The Big Question: Will scientists ever be able to resurrect long-extinct animals by cloning?

Why are we asking this now?

Scientists in Japan have refined a cloning technique that has enabled researchers to clone apparently healthy mice from the frozen corpse of a mouse that had been kept in a freezer for 16 years at a temperature of -20C. They employed the same techniques that scientists used to create Dolly the sheep, but added an extra stage where they effectively repeated part of the cloning process, which enabled them to successfully produce cloned offspring. The scientists believe the study shows that it might be possible in the future to use the same techniques to clone creatures from the frozen tissue of animals found buried in permafrost regions, for example, the frozen corpses of mammoths.

Who carried out this work and why?

The team was led by Teruhiko Wakayama of the Riken Centre for Developmental Biology in Kobe, Japan. He was interested in adapting the Dolly method of cloning, which involves taking the nucleus of a cell and inserting it into an unfertilised egg cell that has had its own nucleus removed. After a jolt of electricitythe unfertilised egg develops into an early embryo, just as if it had beenfertilised by a sperm cell.

This was how Dolly herself wascreated. However, unlike Dolly, the resulting mouse embryos in the Japanese study were not inserted into surrogate mothers but broken apart to retrieve individual embryonic stem cells. These stem cells were then inserted into another batch of unfertilised egg cells and, after yet another jolt or two of electricity, the result was the creation of early, cloned embryos. Only at this stage were the embryos implanted into surrogate mothers, which then gave birth to the clones of the original frozen mouse that had died 16 years previously.

Is this the first time that scientists have produced clones from dead animals?

No. In fact Dolly herself was cloned from a sheep that had died long before. Dolly was born in 1996. In Dolly's case, scientists had taken tissue from the udder of Dolly's clone and carefully frozen it using special chemicals called "cryopreservatives". These prevent the formation of damaging ice crystals inside the cells. Dolly was therefore the clone of a frozen animal that had died many years before she was born. Indeed, when one national newspaper learnt that Dolly was the clone of a dead animal, it famously asked the question: "Can we now raise the dead?" on its front page.

Can we now raise the dead?

It depends what you mean. Dolly was the clone of a dead animal, and scientifically it means that the dead animal's entire genome was "resurrected" once more in the body of another individual. But if this were ever to happen to a human being, few people would consider that the deceased person had been raised from the dead as a result of having a living clone. It's no more true than saying that when a person dies, he or she has been "raised from the dead" if they happen to have an identical twin who is still alive. However, what concerns some people is whether these sorts of scientific developments will lead to individuals storing their bodies, or parts of them, in order for that their cells might be cloned in the future – if or when it is scientifically and legally possible to do so.

So will it be possible to resurrect extinct animals?

This is what Wakayama and hiscolleagues tentatively propose in their research paper published in the Proceedings of the National Academy of Sciences. They pointout that all clones so far produced from dead animals have been created from quick-frozen tissue that has been meticulously kept at very cold temperatures without thawing, using cryopreservation. This does not happen in real life.

As the scientists say: "In dead specimens frozen in natural conditions such as permafrost tundra, the cells of tissue will presumably bind strongly to each other and freeze gradually after death due to the large body size. It remains to be shown whether nuclei can be collected from the whole bodies frozen withoutcryoprotectants, and whether they will be viable for use in generating offspring following nuclear transfer. This is an important question with potential application in the cloning of extinct animals frozen in permafrost, or specimens collected opportunistically from endangered species in the field without access to sophisticated laboratory facilities."

Has anyone tried to "resurrect" extinct animals?

Scientists have tried with some success to extract DNA from various extinct mammals, such as mammoths and the Tasmanian tiger, but cloning poses a whole set of different and more intractable problems. The first concerns the difficulty of extracting cells with perfectly preserved DNA, since it degrades over time. Corpses frozen in permafrost for several thousand years are likely to have suffered repeated thawing and freezing that will damage both the cells and their DNA.

Another problem is trying to find suitable non-extinct animals to act as surrogate egg donors and mothers. For the mammoth, the African elephant might be the best choice, although there may be important biological differences that pose insuperable barriers. One problem has to do with mitochondrial DNA, which is passed on down the maternal line through the egg cell. An elephant's mitochondria may simply not work in a mammoth clone.

Could cloning be used to protect living species from extinction?

Some scientists are suggesting this as a last-ditch measure to safeguard threatened animals that are difficult to breed in captivity. However, cloning is never going to be the panacea to the threat of extinction. The biggest problems faced by large endangered animals are habitat loss, human encroachment on their territories, hunting and climate change. Cloning animals on the verge of extinction could help a species to hang on in zoos and parks, but it does little to generate the genetic diversity that is so important for the long-term survival of species. It also does nothing to address the root causes of extinction.

Will this latest cloning development ever be used on people?

One can never say never in science. But it is illegal in Britain to clone babies and this technique will, if applied in full on human tissue, result in the birth of cloned individuals. Unless there is a change in the law, it is therefore unlikely that anyone will ever attempt to clone babies from dead people – in this country at least. Cloning from the grave, as one newspaper put it yesterday, is still a very long way from reality for all sorts of ethical, legal and scientific reasons.

What further research is necessary in this area?

Quite a lot. For a start, showing that it is possible to produce clones from a corpse stored in a laboratory freezer kept at a constant temperature is not the same as being able to clone from a dead body kept in a precarious state of preservation. It is an important step forward, but it will be many years before it can have a practical use.

Should we rely on cloning to protect endangered species?


* It offers hope for species that cannot be bred in captivity with conventional reproductive methods.

