Bring back the woolly mammoth!
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0:01 - 0:03When I was a young boy,
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0:03 - 0:05I used to gaze through the microscope of my father
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0:05 - 0:09at the insects in amber that he kept in the house.
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0:09 - 0:11And they were remarkably well preserved,
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0:11 - 0:13morphologically just phenomenal.
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0:13 - 0:16And we used to imagine that someday,
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0:16 - 0:17they would actually come to life
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0:17 - 0:19and they would crawl out of the resin,
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0:19 - 0:22and, if they could, they would fly away.
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0:22 - 0:24If you had asked me 10 years ago whether or not
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0:24 - 0:28we would ever be able to sequence the genome of extinct animals,
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0:28 - 0:30I would have told you, it's unlikely.
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0:30 - 0:32If you had asked whether or not we would actually be able
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0:32 - 0:34to revive an extinct species,
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0:34 - 0:36I would have said, pipe dream.
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0:36 - 0:38But I'm actually standing here today, amazingly,
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0:38 - 0:40to tell you that not only is the sequencing
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0:40 - 0:44of extinct genomes a possibility, actually a modern-day reality,
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0:44 - 0:49but the revival of an extinct species is actually within reach,
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0:49 - 0:51maybe not from the insects in amber --
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0:51 - 0:53in fact, this mosquito was actually used
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0:53 - 0:55for the inspiration for "Jurassic Park" —
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0:55 - 0:57but from woolly mammoths, the well preserved remains
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0:57 - 1:00of woolly mammoths in the permafrost.
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1:00 - 1:02Woollies are a particularly interesting,
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1:02 - 1:04quintessential image of the Ice Age.
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1:04 - 1:06They were large. They were hairy.
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1:06 - 1:08They had large tusks, and we seem to have
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1:08 - 1:11a very deep connection with them, like we do with elephants.
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1:11 - 1:13Maybe it's because elephants share
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1:13 - 1:15many things in common with us.
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1:15 - 1:18They bury their dead. They educate the next of kin.
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1:18 - 1:21They have social knits that are very close.
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1:21 - 1:24Or maybe it's actually because we're bound by deep time,
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1:24 - 1:27because elephants, like us, share their origins in Africa
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1:27 - 1:29some seven million years ago,
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1:29 - 1:32and as habitats changed and environments changed,
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1:32 - 1:36we actually, like the elephants, migrated out
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1:36 - 1:38into Europe and Asia.
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1:38 - 1:41So the first large mammoth that appears on the scene
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1:41 - 1:44is meridionalis, which was standing four meters tall
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1:44 - 1:48weighing about 10 tons, and was a woodland-adapted species
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1:48 - 1:51and spread from Western Europe clear across Central Asia,
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1:51 - 1:53across the Bering land bridge
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1:53 - 1:55and into parts of North America.
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1:55 - 1:58And then, again, as climate changed as it always does,
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1:58 - 2:00and new habitats opened up,
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2:00 - 2:02we had the arrival of a steppe-adapted species
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2:02 - 2:04called trogontherii in Central Asia
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2:04 - 2:07pushing meridionalis out into Western Europe.
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2:07 - 2:10And the open grassland savannas of North America
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2:10 - 2:12opened up, leading to the Columbian mammoth,
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2:12 - 2:14a large, hairless species in North America.
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2:14 - 2:17And it was really only about 500,000 years later
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2:17 - 2:20that we had the arrival of the woolly,
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2:20 - 2:22the one that we all know and love so much,
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2:22 - 2:25spreading from an East Beringian point of origin
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2:25 - 2:28across Central Asia, again pushing the trogontherii
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2:28 - 2:30out through Central Europe,
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2:30 - 2:32and over hundreds of thousands of years
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2:32 - 2:35migrating back and forth across the Bering land bridge
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2:35 - 2:37during times of glacial peaks
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2:37 - 2:39and coming into direct contact
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2:39 - 2:42with the Columbian relatives living in the south,
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2:42 - 2:45and there they survive over hundreds of thousands of years
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2:45 - 2:47during traumatic climatic shifts.
