Waking the dead Living for the past ... Professor Mike Archer with a thylacine skull. Professor Mike Archer's small office at the University of New South Wales is stuffy - the windows and blinds are so old they no longer open - and chaotic, with bones, skulls and chunks of limestone everywhere, jostling for space with books and stacks of paper. The half-assembled skeleton of a huge cave bear rears up over the clutter. "It was too big for the room," Archer explains regretfully. It's very different from the light-filled eerie overlooking Sydney he enjoyed as the high-profile director of the Australian Museum in 2000, when he made headlines around the world with his ambitious plan to clone the extinct thylacine, also known as the Tasmanian tiger. Although a little greyer now at 68, the palaeontologist remains as bold and indefatigable as ever. "One foot over the precipice - that's the fun area for me," he says cheerfully. Which is where he is now as leader of the Lazarus Project, the Australian scientific team that in March revealed its extraordinary progress in attempting to bring an extinct species back to life. At a gathering in Washington DC of leading researchers into the quest for species revival, or de-extinction as it's known, Archer announced his team had created cloned embryos containing the DNA of an extinct creature, Australia's southern gastric-brooding frog. Producing the embryos, by implanting the extinct frog's DNA in donor frog eggs, brings Archer's team one step closer to undoing extinction, and one step ahead of teams around the world. American stem-cell scientist Dr Robert Lanza was in the audience in Washington. "Mike Archer is a very courageous guy and one of the most visionary scientists I know," he says. If the gastric-brooding frog is resurrected, it will be a scientific achievement of enormous proportions. We're used to getting over speed bumps ... we'll find a way. It could also be a precedent for bringing back from the dead myriad lost species. Australia has one of the world's worst tallies - more than 50 species extinct since white settlement, with about 180 more endangered. Archer is determined to change that and more than ever, technology is on his side. Science's ability to decode and manipulate life at its earliest stages has been sprinting ahead since the first mammal to be cloned, Dolly the sheep, was born in 1996. Though DNA more than 10,000 years old is unlikely to be recovered - putting dinosaurs out of reach - scientists say it's no longer fantasy to imagine welcoming back creatures not seen for hundreds, even thousands of years. Woolly mammoths might once again roam the Siberian steppe. "Very rapidly the rest of the world is beginning to believe in miracles," says Archer. Ten years ago people would have been laughing at some of these ideas; now they're looking over each other's shoulders intently. Pieces of the puzzle ... fragments of thylacine bones. Ten years ago, plenty scoffed at his project to resurrect the thylacine using DNA taken from century-old museum specimens. Working with just fragments of DNA, Archer's team successfully extracted intact genes - a small but crucial first step in the long road towards reconstructing the animal's entire genetic code. "Mike pushes the boundaries and we need people to do that," says Karen Firestone, the project's former geneticist. People who, when they're told something is impossible, say, 'Well, I'm going to do it.' After the Sydney-born palaeontologist left the Australian Museum in 2004 to rejoin UNSW as dean of science, the project was shelved. "To say that you would park a project like that because it was fragmented DNA was not only defeatist but ill-informed," he says with frustration. If he succeeds with the gastric-brooding frog, the thylacine remains unfinished business. The passionate Archer has the rare gift among scientists of being consumed by his research but not lost in its jargon. In 2011, he stepped down as dean to resume teaching, and last year his School of Biological, Earth and Environmental Sciences students voted him their favourite lecturer. Hopped off ... a gastric-brooding frog, currently extinct. Illustration by Peter Schouten. It's a long way from his solitary childhood in the Appalachian Mountains in the eastern United States, where his parents - a US serviceman and left-wing writer and an Australian mother, who met in Sydney just after World War II - moved when Archer was one. His parents clashed with deeply religious locals, and the family, including Archer's two younger brothers, kept to themselves. "We were the oddballs," says Archer. Which is why I was focused on animals and the natural world. I didn't find people comfortable. At age 11, he discovered fossils in boulders around his home. His mother let him have a room in which he could keep them. His path was set. High-school classmate Richard Cafiero recalls an intense, bookish boy unimpressed by the local obsessions of baseball and hunting. Above all, says Cafiero, his friend was tenacious - "If Mike was going to do something, he was going to stay with it." At 14, Archer missed a student-exchange trip after refusing to declare a religion on his school form (he still delights in debating creationists). But that same year he caught the train to New York City to stay with his grandmother. He took two suitcases crammed with fossils he'd found and walked from the station to the American Museum of Natural History. At the front desk he asked if he could show them to someone. A man led him along halls lined with wooden cabinets full of curios. "That was the first installation in my brain of the beautiful smell of an old museum," he