* It means that we can preserve the unique combination of genes found in some animals.

* Cloning would make extinction obsolete because animal genomes could be preserved in perpetuity.


* Cloning does nothing to address the underlying problems faced by endangered animals.

* Cloning bypasses sexual reproduction, which generates critical individual differences within a species.

* Cloning is no solution to extinction but it could be used to justify inaction towards endangered species.

Start your day with The Independent, sign up for daily news emails
Arts and Entertainment
The Doctor and Clara have their first real heart to heart since he regenerated in 'Deep Breath'
Arts and Entertainment
James Hewitt has firmly denied being Harry’s father
arts + ents
Arts and Entertainment
Jamie Oliver
filmTV chef Jamie Oliver turned down role in The Hobbit
The official police photograph of Dustin Diamond taken after he was arrested in Wisconsin
peopleDownfall of the TV star charged with bar stabbing
Life and Style
Arts and Entertainment
Jeremy Clarkson, left, and Richard Hammond upset the locals in South America
tvReview: Top Gear team flee Patagonia as Christmas special reaches its climax in the style of Butch and Sundance
Ashley Barnes of Burnley scores their second goal
footballMan City vs Burnley match report
Arts and Entertainment
Peter Mayhew as Chewbacca alongside Harrison Ford's Han Solo in 'Star Wars'
ebooksA year of political gossip, levity and intrigue from the sharpest pen in Westminster
Arts and Entertainment
Man of action: Christian Bale stars in Exodus: Gods and Kings
Life and Style
Apple showed no sign of losing its talent for product launches with the new, slightly larger iPhone 6 making headlines
techSecurity breaches and overhyped start-ups dominated a year in which very little changed (save the size of your phone)
Arts and Entertainment
Catherine (Sarah Lancashire) in Happy Valley ((C) Red Productions/Ben Blackall)
Arts and Entertainment
Clueless? Locked-door mysteries are the ultimate manifestation of the cerebral detective story
booksAs a new collection of the genre’s best is published, its editor explains the rules of engagement
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: LGV Driver - Category C or C+E

£23000 - £26000 per annum: Recruitment Genius: This national Company that manu...

Recruitment Genius: Sales Consultant - OTE £30,000

£13000 - £30000 per annum: Recruitment Genius: Scotland's leading life insuran...

Recruitment Genius: Maintenance Assistant

£25000 - £30000 per annum: Recruitment Genius: A Maintenance Assistant is requ...

Recruitment Genius: Business Manager

£32000 - £40000 per annum: Recruitment Genius: A Business Manager is required ...

Day In a Page

A timely reminder of the bloody anniversary we all forgot

A timely reminder of the bloody anniversary we all forgot

Who remembers that this week we enter the 150th anniversary year of the end of the American Civil War, asks Robert Fisk
Homeless Veterans appeal: Former soldiers pay their respects to a friend who also served

Homeless Veterans appeal

Former soldiers pay their respects to a friend who also served
Downfall of Dustin 'Screech' Diamond, the 'Saved By The Bell' star charged with bar stabbing

Scarred by the bell

The downfall of the TV star charged with bar stabbing
Why 2014 was a year of technological let-downs

Why 2014 was a year of technological let-downs

Security breaches and overhyped start-ups dominated a year in which very little changed (save the size of your phone)
Cuba's golf revolution: But will the revolutionary nation take 'bourgeois' game to its heart?

Will revolutionary Cuba take 'bourgeois' golf to its heart?

Fidel Castro ridiculed the game – but now investment in leisure resort projects is welcome
The Locked Room Mysteries: As a new collection of the genre’s best is published, its editor Otto Penzler explains the rules of engagement

The Locked Room Mysteries

As a new collection of the genre’s best is published, its editor explains the rules of engagement
Amy Adams on playing painter Margaret Keane in Tim Burton's Big Eyes

How I made myself Keane

Amy Adams hadn’t wanted to take the role of artist Margaret Keane, because she’d had enough of playing victims. But then she had a daughter, and saw the painter in a new light
Ed Richards: Parting view of Ofcom chief. . . we hate jokes on the disabled

Parting view of Ofcom chief... we hate jokes on the disabled

Bad language once got TV viewers irate, inciting calls to broadcasting switchboards. But now there is a worse offender, says retiring head of the media watchdog, Ed Richards
A look back at fashion in 2014: Wear in review

Wear in review

A look back at fashion in 2014
Ian Herbert: My 10 hopes for sport in 2015. Might just one of them happen?

Ian Herbert: My 10 hopes for sport in 2015

Might just one of them happen?
War with Isis: The West needs more than a White Knight

The West needs more than a White Knight

Despite billions spent on weapons, the US has not been able to counter Isis's gruesome tactics, says Patrick Cockburn
Return to Helmand: Private Davey Graham recalls the day he was shot by the Taliban

'The day I was shot by the Taliban'

Private Davey Graham was shot five times during an ambush in 2007 - it was the first, controversial photograph to show the dangers our soldiers faced in Helmand province
Revealed: the best and worst airlines for delays

Revealed: the best and worst airlines for delays

Many flyers are failing to claim compensation to which they are entitled, a new survey has found
The stories that defined 2014: From the Scottish independence referendum to the Ice Bucket Challenge, our writers voice their opinions

The stories that defined 2014

From the Scottish independence referendum to the Ice Bucket Challenge, our writers voice their opinions
Stoke-on-Trent becomes first British city to be classified as 'disaster resilient' by the United Nations

Disaster looming? Now you know where to head...

Which British city has become the first to be awarded special 'resilience' status by the UN?