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UNDERSTAND DE-EXTINCTION Harvard’s Prof George Church is working on resurrecting the mammoth 2 zebras. So scientists are choosing the zebras that look most like quaggas and letting them breed. The aim, over successive generations, is to create animals that look like quaggas. Other projects, however, involve assisted reproduction and some rather elegant genetics. Some are using cloning; others, stem cell science. For example, Prof George Church at Harvard Medical School aims to create a mammoth by ‘editing’ mammoth genes into elephant cells. Will these animals be the same as the originals? No, they can never be exactly the same. When he is done, Church will have created not a true mammoth, but an elephant with a sprinkling of judiciously placed mammoth DNA. It will have long, shaggy fur, thick rolls of insulating body fat, and haemoglobin that can ferry oxygen around the body at sub-zero temperatures. This will be an animal that looks like a mammoth, but is really an elephant whose DNA has been altered so it can live in the cold. You could call it a ‘mammophant’ if you like, or an ‘elemoth’. Added to that, we now realise that all animals are a product of their DNA and of the environment in which they live, along with the interaction between the two. Created in a lab, nurtured in the womb of a modern elephant, and raised in a world that has changed radically since mammoths went extinct thousands of years ago, the experiences of this newage pachyderm will be different to those of its Ice Age doppelgänger… all of which will conspire to make it less similar to the original woolly mammoth. But does this matter? Many will argue that, if the de-extinct animal looks and acts like its predecessor, then that’s good enough. Could we resurrect dinosaurs? Sadly, a real-life Jurassic Park is out of the question. There are limitations on which species can undergo de-extinction. First up, scientists need to have a source of the animal’s DNA. Sometimes this comes from preserved museum specimens or from cells that have been collected from live animals and frozen away. Sometimes it can come from fossils. But DNA disintegrates over time, meaning that after a couple of million years there is simply no DNA left. Dinosaurs famously went extinct 65 million years ago, so their DNA is lost forever. No DNA, no dinosaurs. And if you’re hoping to meet a dodo, that icon of extinction, then don’t hold your breath either. Although it died out comparatively recently – a few hundred years ago – its final resting place, Mauritius, was simply too hot to preserve its DNA. 2 74 Although the dodo only died out in the 16th Century, we don’t have any DNA samples to clone it JARGON BUSTER CLONING This is one of the principle methods used to bring back certain animals. DNA from an adult cell is coaxed into a more youthful state, which is then used to create an animal that’s almost genetically identical to the donor. ECOSYSTEM This is a biological community of interacting life forms and the space they live in. Healthy ecosystems are essential to the survival of life on Earth: they provide services including purifying the air, pollinating our crops and sequestering carbon. GENE EDITING The ability of scientists to alter the DNA of living things with pinpoint accuracy. The core components of DNA can now be removed, replaced or added to at will using a process called CRISPR-Cas9. RESURRECTION BIOLOGY Another term for de-extinction. This blend of high-tech methods is enabling scientists to bring back species from the brink of extinction and beyond. STEM CELL These versatile ‘shapeshi ing’ cells can turn into other cell types. Scientists have made northern white rhino stem cells, and next plan to use them to produce eggs and sperm for rhino IVF. X 2 : G E T T Y P H O T O S

HOW TO SAVE THE NORTHERN WHITE RHINO The last three northern white rhinos are unable to breed naturally. A Berlin-based team hopes to de-extinct this animal using IVF and advanced stem cell biology PLAN A: NATURAL EGGS AND SPERM PLAN B: ARTIFICIAL EGGS AND SPERM Skin cells from 12 di erent northern white rhinos have been stored Researchers will collect eggs from the female, Najin, and her daughter Fatu Sperm from Sudan, the last male northern white rhino, along with four other males, has been collected and frozen Add in a handful of extra genes Eggs IVF Sperm Stem cells Embryo Embryo is transferred into the uterus of a female southern white rhino, the northern white rhino’s closest living relative A healthy de-extinct northern white rhino is born WHAT WE STILL DON’T KNOW I C S A C U T E G R A P H : I O N I L L U S T R AT 1 HOW CLONING WORKS Although we’ve been cloning animals for years, we still don’t understand how it actually works. During the process, DNA inside an adult cell is somehow reprogrammed to a more youthful state, so that it can drive embryonic development. It’s like restoring the factory se ing on your phone, but no one knows exactly how it happens or how to fully control it. Crack that, and scientists stand a be er chance of creating healthy, viable animals. 2 HOW RESURRECTED ANIMALS WILL BE PROTECTED To qualif y for legal protec t ion, an organism must be listed as endangered, but for that, the animal must be living in the wild. The first few generations of any newly resurrected species would be kept in captivity while researchers checked their health, so during this time their legal status would be uncertain. Without protection, the animals could be threatened by poaching or habitat loss. 3 HOW DE-EXTINCT ANIMALS WILL FARE IN THE WILD When it comes to releasing the animals, all we can do is study their previous ecology, and send them into the most suitable environment available. We’ll then need to monitor them carefully: it’s vital to know why a species went extinct first time round, to make sure it doesn’t happen again. With each successive re-wilding a empt, we’ll learn more about maximising the animals’ chances of survival. 75

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HOW TO SAVE THE NORTHERN WHITE RHINO

The last three northern white rhinos are unable to breed naturally. A Berlin-based team hopes to de-extinct this animal using IVF and advanced stem cell biology

PLAN A: NATURAL EGGS AND SPERM

PLAN B: ARTIFICIAL EGGS AND SPERM

Skin cells from 12 di erent northern white rhinos have been stored

Researchers will collect eggs from the female, Najin, and her daughter Fatu

Sperm from Sudan, the last male northern white rhino, along with four other males, has been collected and frozen

Add in a handful of extra genes

Eggs

IVF

Sperm

Stem cells

Embryo

Embryo is transferred into the uterus of a female southern white rhino, the northern white rhino’s closest living relative

A healthy de-extinct northern white rhino is born

WHAT WE STILL DON’T KNOW

I C S

A C U T E G R A P H

:

I O N

I L L U S T R AT

1 HOW CLONING WORKS Although we’ve been cloning animals for years, we still don’t understand how it actually works. During the process, DNA inside an adult cell is somehow reprogrammed to a more youthful state, so that it can drive embryonic development. It’s like restoring the factory se ing on your phone, but no one knows exactly how it happens or how to fully control it. Crack that, and scientists stand a be er chance of creating healthy, viable animals.

2 HOW RESURRECTED ANIMALS WILL BE PROTECTED To qualif y for legal protec t ion, an organism must be listed as endangered, but for that, the animal must be living in the wild. The first few generations of any newly resurrected species would be kept in captivity while researchers checked their health, so during this time their legal status would be uncertain. Without protection, the animals could be threatened by poaching or habitat loss.

3 HOW DE-EXTINCT ANIMALS WILL FARE IN THE WILD When it comes to releasing the animals, all we can do is study their previous ecology, and send them into the most suitable environment available. We’ll then need to monitor them carefully: it’s vital to know why a species went extinct first time round, to make sure it doesn’t happen again. With each successive re-wilding a empt, we’ll learn more about maximising the animals’ chances of survival.

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