15,000 for animals that survive through harsh winters. 903 00:47:16,300 --> 00:47:18,933 The wide feet of camels, 904 00:47:18,933 --> 00:47:20,500 you know, it's listed as one of the traits 905 00:47:20,500 --> 00:47:22,466 that helps them walk over sand, 906 00:47:22,466 --> 00:47:25,266 also would function well in soft snow. 907 00:47:26,433 --> 00:47:28,133 WILLERSLEV: We haven't found camel DNA 908 00:47:28,133 --> 00:47:29,500 from before the Ice Age. 909 00:47:29,500 --> 00:47:30,533 Not yet. 910 00:47:30,533 --> 00:47:31,933 ♪ 911 00:47:31,933 --> 00:47:33,166 But we have now 912 00:47:33,166 --> 00:47:35,133 recreated the forest world 913 00:47:35,133 --> 00:47:37,366 they were living in, and Natalia's fossils 914 00:47:37,366 --> 00:47:39,466 tells us they were there. 915 00:47:41,833 --> 00:47:43,366 This is a forest that stretched 916 00:47:43,366 --> 00:47:47,866 from Greenland to Canada on solid land without barriers. 917 00:47:47,866 --> 00:47:52,766 ♪ 918 00:47:56,033 --> 00:47:58,366 SHAPIRO: We used to believe that ancient DNA could take you back 919 00:47:58,366 --> 00:48:00,200 a few thousand years. 920 00:48:00,200 --> 00:48:02,900 Today, we know we can see millions of years back in time. 921 00:48:04,833 --> 00:48:07,366 NARRATOR: Back to a hotter time, 922 00:48:07,366 --> 00:48:09,900 before the Ice Age, 923 00:48:09,900 --> 00:48:12,600 the Pliocene: 924 00:48:12,600 --> 00:48:15,566 a long-lost epoch that climate scientists 925 00:48:15,566 --> 00:48:19,000 believe may hold a lesson for us today. 926 00:48:20,433 --> 00:48:22,200 MAUREEN RAYMO: The Pliocene's a big 927 00:48:22,200 --> 00:48:24,366 red flashing light, right? 928 00:48:27,933 --> 00:48:30,866 The Pliocene was the last time atmospheric CO2 levels 929 00:48:30,866 --> 00:48:32,133 were the same as today. 930 00:48:32,133 --> 00:48:33,600 You would have to go back 931 00:48:33,600 --> 00:48:37,066 three million years to find a climate equivalent to 932 00:48:37,066 --> 00:48:38,333 what we're doing right now. 933 00:48:38,333 --> 00:48:41,100 That is a CO2 level of about 934 00:48:41,100 --> 00:48:43,833 400 parts per million in the atmosphere. 935 00:48:43,833 --> 00:48:47,233 ♪ 936 00:48:47,233 --> 00:48:50,566 The new Pliocene has begun. 937 00:48:50,566 --> 00:48:51,833 It's called the Anthropocene. 938 00:48:53,066 --> 00:48:55,333 We've already altered Earth's climate. 939 00:48:55,333 --> 00:48:58,266 We're living in a climate that 940 00:48:58,266 --> 00:49:01,933 is about one degree C warmer globally than it should be. 941 00:49:01,933 --> 00:49:06,066 ♪ 942 00:49:06,066 --> 00:49:08,900 The climate of the Pliocene is where we're going. 943 00:49:08,900 --> 00:49:11,633 It's like our instruction manual for what's coming. 944 00:49:11,633 --> 00:49:15,266 (insects buzzing) 945 00:49:15,266 --> 00:49:17,400 RYBCZYNSKI: When the Pliocene ended, 946 00:49:17,400 --> 00:49:19,466 and the Ice Age began, that was a big blow. 947 00:49:19,466 --> 00:49:21,500 But it didn't end life on Earth. 948 00:49:21,500 --> 00:49:24,033 All life around us has its evolutionary roots 949 00:49:24,033 --> 00:49:26,066 in a hotter world, including us. 950 00:49:27,133 --> 00:49:30,566 NARRATOR: And that hotter world could hold lessons 951 00:49:30,566 --> 00:49:33,800 for our own survival. 952 00:49:33,800 --> 00:49:35,100 Greenland proves 953 00:49:35,100 --> 00:49:37,733 we can go much deeper in time 954 00:49:37,733 --> 00:49:38,900 than what we thought we would. 