M6 Discussion: Cloning Dinausaurs? In 1997, Scottish researchers captured newspa
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Question
M6 Discussion: Cloning Dinausaurs?
In 1997, Scottish researchers captured newspaper headlines when they announced the birth of Dolly, a lamb cloned from an adult sheep by nuclear transplantation. These researchers cultured mammary (nuclear-donor) cells in a nutrient-poor medium and then fused these cells with enucleated sheep eggs. The resulting diploid cells divided to form early embryos, which were implanted into surrogate mothers. Out of several hundred implanted embryos, one successfully completed normal development, and Dolly was born. Later analyses showed that Dolly’s chromosomal DNA was identical to that of the nucleus donor.
Numerous other animals have been cloned thus far. In fact, the science fiction plot of Jurassic Park, revolves around a theme park showcasing cloned dinosaurs. These dinosaurs were cloned from DNA found in mosquitoes that had sucked dinosaur blood and had been trapped and preserved in amber.
Do you think it is possible to recreate dinosaurs by this technique? In this discussion assignment, tell us (in 250-300 words) why you think so.
NOTE: PLEASE CITE SOURCES
Explanation / Answer
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 is highly unlikely that scientists could find usable dinosaur DNA in mosquito fossils.Scientists would need a very specific specimen taht is a female mosquito that had consumed lots of dinosaur blood immediately before landing in tree resin.Since fossilisation in amber is a relatively rare event,the chances of this happening are pretty small.
The lack of possible specimens is not the only problem but most insect fossils found in amber are also too young to contain dinosaur blood and dinosaurs were extinct by the time the insects became trapped.Many insects decay from the inside out after they are 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 there is the DNA in the laboratory itself and in the body of the scientist doing the extraction.
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.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.
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