When I was a young boy, I used to gaze through the microscope of my father at the insects in amber that he kept in the house. And they were remarkably well preserved, morphologically just phenomenal. And we used to imagine that someday, they would actually come to life and they would crawl out of the resin, and, if they could, they would fly away.
Kad sam bio dečak piljio sam kroz mikroskop mog oca u insekte u ćilibaru koje je čuvao u kući. I oni su bili izuzetno dobro očuvani, morfološki fenomenalno. I zamišljali smo da bi jednog dana mogli da ožive i ispuze iz smole i ako bi mogli, odlete.
If you had asked me 10 years ago whether or not we would ever be able to sequence the genome of extinct animals, I would have told you, it's unlikely. If you had asked whether or not we would actually be able to revive an extinct species, I would have said, pipe dream. But I'm actually standing here today, amazingly, to tell you that not only is the sequencing of extinct genomes a possibility, actually a modern-day reality, but the revival of an extinct species is actually within reach, maybe not from the insects in amber -- in fact, this mosquito was actually used for the inspiration for "Jurassic Park" — but from woolly mammoths, the well preserved remains of woolly mammoths in the permafrost.
Da ste me pitali pre 10 godina da li ćemo ikada moći da odredimo genom istrebljenih životinja, rekao bih vam da je to malo verovatno. Da ste pitali da li bismo mogli da oživimo istrebljene vrste, rekao bih, pusti snovi. Ali danas sam ovde, zapanjujuće, da bih vam rekao da je, ne samo određivanje istrebljenih genoma moguće, u stvari realnost u modernom vremenu, već je i oživljavanje istrebljenih vrsta nadohvat ruke, možda ne insekata u ćilibaru - ovaj komarac je u stvari iskorišćen kao inspiracija za "Park iz doba jure" - već od runastih mamuta, dobro očuvanih ostataka runastih mamuta iz permafrosta.
Woollies are a particularly interesting, quintessential image of the Ice Age. They were large. They were hairy. They had large tusks, and we seem to have a very deep connection with them, like we do with elephants. Maybe it's because elephants share many things in common with us. They bury their dead. They educate the next of kin. They have social knits that are very close. Or maybe it's actually because we're bound by deep time, because elephants, like us, share their origins in Africa some seven million years ago, and as habitats changed and environments changed, we actually, like the elephants, migrated out into Europe and Asia.
Oni su posebno interesantni, suštinska slika Ledenog doba. Bili su veliki. Bili su dlakavi. Imali su velike kljove i izgleda da smo vrlo duboko povezani sa njima, kao što smo i sa slonovima. Možda je to zato što slonovi imaju mnogo zajedničkog sa nama. Oni sahranjuju svoje mrtve, odgajaju najbliže srodnike. Imaju društvene veze koje su veoma bliske. Ili je to možda zato što smo vezani dugim vremenom, jer slonovi, kao i mi, vode svoje poreklo iz Afrike od pre nekih sedam miliona godina i kako su se staništa i okruženja menjala, mi smo se, kao i slonovi, selili u Evropu i Aziju.
So the first large mammoth that appears on the scene is meridionalis, which was standing four meters tall weighing about 10 tons, and was a woodland-adapted species and spread from Western Europe clear across Central Asia, across the Bering land bridge and into parts of North America. And then, again, as climate changed as it always does, and new habitats opened up, we had the arrival of a steppe-adapted species called trogontherii in Central Asia pushing meridionalis out into Western Europe. And the open grassland savannas of North America opened up, leading to the Columbian mammoth, a large, hairless species in North America. And it was really only about 500,000 years later that we had the arrival of the woolly, the one that we all know and love so much, spreading from an East Beringian point of origin across Central Asia, again pushing the trogontherii out through Central Europe, and over hundreds of thousands of years migrating back and forth across the Bering land bridge during times of glacial peaks and coming into direct contact with the Columbian relatives living in the south, and there they survive over hundreds of thousands of years during traumatic climatic shifts. So there's a highly plastic animal dealing with great transitions in temperature and environment, and doing very, very well. And there they survive on the mainland until about 10,000 years ago, and actually, surprisingly, on the small islands off of Siberia and Alaska until about 3,000 years ago. So Egyptians are building pyramids and woollies are still living on islands.
