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TEDxDeExtinction

Hendrik Poinar: Bring back the woolly mammoth!

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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 talks about the next 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.

- Evolutionary geneticist
Hendrik Poinar is a geneticist and biological anthropologist who focuses on extracting ancient DNA. He currently has his sights set on sequencing the genome of the woolly mammoth -- and cloning it. Full bio

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

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About the speaker:

Hendrik Poinar - Evolutionary geneticist
Hendrik Poinar is a geneticist and biological anthropologist who focuses on extracting ancient DNA. He currently has his sights set on sequencing the genome of the woolly mammoth -- and cloning it.

Why you should listen

As a child Hendrik Poinar never imagined that the insects his father kept around the house, extinct and preserved in amber, could someday be brought to life. Well that's exactly what Poinar has devoted his career to doing. Today he is a molecular evolutionary geneticist and biological anthropologist at McMaster University in Ontario, where he is the principal investigator at the Ancient DNA Centre. Poinar's focus is on extracting and preserving DNA from paleontological remains -- precisely what he thought impossible as a kid.

And Poinar's newest project is much, much bigger than those insects from his childhood: He wants to bring back the woolly mammoth. In 2006 he and his team started working on sequencing the mammoth genome, based on DNA extracted from well-preserved remains found in Yukon and Siberia. With the mapping nearly complete, Poinar will next turn to engineering an animal very closely resembling the woolly mammoth.

More profile about the speaker
Hendrik Poinar | Speaker | TED.com