How to Make a Woolly Mammoth Should Scientists Bring Extinct

BIOLOGY: Genetics // CHEMISTRY: Biochemistry // // EARTH SCIENCE: environment PHYSICS: technology ntil the 1980s, Australia was home natural disasters, disease outbreaks, or to a very odd amphibian: the climate change. WATCH gastric-brooding frog. The strange “All of these ‘de-extinction’ projects are A VIDEO thing about this frog was that the focused on trying to increase the complexity ONLINE www.scholastic.com female laid her eggs in water, and and diversity of the natural world,” says Mike /scienceworld Uonce the male fertilized them, she swallowed Archer, a paleontologist at the University the eggs whole. Her tadpoles grew inside of New South Wales in Australia. Archer is 4 BONUS her stomach. When the baby frogs were fully leading the team that’s trying to bring back SKILLS developed, the mother burped them out of the gastric-brooding frog. SHEETS her mouth! When Archer set out to revive the frog www.scholastic.com /scienceworld FROM This strange species fascinated scientists. 5 years ago, the first thing he needed was an BACK But soon after researchers discovered gastric- intact nucleus from one of its cells. Nuclei brooding frogs in the early 1980s, a fungal contain an organism’s DNA. This chemical infection wiped all of them out. The species carries the hereditary information that became extinct. determines an animal’s traits. Now, three decades later, the gastric- Scientists have been using nuclei from brooding frog may come back to life. living animals to create clones, or genetically Scientists are trying to use biotechnology— identical copies, of those animals for many THE the artificial manipulation of living things—to years (see Cloning Timeline, p. 10). But DEAD resurrect the baby-burping frog, as well as when an animal dies, its cells decompose should scientists bring extinct species back to life? species that have been extinct much longer. and the DNA inside its nuclei begins to break “Just imagine looking at a saber-toothed cat, or a woolly mammoth, or a giant ground Dna sloth—things our ancestors saw,” says Hank eGG transFer: Under Greely, a bioethicist at Stanford University in a microscope, a researcher injects California. “That’s plausible now.” an egg with genetic material to create a REVIVING A SPECIES clone. Why bring back extinct species? One reason is to increase biodiversity, which has declined in many areas as species die off. When an ecosystem has a wide variety of a pipette injecting a pipette holding the m) genetic material O animals and plants, there’s a better chance egg in place tt BO that at least some of them will survive k ( OC t s C hi P a OGR How to Make a WOOLLY MammotH al Ge scientists may be able to use a frozen cell from a mammoth that’s been dead for thousands of years to bring the ON species back from extinction. an elephant—the mammoth’s closest living relative—would carry the baby clone. tista,/Nati P mammoth elephant nUcleUs eGG G Ba O d N a RN tock GG); Fe s e ( e raphic OURC G s Remove the Chemically Place the egg if the e NC 2 3 4 5 ie isolate the nucleus from the or electri- in the uterus pregnancy C s 1 ational Geo ational nucleus of a egg of an elephant cally stimulate of an elephant. it is successful, the n viable mammoth cell and replace it with the the cell to make will take almost two elephant gives birth e Psaila/ PP from a frozen carcass. mammoth nucleus. it begin dividing. years to develop. to a baby mammoth. Jon Foster/ Phili 8 SEPTEMBER 2, 2013 WWW.SCHOLASTIC.COM/SCIENCEWORLD 9 something else: inserting buried mammoth fossils scientists working on the cell nucleus of the and, in a few cases, the these projects should extinct frog into the egg of frigid conditions have be very careful. Many of another species. He started helped preserve some the environments that collecting eggs laid by great DNA. A group of South extinct species once barred frogs, a common Korean and Russian inhabited have changed species in Australia. researchers hopes to use since they lived there, Over the next few years, this material to bring he says. If a long-gone Archer’s team injected thou- mammoths back to life species is reintroduced, sands of great barred frog one day (see How to it could become an eggs with gastric-brooding Make a Woolly cominG Back? the gastric- invasive species that brooding frog, now extinct, frog nuclei. None of them Mammoth, p. 9). birthed babies through its mouth. upsets the current grew. But the researchers Ben Novak, a biolo- ecosystem. kept trying and adjusting gist at the University Gone For