Prvi veliki mamut koji se pojavljuje na sceni je meridionalis koji je bio visok 4 metra težio oko 10 tona i bio adaptiran na šumovite oblasti i rasprostranjen od zapadne Evrope, preko centralne Azije, preko Beringovog kopnenog mosta i u delovima Severne Amerike. I onda, ponovo, kako se klima promenila kao što se stalno dešava, nova staništa su se otvorila, imali smo dolazak vrste adaptirane na stepu zvane trogontherii (stepski mamut) u centralnoj Aziji koja je potisnula meridionalisa u zapadnu Evropu. I otvorene travnate savane u Severnoj Americi su se otvorile vodeći do kolumbijskog mamuta, velike bezdlake vrste u Severnoj Americi. I u stvari samo oko 500.000 godina kasnije se pojavio runasti mamut, onaj kog svi znamo i toliko volimo i širio se od istočno-beringovske tačke nastanka preko centralne Azije, opet potiskujući stepskog mamuta ka centralnoj Evropi i tokom stotina i hiljada godina migrirajući napred i nazad preko Beringovog kopnenog mosta tokom vremena glečerskih vrhunaca i dolazeći u direktan kontakt sa kolumbijskim rođacima sa juga i tamo su preživeli stotinama i hiljadama godina tokom traumatičnih klimatskih promena. To je vrlo prilagodljiva životinja koja se suočavala sa velikim prelazima u temperaturi i u okruženju i vrlo dobro ih podnosila. I tu su oni preživljavali na kopnu sve do pre oko 10.000 godina, u stvari, iznenađujuće, na malim ostrvima na obalama Sibira i Aljaske, do pre 3.000 godina. Dok Egipćani grade piramide, runasti mamuti još uvek žive na ostrvima.
And then they disappear. Like 99 percent of all the animals that have once lived, they go extinct, likely due to a warming climate and fast-encroaching dense forests that are migrating north, and also, as the late, great Paul Martin once put it, probably Pleistocene overkill, so the large game hunters that took them down.
I onda nestaju. Kao i 99 posto svih životinja koje su jednom živele, oni su istrebljeni, verovatno zbog klimatskog otopljavanja i brzog napredovanja gustih šuma koje su se pomerale ka severu i takođe, kao što je pokojni, veliki Pol Martin jednom rekao, verovatno prekomernog ubijanja u pleistocenu, tako da su ih lovci na veliku divljač istrebili.
Fortunately, we find millions of their remains strewn across the permafrost buried deep in Siberia and Alaska, and we can actually go up there and actually take them out. And the preservation is, again, like those insects in [amber], phenomenal. So you have teeth, bones with blood which look like blood, you have hair, and you have intact carcasses or heads which still have brains in them.
Srećom, nalazimo milione njihovih ostataka rasutih po permafrostu zakopane duboko u Sibiru i na Aljasci i možemo da odemo tamo i izvadimo ih. I očuvanost je opet, kao kod onih insekata u ćilibaru, fenomenalna. Imate zube, kosti sa krvlju koja izgleda kao krv, imate dlake i imate netaknuta tela ili glave koje još uvek imaju mozak.
So the preservation and the survival of DNA depends on many factors, and I have to admit, most of which we still don't quite understand, but depending upon when an organism dies and how quickly he's buried, the depth of that burial, the constancy of the temperature of that burial environment, will ultimately dictate how long DNA will survive over geologically meaningful time frames. And it's probably surprising to many of you sitting in this room that it's not the time that matters, it's not the length of preservation, it's the consistency of the temperature of that preservation that matters most.