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2:47 - 2:51So there's a highly plastic animal dealing with great transitions
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2:51 - 2:54in temperature and environment, and doing very, very well.
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2:54 - 2:58And there they survive on the mainland until about 10,000 years ago,
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2:58 - 3:01and actually, surprisingly, on the small islands off of Siberia
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3:01 - 3:04and Alaska until about 3,000 years ago.
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3:04 - 3:05So Egyptians are building pyramids
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3:05 - 3:08and woollies are still living on islands.
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3:08 - 3:10And then they disappear.
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3:10 - 3:12Like 99 percent of all the animals that have once lived,
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3:12 - 3:15they go extinct, likely due to a warming climate
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3:15 - 3:17and fast-encroaching dense forests
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3:17 - 3:19that are migrating north,
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3:19 - 3:22and also, as the late, great Paul Martin once put it,
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3:22 - 3:24probably Pleistocene overkill,
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3:24 - 3:26so the large game hunters that took them down.
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3:26 - 3:28Fortunately, we find millions of their remains
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3:28 - 3:31strewn across the permafrost buried deep
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3:31 - 3:34in Siberia and Alaska, and we can actually go up there
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3:34 - 3:36and actually take them out.
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3:36 - 3:38And the preservation is, again,
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3:38 - 3:40like those insects in [amber], phenomenal.
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3:40 - 3:44So you have teeth, bones with blood
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3:44 - 3:46which look like blood, you have hair,
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3:46 - 3:47and you have intact carcasses or heads
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3:47 - 3:50which still have brains in them.
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3:50 - 3:53So the preservation and the survival of DNA
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3:53 - 3:55depends on many factors, and I have to admit,
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3:55 - 3:57most of which we still don't quite understand,
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3:57 - 3:59but depending upon when an organism dies
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3:59 - 4:04and how quickly he's buried, the depth of that burial,
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4:04 - 4:07the constancy of the temperature of that burial environment,
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4:07 - 4:09will ultimately dictate how long DNA will survive
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4:09 - 4:12over geologically meaningful time frames.
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4:12 - 4:14And it's probably surprising to many of you
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4:14 - 4:17sitting in this room that it's not the time that matters,
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4:17 - 4:19it's not the length of preservation,
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4:19 - 4:23it's the consistency of the temperature of that preservation that matters most.
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4:23 - 4:25So if we were to go deep now within the bones
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4:25 - 4:28and the teeth that actually survived the fossilization process,
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4:28 - 4:32the DNA which was once intact, tightly wrapped
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4:32 - 4:34around histone proteins, is now under attack
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4:34 - 4:37by the bacteria that lived symbiotically with the mammoth
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4:37 - 4:39for years during its lifetime.
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4:39 - 4:42So those bacteria, along with the environmental bacteria,
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4:42 - 4:46free water and oxygen, actually break apart the DNA
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4:46 - 4:48into smaller and smaller and smaller DNA fragments,
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4:48 - 4:51until all you have are fragments that range
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4:51 - 4:53from 10 base pairs to, in the best case scenarios,
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4:53 - 4:56a few hundred base pairs in length.
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4:56 - 4:58So most fossils out there in the fossil record
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4:58 - 5:01are actually completely devoid of all organic signatures.
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5:01 - 5:03But a few of them actually have DNA fragments
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5:03 - 5:05that survive for thousands,
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5:05 - 5:09even a few millions of years in time.
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5:09 - 5:11And using state-of-the-art clean room technology,
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5:11 - 5:14we've devised ways that we can actually pull these DNAs
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5:14 - 5:16away from all the rest of the gunk in there,
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5:16 - 5:18and it's not surprising to any of you sitting in the room
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5:18 - 5:21that if I take a mammoth bone or a tooth
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5:21 - 5:24and I extract its DNA that I'll get mammoth DNA,
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5:24 - 5:27but I'll also get all the bacteria that once lived with the mammoth,
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5:27 - 5:30and, more complicated, I'll get all the DNA
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5:30 - 5:32that survived in that environment with it,
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5:32 - 5:35so the bacteria, the fungi, and so on and so forth.
