How to Bring an Extinct Animal Back to Life

imagine a world in which woolly mammoths roam the plains of siberia where dodos flock on the shores of mauritius or where 12-foot tall saber-toothed cats stroll through the woods of north america well maybe no thanks to that last one but a world in which extinct animals are brought back to life may not be limited to the imagination for much longer de-extinction is the process of bringing back to life an extinct animal species it's an idea that's been around for a while but was perhaps fully propelled into the public consciousness by the 1993 film jurassic park while resurrected dinosaurs remain firmly in the realms of science fiction the de-extinction of other animals is a much closer horizon we are currently living through earth's sixth mass extinction period called the holocene extinction this mass extinction closely correlates to human activity through hunting deforestation pollution climate change and other side effects of human expansion we may have lost close to seven percent of all species on the planet but de-extinction could be one way of resurrecting lost species and protecting those most at risk today and with recent developments in genome sequencing genetic engineering and cloning scientists have now begun to resurrect recently extinct species and have their sights set on those lost further back in time so is a jurassic park style zoo filled with extinct species actually possible what would we need to do to bring back animals that would otherwise be lost forever [Music] to fill our hypothetical zoo one of the first decisions would be which animals to bring back to life this would depend on our goal and there are a number of reasons why we might want to de-extinct a range of different species one big motivation for de-extinction is to increase biodiversity having a variety of animals plants and insects in an ecosystem is important as all of these different creatures perform different vital roles predators like wolves and bears keep populations of smaller mammals in check beavers build dams that slow down rivers to create safe environments for other water-loving animals and pollinators like bees and wasps help plants reproduce if one animal dies out it can cause knock-on effects that destabilize the entire ecosystem de-extincting animals that are essential to managing and maintaining their original ecosystems could help return those ecosystems back to health another reason we might want to bring back lost species is to learn from them many of the medicines and technological innovations we use today have been developed from initial discoveries in nature extinct species may hold answers to some of our most puzzling research questions and de-extinction techniques can also be used in the race to save endangered species we may not be able to bring back every lost animal but we might be able to boost populations that are at risk of disappearing now and there may be a moral obligation to bring back animals that humans are responsible for eradicating the extinction rate now is thought to be a thousand times faster than before humans became the planet's dominant species and a quarter of all mammals now are at risk of extinction we've got a lot to make up for however there are limitations it won't be possible to bring back every extinct species with current technology that relies heavily on dna and well-preserved tissue it's unlikely we'll be able to de-extinct anything that died out more than 10 000 years ago because dna doesn't last that long when an organism dies cells break down exposing dna in the nucleus to damage by enzymes and microorganisms this means that in really old tissue dna is either non-existent or only present in tiny amounts so for better or worse that rules out the dinosaurs it's also much harder to de-extinct birds or reptiles compared to mammals because we know so much more about mammalian reproduction compared to birds and reptiles but if we had a mammal in mind which lived within the last few thousand years how would we go about bringing them back there are three main routes currently being explored in the push to de-extinct animals and they all have pros and cons we had lots of time and a few acres of land we could try back breeding back breeding is a process where lost traits are bred back into living species sort of converting an existing species back into a previous form to understand this method let's look at an attempt by researchers in south africa to recreate the quagga an extinct subspecies of zebra quagas and zebras are pretty similar but where zebras are covered in stripes quaggas only have stripes on the front half of their bodies quaggas also have brown coloring on their rear quaggas were common in south africa until european settlers hunted them into extinction in the late 19th century because zebras are a closely related species to the extinct quagga they are the starting point of the study to begin recreating the quagga scientists select individual zebras that express the same or very similar traits to the extinct species such as zebras with fewer stripes on the back half of their bodies or zebras with more brown coloring on their back half then once these individual animals have been identified they are bred together any offspring that have inherited the desired traits will be bred again hopefully producing a new generation that carry a mix of extinct species traits this process needs to be repeated until the resulting animal is as close to the extinct species as possible the back breeding project started over 30 years ago and in that time has produced multiple breeding groups of nearly quaggas after several generations of the selective breeding the animals aren't quite the same as the originals but they do have the half stripes and brown rears of their extinct relatives but there are some downsides and challenges to back breeding that mean it might not be a suitable approach for every animal first of all we'd need a really close relative of the extinct species to act as our starting point for animals extinct many thousands of years ago this may not be possible it's also a really long process the gestation period for a zebra for example is 12 months if we need to repeat the breeding process several times over it could be years or even decades before a herd of our extinct species is ready and it's an imprecise process although genome sequencing and in vitro fertilization can help breeders be more selective about what gets passed on you can't guarantee the traits you expect to see in the new generation will materialize but luckily even if we don't have a starter species or we don't have time to breed multiple generations there are some other options another route to de-extinction is cloning clones are exact genetic replicas of another organism and arise all the time in nature bacteria clone themselves as a means of reproduction and identical twins are technically clones of each other but cloning can also be done in the lab we've cloned lots of animals including buffalo dogs and camels so how could we use cloning to bring back a long dead species the most reliable method is probably scnt somatic cell nuclear transfer this is the method pioneered by the creators of dolly the sheep the first cloned mammal and surprisingly scientists have already attempted this method it began in 1999 when researchers captured the last surviving pyrenean ibex a female named celia they obtained skin biopsies and froze the tissue in liquid nitrogen then in 2009 those skin cells were used to clone celia in the first