Očuvanje i preživljavanje DNK zavisi od mnogo faktora i moram priznati da većinu i dalje ne razumemo potpuno, ali u zavisnosti od toga kada organizam umre i koliko brzo je pokopan, dubine zakopavanja, konstantnosti temperature u okruženju tog mesta, to će na kraju odrediti koliko dugo će DNK preživeti kroz geološki značajne vremenske okvire. I verovatno je iznenađujuće mnogima od vas koji sedite u ovoj prostoriji, da nije vreme ono što je važno niti je to dužina čuvanja, već je najvažnija postojanost temperature čuvanja.
So if we were to go deep now within the bones and the teeth that actually survived the fossilization process, the DNA which was once intact, tightly wrapped around histone proteins, is now under attack by the bacteria that lived symbiotically with the mammoth for years during its lifetime. So those bacteria, along with the environmental bacteria, free water and oxygen, actually break apart the DNA into smaller and smaller and smaller DNA fragments, until all you have are fragments that range from 10 base pairs to, in the best case scenarios, a few hundred base pairs in length. So most fossils out there in the fossil record are actually completely devoid of all organic signatures. But a few of them actually have DNA fragments that survive for thousands, even a few millions of years in time. And using state-of-the-art clean room technology, we've devised ways that we can actually pull these DNAs away from all the rest of the gunk in there, and it's not surprising to any of you sitting in the room that if I take a mammoth bone or a tooth and I extract its DNA that I'll get mammoth DNA, but I'll also get all the bacteria that once lived with the mammoth, and, more complicated, I'll get all the DNA that survived in that environment with it, so the bacteria, the fungi, and so on and so forth. Not surprising then again that a mammoth preserved in the permafrost will have something on the order of 50 percent of its DNA being mammoth, whereas something like the Columbian mammoth, living in a temperature and buried in a temperate environment over its laying-in will only have 3 to 10 percent endogenous.
Ako bismo otišli duboko u kosti i zube koji su preživeli proces fosilizacije, DNK koja je bila netaknuta, čvrsto omotana oko proteina histona, sada je pod napadom bakterija koje su živele u simbiozi sa mamutom godinama u toku njegovog života. Tako ove bakterije zajedno sa bakterijama iz okruženja, slobodnom vodom i vazduhom, u stvari razbijaju DNK na sve manje i manje DNK fragmente sve dok ne ostanu samo fragmenti u opsegu od 10 baznih parova do, u najboljem scenariju, nekoliko stotina baznih parova u dužinu. Većina fosila koji su otkriveni su u stvari potpuno oskudni u svim organskim potpisima. Ali nekoliko njih ima DNK fragmente koji preživljavaju hiljadama, pa čak i nekoliko miliona godina. Koristeći najsavremeniju tehnologiju čiste sobe, pronašli smo načine da izdvojimo ove DNK od ostale prljavštine tamo i nije iznenađujuće ni za koga od vas koji sedite ovde da ako uzmem kost ili zub mamuta i izdvojim njihov DNK, dobiću DNK mamuta, ali ću dobiti i sve bakterije koje su jednom živele sa mamutom i što je komplikovanije, dobiću sve DNK koje su preživele u tom okruženju, bakterije, gljive i tako dalje. Nije iznenađujuće, opet, da će mamut sačuvan u permafrostu imati otprilike 50 posto mamutske DNK dok će kolumbijski mamut koji je živeo i zakopan je u umerenim temperaturnim uslovima biti samo 3 do 10 posto endogen.
But we've come up with very clever ways that we can actually discriminate, capture and discriminate, the mammoth from the non-mammoth DNA, and with the advances in high-throughput sequencing, we can actually pull out and bioinformatically re-jig all these small mammoth fragments and place them onto a backbone of an Asian or African elephant chromosome. And so by doing that, we can actually get all the little points that discriminate between a mammoth and an Asian elephant, and what do we know, then, about a mammoth?