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5:35 - 5:37Not surprising then again that a mammoth
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5:37 - 5:39preserved in the permafrost will have something
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5:39 - 5:42on the order of 50 percent of its DNA being mammoth,
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5:42 - 5:44whereas something like the Columbian mammoth,
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5:44 - 5:47living in a temperature and buried in a temperate environment
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5:47 - 5:50over its laying-in will only have 3 to 10 percent endogenous.
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5:50 - 5:53But we've come up with very clever ways
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5:53 - 5:56that we can actually discriminate, capture and discriminate,
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5:56 - 5:58the mammoth from the non-mammoth DNA,
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5:58 - 6:00and with the advances in high-throughput sequencing,
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6:00 - 6:03we can actually pull out and bioinformatically
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6:03 - 6:06re-jig all these small mammoth fragments
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6:06 - 6:09and place them onto a backbone
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6:09 - 6:11of an Asian or African elephant chromosome.
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6:11 - 6:14And so by doing that, we can actually get all the little points
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6:14 - 6:17that discriminate between a mammoth and an Asian elephant,
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6:17 - 6:20and what do we know, then, about a mammoth?
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6:20 - 6:23Well, the mammoth genome is almost at full completion,
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6:23 - 6:26and we know that it's actually really big. It's mammoth.
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6:26 - 6:29So a hominid genome is about three billion base pairs,
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6:29 - 6:31but an elephant and mammoth genome
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6:31 - 6:34is about two billion base pairs larger, and most of that
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6:34 - 6:36is composed of small, repetitive DNAs
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6:36 - 6:41that make it very difficult to actually re-jig the entire structure of the genome.
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6:41 - 6:43So having this information allows us to answer
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6:43 - 6:45one of the interesting relationship questions
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6:45 - 6:48between mammoths and their living relatives,
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6:48 - 6:50the African and the Asian elephant,
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6:50 - 6:53all of which shared an ancestor seven million years ago,
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6:53 - 6:55but the genome of the mammoth shows it to share
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6:55 - 6:58a most recent common ancestor with Asian elephants
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6:58 - 6:59about six million years ago,
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6:59 - 7:02so slightly closer to the Asian elephant.
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7:02 - 7:04With advances in ancient DNA technology,
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7:04 - 7:06we can actually now start to begin to sequence
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7:06 - 7:10the genomes of those other extinct mammoth forms that I mentioned,
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7:10 - 7:11and I just wanted to talk about two of them,
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7:11 - 7:13the woolly and the Columbian mammoth,
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7:13 - 7:16both of which were living very close to each other
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7:16 - 7:19during glacial peaks,
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7:19 - 7:21so when the glaciers were massive in North America,
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7:21 - 7:23the woollies were pushed into these subglacial ecotones,
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7:23 - 7:26and came into contact with the relatives living to the south,
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7:26 - 7:28and there they shared refugia,
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7:28 - 7:31and a little bit more than the refugia, it turns out.
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7:31 - 7:33It looks like they were interbreeding.
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7:33 - 7:35And that this is not an uncommon feature
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7:35 - 7:37in Proboscideans, because it turns out
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7:37 - 7:40that large savanna male elephants will outcompete
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7:40 - 7:43the smaller forest elephants for their females.
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7:43 - 7:45So large, hairless Columbians
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7:45 - 7:47outcompeting the smaller male woollies.
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7:47 - 7:50It reminds me a bit of high school, unfortunately.
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7:50 - 7:52(Laughter)
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7:52 - 7:55So this is not trivial, given the idea that we want
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7:55 - 7:57to revive extinct species, because it turns out
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7:57 - 7:59that an African and an Asian elephant
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7:59 - 8:01can actually interbreed and have live young,
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8:01 - 8:03and this has actually occurred by accident in a zoo
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8:03 - 8:06in Chester, U.K., in 1978.