955 00:49:38,900 --> 00:49:40,333 ♪ 956 00:49:40,333 --> 00:49:42,833 We now have the technology 957 00:49:42,833 --> 00:49:44,733 to go even farther back in time, 958 00:49:44,733 --> 00:49:46,566 potentially many millions of years. 959 00:49:48,166 --> 00:49:49,566 SHAPIRO: We have access to the genetic codes 960 00:49:49,566 --> 00:49:51,633 of plants and animals that survived 961 00:49:51,633 --> 00:49:53,666 in different climates, 962 00:49:53,666 --> 00:49:55,800 hotter climates, drier climates. 963 00:49:55,800 --> 00:49:57,633 If we can sequence the genomes 964 00:49:57,633 --> 00:50:00,766 of those ancient organisms, maybe they can help us. 965 00:50:00,766 --> 00:50:02,600 And I think we're gonna need help. 966 00:50:02,600 --> 00:50:05,633 NARRATOR: The rescue effort has already started. 967 00:50:05,633 --> 00:50:08,500 ♪ 968 00:50:10,066 --> 00:50:13,900 Scientists in Copenhagen have identified a gene 969 00:50:13,900 --> 00:50:15,966 from the Greenland DNA that helped 970 00:50:15,966 --> 00:50:17,933 poplar trees grow in the extreme 971 00:50:17,933 --> 00:50:20,100 light conditions of the High Arctic. 972 00:50:20,100 --> 00:50:25,033 And they've put that gene into a modern barley plant. 973 00:50:25,033 --> 00:50:28,800 One day, when our climate is much warmer, 974 00:50:28,800 --> 00:50:32,500 this barley might thrive at the top of the world, 975 00:50:32,500 --> 00:50:35,566 just as those ancient poplar trees did. 976 00:50:35,566 --> 00:50:37,766 WILLERSLEV: This is a food plant 977 00:50:37,766 --> 00:50:41,333 engineered for a hot future. 978 00:50:41,333 --> 00:50:43,166 ♪ 979 00:50:43,166 --> 00:50:46,400 We are stealing genetic secrets of the past 980 00:50:46,400 --> 00:50:50,300 so we can rescue the future. 981 00:50:52,033 --> 00:50:55,600 I want to do my part to rescue the future. 982 00:50:55,600 --> 00:50:58,300 ♪ (woman vocalizing) 983 00:50:58,300 --> 00:50:59,500 We are going to sequence 984 00:50:59,500 --> 00:51:03,700 thousands, millions of ancient genomes 985 00:51:03,700 --> 00:51:07,466 from sediment samples all over the world. 986 00:51:08,733 --> 00:51:11,666 Because we are now using robots 987 00:51:11,666 --> 00:51:13,533 across the entire pipeline, 988 00:51:13,533 --> 00:51:16,200 we can do 200 samples a week. 989 00:51:17,066 --> 00:51:20,466 We are starting an industrial revolution 990 00:51:20,466 --> 00:51:23,600 in ancient DNA sequencing. 991 00:51:25,366 --> 00:51:27,000 ♪ 992 00:51:27,000 --> 00:51:30,533 NARRATOR: Arctic barley could be just the beginning. 993 00:51:30,533 --> 00:51:34,866 Scientists are gearing up to put ancient genes into rice, wheat, 994 00:51:34,866 --> 00:51:38,800 and other foods to help them thrive in a warming world. 995 00:51:38,800 --> 00:51:44,133 ♪ 996 00:51:44,133 --> 00:51:46,000 Today we take for granted 997 00:51:46,000 --> 00:51:51,200 that all organisms are shedding DNA around in the environment. 998 00:51:51,200 --> 00:51:54,900 But, once, this was a new idea. 999 00:51:54,900 --> 00:52:00,633 It all started with that dog pooping in the rain. 1000 00:52:00,633 --> 00:52:03,433 And that is why we can do this, 1001 00:52:03,433 --> 00:52:09,066 where a little bit of dirt contains an entire living world. 1002 00:52:31,766 --> 00:52:39,300 ♪ 1003 00:52:40,933 --> 00:52:48,466 ♪ 1004 00:52:54,200 --> 00:53:01,433 ♪