Ali smislili smo vrlo domišljate načine da odvojimo, uhvatimo i odvojimo mamutsku od nemamutske DNK i sa prednostima visoko propustljivog sekvenciranja možemo da izvučemo i bioinformatički ponovo sastavimo sve ove male fragmente mamuta i stavimo ih na osnovu hromozoma azijskog ili afričkog slona. I time u stvari možemo da dobijemo sve male tačke koje prave razliku između mamuta i azijskog slona i šta znamo onda o mamutu?
Well, the mammoth genome is almost at full completion, and we know that it's actually really big. It's mammoth. So a hominid genome is about three billion base pairs, but an elephant and mammoth genome is about two billion base pairs larger, and most of that is composed of small, repetitive DNAs that make it very difficult to actually re-jig the entire structure of the genome.
Mamutov genom je skoro potpuno dovršen i znamo da je veoma veliki. Mamutski. Genom hominida je oko 3 milijarde baznih parova ali genom slona i mamuta je za oko 2 milijarde baznih parova veći i najveći njegov deo je sastavljen od malih, ponavljajućih DNK što čini veoma teškim ponovno sastavljanje cele strukture genoma.
So having this information allows us to answer one of the interesting relationship questions between mammoths and their living relatives, the African and the Asian elephant, all of which shared an ancestor seven million years ago, but the genome of the mammoth shows it to share a most recent common ancestor with Asian elephants about six million years ago, so slightly closer to the Asian elephant.
Imajući ovu informaciju, možemo da odgovorimo na jedno od interesantnih pitanja odnosa između mamuta i njihovih živih rođaka, afričkog i azijskog slona, koji svi dele zajedničkog predaka od pre sedam miliona godina, ali genom mamuta deli skorijeg predaka sa azijskim slonovima pre šest miliona godina, znači malo bliže azijskom slonu.
With advances in ancient DNA technology, we can actually now start to begin to sequence the genomes of those other extinct mammoth forms that I mentioned, and I just wanted to talk about two of them, the woolly and the Columbian mammoth, both of which were living very close to each other during glacial peaks, so when the glaciers were massive in North America, the woollies were pushed into these subglacial ecotones, and came into contact with the relatives living to the south, and there they shared refugia, and a little bit more than the refugia, it turns out. It looks like they were interbreeding. And that this is not an uncommon feature in Proboscideans, because it turns out that large savanna male elephants will outcompete the smaller forest elephants for their females. So large, hairless Columbians outcompeting the smaller male woollies. It reminds me a bit of high school, unfortunately.
Sa napretkom u tehnologiji drevne DNK sad možemo da počnemo da sekvenciramo genome onih drugih istrebljenih oblika mamuta koje sam pomenuo i samo sam hteo da govorim o dva, o runastom i kolumbijskom mamutu, koji su živeli veoma blizu jedan drugoga tokom glečerskih vrhunaca, kad su glečeri bili veliki u Severnoj Americi runasti mamuti su potisnuti u subglečerske ekotone i došli su u dodir sa rođacima koji žive na jugu i tamo su delili pribežište i, kako se ispostavilo, malo više od pribežišta. Izgleda da su se međusobno sparivali. I ovo nije bila neuobičajena karakteristika među surlašima, jer se ispostavilo da će veliki mužjaci slona iz savane pobediti manje šumske slonove u borbi za njihove ženke. Tako da veliki bezdlaki kolumbijski mamuti pobeđuju manje mužjake runastog mamuta. Podseća me pomalo na srednju školu, nažalost.
(Laughter)
(Smeh)
So this is not trivial, given the idea that we want to revive extinct species, because it turns out that an African and an Asian elephant can actually interbreed and have live young, and this has actually occurred by accident in a zoo in Chester, U.K., in 1978. So that means that we can actually take Asian elephant chromosomes, modify them into all those positions we've actually now been able to discriminate with the mammoth genome, we can put that into an enucleated cell, differentiate that into a stem cell, subsequently differentiate that maybe into a sperm, artificially inseminate an Asian elephant egg, and over a long and arduous procedure, actually bring back something that looks like this. Now, this wouldn't be an exact replica, because the short DNA fragments that I told you about will prevent us from building the exact structure, but it would make something that looked and felt very much like a woolly mammoth did.