says. His guide, the late curator of invertebrates Norman D. Newell, identified his fossils for him, then and on subsequent visits. Archer is still struck by that generosity. "He had the attitude that I've adopted all through my life - that your most important audience is kids," he says. At his rambling home in Sydney's eastern suburbs, where he lives with his partner Sue Hand, a fellow palaeontologist at UNSW, and their two daughters, large cabinets display his favourite childhood finds. "I can forget a human face in five seconds, but every fossil I've ever seen is locked in my memory," he says over a bowl of fresh mango, as his pet cockatiels chatter nearby. He shows off his nature strip, planted with natives, apologising for one exotic tree. "I like the fall colours," he shrugs. But despite a lingering American accent, and a prized collection of banjos, Archer's great passion is Australia and its creatures - dead or alive. Since returning in 1967 as a Princeton graduate to join the Western Australian Museum, Archer has spent his career documenting Australia's prehistoric fossil record, mostly at the Riversleigh World Heritage fossil site in Queensland. He has kept quolls, swamp wallabies and sugar gliders as pets (he argues that everyone should) and used to attend university meetings with a cockatiel on one shoulder. It also went with him to the local shops, until it embarrassed his children too much. For Archer, the catastrophic role humans have played in wiping out so many species makes pursuing de-extinction an obligation: "It's up to us to stop screwing up the world." He teaches his students to think of the world's biodiversity as an ailing tree constantly being robbed of branches as species vanish. Which is why, after the thylacine project stalled, he soon began searching for another candidate. "I don't think Mike was ever taught to sit quietly on the sidelines," says Hand. When an old friend, Adelaide University frog specialist Associate Professor Mike Tyler, mentioned he had specimens of the extinct gastric-brooding frog squirrelled away in a lab freezer, Archer was thrilled. "We want special animals back," he says. If you bring this frog back, you bring a whole family of genetic diversity back into the world. Rheobatrachus silus (R. silus) may have been dull-coloured and covered in slime, but it was very special. Unlike any other animal on the planet, females swallowed their fertilised eggs, shutting down their stomach's acid production so their offspring could develop, before regurgitating baby frogs. Chanced upon in the 1970s in Queensland rainforests, both R. silus and another closely related species of gastric-brooding frog, R. vitellinus, were officially extinct by 1985, most likely killed off by a human-spread fungal disease which has decimated frog species worldwide. With the specimens and $100,000 from supporters including Dick Smith secured, Archer began assembling a team. Victorian reproductive biologist Andrew French was working on cloning stud rams when he met Archer through a colleague. With French and fellow reproductive biologist Jitong Guo on board, Archer based the project at the University of Newcastle, where frog experts Professor Michael Mahony, and John and Simon Clulow, run a research laboratory. French was attracted by Archer's enthusiasm, as much as by the prospect of working with ancient DNA. "And the cells looked very good," he says. The six-man team began work quietly in 2007, keen to avoid the huge public pressure generated by the highly publicised thylacine project, and keeping the frog's identity secret. What makes their progress even more impressive is that since then, the team has had less than two months all up in the laboratory. Because somatic-cell nuclear transfer, or cloning, works best with high-quality, fresh donor eggs, the team gets just one week each summer to work together in the laboratory - when the distantly related great barred frog prepares to breed. It has been laborious and difficult work. An early hurdle was to find a way of penetrating the thick jelly coating the great barred frog donor eggs (which had had its own DNA inactivated by UV light) so the R. silus DNA could be injected. For a while, nothing worked - not even when Archer impulsively put eggs in his mouth, hoping saliva might dissolve it. "I had a mouthful of slimy frog eggs at the start, and a mouthful of them at the finish," he rues. The team now gently teases the jelly off each egg under a microscope, using small forceps designed for watch-making. "It makes for long days and sore eyes," laughs French. February 15 this year was one such day. French had spent hours injecting a Lazarus cell smaller than a pin head into a precise point in around 150 donor eggs, themselves each just two millimetres wide. Suddenly the normally reserved Guo started yelling, and his colleagues rushed over to watch as one egg after another began to divide. After a moment of stunned silence, Archer recalls, the team leapt around the room. Jitong looked like someone had just given him a huge birthday cake. It's a decade since scientists in Spain produced the first cloned extinct animal with the birth of a bucardo, a species similar to a wild goat. When the last bucardo in the wild died in 2000, scientists began implanting its DNA in host eggs. A calf was born, though it died soon after birth from lung defects. What makes his team's creation of embryos ground-breaking, says Archer, is that "what we are doing is hauling out ancient tissues from a completely extinct species that has been gone for 40 years." Having confirmed the embryos contain R. silus DNA, the team's next challenge is coaxing them beyond