14 DAY TRIAL // In the Jurassic Park movie the dinosaurs were re-created starting with some DNA trapped in amber. A somewhat similar technique has been developed by scientists at the Weizmann Institute of Science. They have found a new place to look for well-preserved, uncontaminated ancient DNA in fossil bones and how to retrieve the information.
Fossil DNA is often impossible to interpret because it is either damaged or contaminated by modern DNA. However, in 1986 Prof. Steve Weiner of the Institute's Structural Biology Department discovered the existence of crystal clusters in fresh bones. These crystals have embedded DNA and can potentially preserve it unaffected from external factors for a very long time.
Now, almost 20 years later, Weiner and his colleague Michal Salamon have looked for such crystal structures in fossil bones. They reason that these might contain preserved ancient DNA. Ancient DNA is a potential source of information on the evolution, population dynamics, migrations, diets and diseases of animals and humans, but in order to be reliable it has to be uncontaminated. The DNA trapped in these crystals is exactly what researchers have been looking for.
Working in collaboration with Profs. Baruch Arensburg, from Tel Aviv University, and Noreen Tuross, from Harvard University, Weiner and Salamon have managed to devise a technique of extracting the DNA from these crystals and assuring they are uncontaminated.
They have used a substance called sodium hypochlorite to treat the bones. This substance removes all traces of organic matter, but nevertheless, the organic material embedded in the clusters of crystals remains intact and unaffected. This way they reduced the possibility of contamination with modern DNA.
The scientists found that DNA fragments extracted from these crystal aggregates were better preserved and longer than the DNA fragments from untreated bones. The crystal aggregates act as a "privileged niche in fossil bone," protecting the DNA from hostile environments and leaving it relatively undamaged over time. The team's findings suggest that the DNA in these aggregates should be preferred, whenever possible, over DNA from untreated bone.
This method holds much promise for the future analysis of ancient DNA in bones in yielding more reliable and authentic results than has previously been possible.