Ovo nije beznačajno, imajući u vidu ideju da želimo da oživimo istrebljene vrste, jer se ispostavilo da afrički i azijski slon u stvari mogu da se međusobno razmnožavaju i imaju žive mladunce i ovo se stvarno dogodilo slučajno u zoološkom vrtu u Česteru, u Velikoj Britaniji 1978. To znači da možemo da uzmemo hromozome azijskog slona, modifikujemo ih u sve ove položaje koje smo sada mogli da izdvojimo sa genomom mamuta, možemo da stavimo to u ćeliju sa uklonjenim jedrom, diferenciramo to u matičnu ćeliju, posle toga diferenciramo to možda u spermu, veštački oplodimo jaje azijskog slona i dugom i napornom procedurom povratimo nešto što izgleda ovako. Ovo ne bi bila tačna replika jer kratki fragmenti DNK o kojima sam vam pričao će nas sprečiti da napravimo tačnu strukturu, ali bi se napravilo nešto što izgleda vrlo slično kao što je izgledao runasti mamut.
Now, when I bring up this with my friends, we often talk about, well, where would you put it? Where are you going to house a mammoth? There's no climates or habitats suitable. Well, that's not actually the case. It turns out that there are swaths of habitat in the north of Siberia and Yukon that actually could house a mammoth. Remember, this was a highly plastic animal that lived over tremendous climate variation. So this landscape would be easily able to house it, and I have to admit that there [is] a part of the child in me, the boy in me, that would love to see these majestic creatures walk across the permafrost of the north once again, but I do have to admit that part of the adult in me sometimes wonders whether or not we should.
Kada ovo pomenem u razgovoru sa prijateljima, obično pričamo o tome gde biste ga stavili? Gde ćete smestiti mamuta? Nema pogodnih klimata ni staništa. Pa, to nije sasvim tačno. Izgleda da ima puno staništa na severu Sibira i Jukona gde bi mogao da se nastani mamut. Sećate se, ovo je vrlo prilagodljiva životinja koja je preživela ogromne varijacije klime. Tako da bi u ovom predelu mogao lako da se nastani i moram priznati da nema detinjeg dela u meni, dečaka u meni koji bi voleo da vidi ova veličanstvena stvorenja kako šetaju po permafrostu severa još jednom, već moram priznati da deo odrasle osobe u meni se ponekad pita da li bi trebalo ili ne.
Thank you very much.
Hvala puno.
(Applause)
(Aplauz)
Ryan Phelan: Don't go away. You've left us with a question. I'm sure everyone is asking this. When you say, "Should we?" it feels like you're reticent there, and yet you've given us a vision of it being so possible. What's your reticence?
Rajan Felan: Nemojte da idete. Ostavili ste nas s pitanjem. Sigurna sam da se svi pitaju ovo. Kad kažete: "Da li bi trebalo?" čini se da ste uzdržani, a ipak ste nam dali viziju da je to moguće. Zašto ste uzdržani?
Hendrik Poinar: I don't think it's reticence. I think it's just that we have to think very deeply about the implications, ramifications of our actions, and so as long as we have good, deep discussion like we're having now, I think we can come to a very good solution as to why to do it. But I just want to make sure that we spend time thinking about why we're doing it first.
Hendrik Poinar: Ne mislim da je to uzdržanost. Samo mislim da treba da duboko razmislimo o implikacijama, grananju naših dela i dok god imamo dobru, duboku diskusiju kao što je imamo sada, mislim da možemo da dođemo do vrlo dobrog rešenja zašto da to uradimo. Ali ja samo hoću da se uverim da pre toga provodimo vreme razmišljajući o tome zašto to radimo.
RP: Perfect. Perfect answer. Thank you very much, Hendrik.
R.P.: Savršeno. Savršen odgovor. Hvala puno Hendriče.
HP: Thank you. (Applause)
H.P.: Hvala vam. (Aplauz)