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Posted by on Oct 11, 2012 in Science |

DNA has a half life of 521 years

DNA has a half life of 521 years

Can dinosaurs back to Earth recovering their genetic material? Most of the scientific community can not see this option. Maybe from now on, it is even less possible, but nobody knew exactly half-life was DNA. A new study of fossils in New Zealand opens the window to determine the time in which the genetic material begins to crumble. has a of 521 years .

When a cell dies, the enzymes start to break bonds between the nucleotides that form the backbone of DNA, is the time that microorganisms accelerate decomposition. Eventually, the reactions with water are believed responsible for the degradation of most of the elements. Groundwater, pervasive, causes the DNA in samples of bones buried degrade at a certain rate.

The hardest thing so far has been to determine the rate (time). The reason is that it is difficult to find large aggregates containing DNA with the common fossil that meaningful comparisons. Even worse, variable environmental conditions such as temperature, degree of oxygenation microbial attack or alter the speed of the decomposition process.

The study by a team of paleontologists from Murdoch University in Australia led by Morten Allentoft might have found the key. Scientists examined 158 DNA containing bones of an extinct species of bird called the moa in southern New Zealand. Bones dating from between 600 and 8,000 years old and had been recovered from three sites within 5 km, with identical storage conditions at a temperature of 13.1° C.

Through comparing the age of the specimens and the degree of degradation of DNA, researchers calculated half life of DNA, a figure of 521 years. Stated another way, after 521 years, half the nucleotides and linkages between the backbone of a sample would have broken, after another 521 years, half of the remaining elements would be gone. According Allentoft:

The DNA is degraded to a certain speed and therefore make sense to talk of a half life. These 521 years are 400 times more than expected from laboratory experiments at similar temperatures

According to researchers, it can be predicted that even a bone to an ideal storage temperature (about -5° C), all elements of the DNA would be destroyed after a maximum of 6.8 million years. The DNA should be readable long before (it says 1.5 million years ago), when the remaining strands would be too short to provide meaningful information.

Returning to the possibility that samples dinosaurs could survive until today, Simon Ho, one of the researchers, indicates that:

This confirms the widespread suspicion that the old complaints about the DNA of dinosaurs and ancient insects are incorrect. However, although these 6.8 million years serving to destroy all DNA elements are near the age of a dinosaur bone, I think we might be able to break the record for the oldest DNA sequence, a figure which is currently around half a million years.

Yet these 521 years of average life will be subject to further studies. Scientists will have to see if the results can be reproduced in different environments such as a cave, soil chemistry or even the time of year when the animals died.

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