the crucial stage known as gastrulation, when the embryo's thousands of cells start to specialise into various tissues. Parallel experiments with DNA from living frogs have hit the same snag. Archer, characteristically, is unfazed. "It's just the next speed bump in the road, and we're used to getting over speed bumps," he says. We don't know quite what we have to do - but we'll find a way. He expects a series of hurdles - perhaps, for example, the womb-like conditions of the gastric-brooding frog's stomach will have to be simulated to create tadpoles. "I wouldn't for a minute presume we can't do that," Archer says. French attributes much of the team's progress to that faith. "I have worked with other professors who sit in their office and just hope the work gets done," he says. Mike gives us the momentum and the belief that this will work. He's the glue that keeps us all focused. But while the scientific power to undo extinction may be within reach, should we use it? Some conservationists argue reviving species is pointless if there's no habitat left for them to return to. It's unlikely, for instance, that the gastric-brooding frog could be "re-wilded" given the threat of fungal disease in its original home. Even so, Archer says, "I'd rather have that genome and that biological diversity available, even if it's in a breeding facility and can't be put back in the wild at the moment, because further down the road we can probably put that environment back together again when we get smart enough about how to do that." President of the Australian Conservation Foundation, Professor Ian Lowe, agrees: "Even if you can only sustain a species in a zoo-type situation, we are the poorer if they are not around. Having tigers in zoos is better than not having them at all. Conservationist Jim Thomas has been working with remote villages in northern Papua New Guinea for a decade to save the tenkile, an endangered tree kangaroo. To him, de-extinction is "putting the cart before the horse. There's so much on the ground that has to be done now. Atticus Fleming, chief executive of the Australian Wildlife Conservancy, whose 23 sanctuaries cover three million hectares and are home to some of the nation's most threatened species, concurs. "We know what needs to be done to save species like the numbat, greater bilby and Gouldian finch - feral animal control and better fire management," he says. There is no excuse. To even contemplate the use of this sort of technology to save living species would be a national embarrassment. We can save these animals without resorting to technology. Robert Lanza, chief executive of California-based Advanced Cell Technology, argues that while habitat preservation is crucial, genetic technology can be a powerful new partner in conservation efforts. It doesn't make much sense to spend all our effort on habitat protection if there are no animals left. Having cloned several endangered animals, he's so impressed by the Lazarus team's work he's begun collaborating with them. The value of bio-banking the genes of endangered species for future use is enormous, says French: "We can have many thousands of frog species in one liquid nitrogen container about the size of a big home fridge." But would de-extinction technology be a wonderful insurance policy or a game-changer for conservation, with less money and attention directed towards saving living species? Ian Lowe thinks the former. "Suppose you could see a thylacine at Taronga Zoo next week - people would be queuing around the block to marvel at it," he says. I think it's more likely to stimulate interest in nature than promote a cynical attitude that it doesn't matter if we lose a species here or there. After all, he says, "we are losing so much biodiversity so fast that anything we can do to slow that down is a good thing." But would a cloned thylacine instinctively know how to hunt? Would a gastric-brooding frog bred in a laboratory know how to be of its kind? Oliver Ryder, director of genetics at the San Diego Zoo, which is part of the global Genome 10K project aiming to store the genomes of 10,000 vertebrate species, says that's unclear. Like many in the audience in Washington, Ryder was astounded by the Lazarus Project's achievements. But he cautions that bringing back species on a large scale remains extremely difficult. Resurrecting an individual animal will not automatically restore the gene pool of that species, with its enormous range of genetic variations - even in humans the importance of such variations between individuals is poorly understood. Without its gene pool, which gives a species its vibrancy and resilience, "you are bringing back a thin shadow," says Ryder. He believes that, ultimately, de-extinction technology's greatest impact may be to raise awareness of how much easier it is to protect what we still have. There are many unknowns surrounding the quest for de-extinction. "All I'm sure of," says Mike Archer, "is that it's going to happen a lot quicker than most people presume." If he's right, the most tantalising question may be: who decides what comes back? On a crowded shelf in Archer's office sits the skull of a carnivorous marsupial lion, which hunted across Australia around 40,000 years ago, carrying its young in its pouch. Would he resurrect these formidable predators, with their teeth like bolt cutters, given the chance? He pauses. That's a real hard one. We've wanted to know so much about these animals that we can't possibly find out without studying a live one," he says. Given how long ago the lion vanished, it's unlikely its DNA could ever be recovered. Then again, Archer quickly adds, "Never say never."