noW: Some conservation- their technique. of California, Santa passenger pigeons ists also worry that if were hunted to Finally, about two years Cruz, wants to use extinction in the 1800s. scientists can bring ago, one of the eggs started genetic techniques to extinct animals back, dividing. When Archer tested bring back the extinct no one will care about the growing ball of cells, or passenger pigeon. These keeping endangered embryo, he found gastric- sleek, gray-blue birds species from becoming brooding frog DNA inside. used to flock over the extinct in the first place. “That told us that the s (2009) Northeastern U.S. in “If this were to ON mammoth down. This makes cloning an extinct species extinct animal’s DNA was driving the devel- mm groups of a billion or undercut efforts to mUmmY: this baby O mammoth’s body, much harder than cloning a living one. opment of a new frog,” he says. more. But by the late conserve currently discovered under Luckily, back in the 1970s, another 1800s, they had been existing species, that ikimedia C CORE permafrost in w siberia in 2007, scientist had frozen some gastric-brooding DE-EXTINCTION PLANS hunted to extinction by trappers who sold would be a tragedy,” says Greely. QUESTION still had some Dna frog tissue and saved it. Archer examined So far, none of the eggs have grown past (2003); them for people to eat. Bringing them back Archer doesn’t think that will happen. In inside. OO cells from the frozen sample and was excited the embryo stage into baby frogs. Archer and Z would help restore biodiversity to the forest fact, he says, the cloning techniques scientists should scientists GO ie d to find that their nuclei appeared intact. his colleagues aren’t sure why. But if they can ecosystems in which they lived, says Novak. develop to bring back extinct species could try to bring back N a The next step was to find an egg. In solve that problem, says Archer, “I’m hopeful s be used to breed endangered animals too. extinct species? traditional cloning, scientists take an egg that within a few years we should have this ETHICAL CONCERNS Many of the species scientists want to Cite evidence s (2001); s (2001); R from the article cell from a female of the same species and frog back.” te Technology may have made it possible bring back became extinct because people U remove its nucleus. Then they replace it with Archer’s attempt is the farthest along, but to bring back extinct species. But does that hunted them or ruined their habitats, argues to support your the nucleus of a regular cell from the body other teams of scientists want to use similar mean it’s a good idea? Archer. Humans even helped spread the opinion. R New/Re ST of the individual they want to clone. When techniques to bring back other extinct ); Hank Greely, the Stanford bioethicist, fungus that killed off gastric-brooding frogs. ON e G the egg starts to divide, the new cells contain species, like the woolly mammoth. These i studies the ethical implications of technolo- “They shouldn’t be gone, and we did s (1996) P R ( e copies of the donor animal’s DNA. hairy relatives of elephants roamed the frozen te gies like cloning. He thinks de-extinction it,” says Archer. “I think we have a moral U /Re OURC k But no one had saved any gastric-brooding tundra of Siberia until they died out about s has many potential benefits, including responsibility to try to fix what we broke.” e frog eggs. That meant Archer had to try 5,000 years ago. Scientists have found many NC helping ecosystems recover. But Greely says —Mara Grunbaum hell U ie C C it s m k/ J FF coc ay l e org k (1952); Je k (1952); cLoning OC ); Ge kst N frog hi t TIMeLine ( e scientists first cloned ); OP OURC animals more than 60 s es (t e G NC ma years ago. since then, i 1952 1996 ie 2001 2003 2009 C s breakthroughs in cloning y/ scientists create the first cloned animal—a Dolly the sheep, the first mammal cloned R Researchers clone the first domestic Cells from a dead banteng, a type of scientists report that they used frozen a FP/Getty technology have brought BR a i tadpole—by extracting a cell nucleus from using the body cell of an adult animal, is l cat. the kitten is named cc, for “Copy wild asian cattle, produce a healthy cells to clone the bucardo, an extinct O sti/ them closer to being able t O O a developing embryo and inserting it into born in scotland. dolly becomes famous v Cat.” some companies begin offering cloned calf—raising hope that cloning spanish goat. But the clone, born with O Ph to revive extinct species.

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