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8:06 - 8:09So that means that we can actually take Asian elephant chromosomes,
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8:09 - 8:11modify them into all those positions we've actually now
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8:11 - 8:14been able to discriminate with the mammoth genome,
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8:14 - 8:16we can put that into an enucleated cell,
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8:16 - 8:19differentiate that into a stem cell,
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8:19 - 8:21subsequently differentiate that maybe into a sperm,
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8:21 - 8:24artificially inseminate an Asian elephant egg,
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8:24 - 8:27and over a long and arduous procedure,
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8:27 - 8:30actually bring back something that looks like this.
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8:30 - 8:32Now, this wouldn't be an exact replica,
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8:32 - 8:34because the short DNA fragments that I told you about
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8:34 - 8:37will prevent us from building the exact structure,
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8:37 - 8:38but it would make something that looked and felt
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8:38 - 8:42very much like a woolly mammoth did.
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8:42 - 8:44Now, when I bring up this with my friends,
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8:44 - 8:47we often talk about, well, where would you put it?
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8:47 - 8:49Where are you going to house a mammoth?
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8:49 - 8:51There's no climates or habitats suitable.
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8:51 - 8:52Well, that's not actually the case.
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8:52 - 8:55It turns out that there are swaths of habitat
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8:55 - 8:57in the north of Siberia and Yukon
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8:57 - 8:58that actually could house a mammoth.
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8:58 - 9:01Remember, this was a highly plastic animal
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9:01 - 9:03that lived over tremendous climate variation.
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9:03 - 9:06So this landscape would be easily able to house it,
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9:06 - 9:10and I have to admit that there isn't a part of the child in me,
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9:10 - 9:11the boy in me, that would love to see
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9:11 - 9:14these majestic creatures walk across the permafrost
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9:14 - 9:16of the north once again, but I do have to admit
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9:16 - 9:19that part of the adult in me sometimes wonders
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9:19 - 9:21whether or not we should.
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9:21 - 9:23Thank you very much.
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9:23 - 9:28(Applause)
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9:28 - 9:29Ryan Phelan: Don't go away.
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9:29 - 9:31You've left us with a question.
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9:31 - 9:35I'm sure everyone is asking this. When you say, "Should we?"
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9:35 - 9:37it feels like you're reticent there,
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9:37 - 9:40and yet you've given us a vision of it being so possible.
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9:40 - 9:42What's your reticence?
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9:42 - 9:43Hendrik Poinar: I don't think it's reticence.
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9:43 - 9:47I think it's just that we have to think very deeply
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9:47 - 9:49about the implications, ramifications of our actions,
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9:49 - 9:51and so as long as we have good, deep discussion
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9:51 - 9:53like we're having now, I think
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9:53 - 9:56we can come to a very good solution as to why to do it.
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9:56 - 9:58But I just want to make sure that we spend time
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9:58 - 10:00thinking about why we're doing it first.
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10:00 - 10:02RP: Perfect. Perfect answer. Thank you very much, Hendrik.
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10:02 - 10:05HP: Thank you. (Applause)
- Title:
- Bring back the woolly mammoth!
- Speaker:
- Hendrik Poinar
- Description:
-
It’s the dream of kids all around the world to see giant beasts walk the Earth again. Could -- and should -- that dream be realized? Hendrik Poinar gives an informative talk on the next -- really -- big thing: The quest to engineer a creature that looks very much like our furry friend, the woolly mammoth. The first step, to sequence the woolly genome, is nearly complete. And it’s huge. (Filmed at TEDxDeExtinction.)
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDTalks
- Duration:
- 10:22
Morton Bast edited English subtitles for Bring back the woolly mammoth! | ||
Thu-Huong Ha edited English subtitles for Bring back the woolly mammoth! | ||
Thu-Huong Ha edited English subtitles for Bring back the woolly mammoth! | ||
Thu-Huong Ha approved English subtitles for Bring back the woolly mammoth! | ||
Thu-Huong Ha edited English subtitles for Bring back the woolly mammoth! | ||
Morton Bast accepted English subtitles for Bring back the woolly mammoth! | ||
Morton Bast edited English subtitles for Bring back the woolly mammoth! | ||
Joseph Geni edited English subtitles for Bring back the woolly mammoth! |