The 1993 movie "Jurassic Park" wasn't the first film to show dinosaurs in the modern world. But it did a good job of bringing the idea of cloning dinosaurs into popular culture. It portrayed dinosaur cloning in a way that made sense to a lot of people, and it was a blockbuster, making more than $900 million worldwide [source: New York Times].
Dinosaur Image Gallery
"Jurassic Park" built on the idea of extracting DNA from the bellies of mosquitoes preserved in amber. While this might seem possible at first glance, it's highly unlikely that scientists could find usable dinosaur DNA in mosquito fossils. Scientists would need a very specific specimen -- a female mosquito that had consumed lots of dinosaur blood immediately before landing in tree resin. Since fossilization in amber is a relatively rare event, the chances of this happening are pretty small.
The lack of possible specimens isn't the only problem. Most insect fossils found in amber are also too young to contain dinosaur blood -- dinosaurs were extinct by the time the insects became trapped. Many insects decay from the inside out after they're trapped, leaving nothing inside for scientists to try to extract. Finally, the sample would have to be very dry, since DNA can break down quickly in the presence of water.
But if researchers did find a perfectly preserved mosquito with a body full of dinosaur blood, retrieving its DNA would still be difficult. The blood with the dinosaur DNA would be surrounded by the body of an insect, which has its own DNA. There could also be DNA from other cells trapped in the amber, which could contaminate the sample. Then, of course, there's the DNA in the laboratory itself -- and in the body of the scientist doing the extraction.
The fictional scientists in "Jurassic Park" try to get around these difficulties by combining dinosaur DNA with frog DNA. But this would be like trying to assemble a jigsaw puzzle using billions of pieces that come from two different puzzles. Plus, frogs might not be the best candidates for providing replacement DNA. Today, one of the most prevalent theories about the fate of the dinosaurs is that some evolved into birds, not frogs.
On top of all that, the most common form of cloning used on animals today involves nuclear transfer. Scientists put the nucleus of one cell into a second cell of the same species after destroying the second cell's nucleus. There are no dinosaur cells or dinosaur eggs that could host new set of DNA. Researchers would have to find a different way to let the DNA grow into a living dinosaur.
So the "Jurassic Park" method is out -- but are there other ways to bring dinosaurs to life? Read on to explore the possible answers.
Mammoths and Dinosaur Cloning
Besides using DNA from insects trapped in amber, there are several theories about how scientists might clone dinosaurs. One involves finding DNA specimens in fossilized bones instead of in the bodies of insects. The problem with this idea is that DNA is a complex, delicate structure. The process of fossilization involves replacing the organic tissue in an animal's bones with minerals. This effectively destroys the cells that may contain DNA.
However, one team of paleontologists has discovered what appears to be soft tissue in the bones of a Tyrannosaurus rex. It was a discovery no one could have predicted -- until that point, scientists thought all soft tissue was destroyed in the fossil process. However, the research team has not yet isolated any DNA from the soft-tissue samples. While the discovery doesn't necessarily guarantee that researchers will ever find intact DNA in fossils, it makes the idea more likely than it was just a few years ago.
Another appealing idea is that researchers could sequence the DNA of dinosaurs and recreate the necessary DNA strands. At this point, this isn't possible. The sequencing of the human genome, for example, took 13 years to complete, and the final product wasn't something researchers could use to clone people. Reconstructing complete strands of dinosaur DNA would require technology far beyond what exists today.
That leaves what may be the next best thing to cloning dinosaurs -- cloning extinct mammals, like mammoths. Mammoth fossils are significantly younger than dinosaur fossils. They're only about 30,000 years old. This difference in age gives the DNA much less time to decompose. But a mammoth cloning project would still require a perfectly preserved specimen. The mammoth's tissue couldn't have gone through cycles of freezing and thawing or been preserved at extremely low temperatures that could damage the DNA. Yet, the idea of piecing together this evidence to get an idea of mammoth genes isn't completely unreasonable. In 2005, one research team reported that it had sequenced part of the mammoth genome.
A second option for bringing mammals to life could be to use fossilized sperm to inseminate the eggs of a related mammal. The resulting animal would be a hybrid, with only half its genetic code from its male mammoth parent. A project to do exactly that was proposed by a Japanese research team in 2006 [source: Times Online].
These advances in paleontology and genetic technology have made the idea of cloning dinosaurs just a little more probable sometime in the far future. But it's still not at all likely, especially not in our lifetimes.
Want to learn more about cloning, dinosaurs and other topics? You'll find lots of information on the next page.
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More Great Links
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- Inman, Mason. "Mammoths to Return? DNA Advances Spur Resurrection Debate. " ational Geographic News. 6/25/2007 (1/3/2008) http://news.nationalgeographic.com/news/2007/06/070625-dna-resurrection.html
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- San Diego Natural History Museum. "Science of 'Jurassic Park' Frequently Asked Questions." (1/3/2008) http://www.sdnhm.org/research/paleontology/jp_qanda.html
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