ever case of actual de-extinction first the nuclei from the frozen skin cells were removed and injected into donor eggs taken from domestic goats which had their own nuclei removed by adding some chemicals and a jolt of electricity the process of embryonic development was started after a few days of growth in the lab the embryos were implanted into a surrogate mother either a spanish ibex or an ibex goat hybrid the resulting fetuses had exactly the same dna as the extinct animal of the 208 embryos the researchers implanted only seven pregnancies resulted and just one ibex made it to term this was a huge accomplishment the first ever extinct animal brought back into existence however the baby ibex died almost immediately from respiratory failure most embryos derived from clones don't develop properly and we don't fully know why research suggests that it's not just one stage of the cloning process that is causing damage to the resulting embryos but in fact many if not all stages contribute from the act of moving the nucleus from one cell to another to the use of chemicals to kickstart embryonic development but scientists are not ready to give up so quickly instead setting their sights on an even loftier goal de-extincting one of the greatest megafauna of all time the woolly mammoth in 2019 a major breakthrough in the effort to bring back this incredible animal occurred when a team in japan successfully transferred the nucleus from a frozen mammoth cell into the egg of a mouse the nucleus came from a 28 000 year old preserved mammoth named yuka the goal of the experiment was not to create some kind of mammoth mouse hybrid it was to see if this ancient dna had the potential to be re-awakened could the cellular machinery in a mouse egg fix the damaged parts of the mammoth dna and kick-start the dna replication necessary for embryonic development if it could that would suggest there is potential for harvested preserved mammoth dna to be brought back to life through cloning and the mouse cell machinery did manage to fix some parts of the damaged dna and there were some very early signs of the mechanics that underpin dna replication but ultimately the mouse egg could only do so much the mammoth dna was too badly damaged and so it's nearly impossible to reconstitute it enough to actually bring it back to life for now cloning a mammoth is still a far-off dream but research like this adds to the field of knowledge that might get us there one day but there is one other approach we could try and it has elements of back breeding and cloning a new technology opening up options for de-extinction is genetic engineering more specifically crispr technology crispr cast 9 is a type of molecular scissor that can cut dna at a pre-programmed position this means strands of dna can be added removed or edited at specific points in the dna we could insert genes from an extinct animal into the dna of a close relative creating a hybrid with the phenotype the physical attributes of the extinct species to do this we'd first need to sequence the extinct animal genome if we have preserved dna for example from mammoth tissue in the permafrost we can use genome sequencing to work out its entire genetic code and use tests to work out which genes are linked to the phenotype of the extinct species if we then compare the extinct species genetic code to that of its closest living relative we could work out where they differ finally we could copy and paste the genes we want from the existing animal into the host animal dna researchers at harvard university are trying to use this crispr technology to splice mammoth genes into asian elephant dna but it's a monumental task there are around 1.4 million known gene mutations separating mammoths and asian elephants and not all of the mutations will relate to the mammoth phenotype it will take a long while yet to work out which mammoth genes need to be swapped into elephant dna to recreate a woolly mammoth but the idea may be the most promising yet and one day we may just see the first baby mammoth to live in 10 000 years [Music] although none of these methods are perfect they are certainly bringing us closer to the de-extinction of lost species and to protecting and reviving endangered animal populations but before we get too excited about bringing back everything from mammoths to thylacines to dodos we might want to pause and decide whether we should bring back any lost species at all because as cool as it might be to create a de-extinction safari park there are some risks while reintroducing recently extinct species might prove beneficial to existing ecosystems long dead species could end up doing more harm than good because of the changes those ecosystems have undergone in the intervening period it could create similar problems to those we've seen when releasing non-native species into new areas when the poisonous cane toad was introduced to australia to control the grey-backed cane beetle the toad quickly spread and pushed out native toad populations an extinct species might out-compete one that has developed in its absence or the ecosystems that once supported an extinct species might no longer be a suitable home the chinese river dolphin was polluted out of the yangtze river and things haven't improved since they wouldn't survive there today if and when we are able to successfully and reliably bring back lost species particularly those that have been extinct for thousands of years we will need to think carefully about whether these are risks we want to take but every day between 30 and 150 species of animal die out on earth for good alongside conservation efforts de-extinction could be a potential avenue to undo some of the damage that humans have enacted on the planet one of the most mysterious and strange animals to ever live on our planet was the thylacine found in australia tasmania and new guinea it was the largest carnivorous marsupial with a body that looks like a cross between a cat and a dog also known as the tasmanian tiger it was wiped from the continent of australia 3 000 years ago and survived in tasmania until the 1930s when humans finally hunted it into extinction over recent years there have been many reports of thylacine sightings in the jungles of tasmania giving some hope that a few individuals remain but these sightings are almost all exaggerated or are cases of mistaken identity sadly the thylacine is still very much extinct but it may not be forever geneticists are working to resurrect this enigmatic animal with crispr and cloning working with a tiny relative of the thylacine a numbat to see how scientists are working to understand these marsupial genetics and to see how close they are to making a living thylacine a reality you should watch resurrecting tasmanian tigers on curiosity stream curiosity stream is a streaming platform with thousands of high quality documentaries like this one and now curiositystream has partnered with us to offer an incredible deal by signing up to curiositystream you now also get a subscription to nebula nebula is a streaming platform made by me and several other educational youtube content creators it's a place where we can upload our videos and podcasts free and a place where we can experiment with new original content by signing up to the bundle deal you'll get access to both curiosity stream 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Channel: Real Science

Views: 709,541

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Id: wJOXCpSHG1M

Length: 17min 41sec (1061 seconds)

Published: Sat Apr 10 2021