Does Dinosaur DNA still exist? - Part II

Iron saved soft tissue in Dinosaur fossils?

The iron nanoparticles, however, may be doing more than just preserving tissues.

Despite what happens in the science fiction world of “Jurassic Park”, no dinosaur DNA has yet been found. The reason for this is that DNA is thought to have a half-life of 521 years, so what could be left after the 65 million years or so that stand between humanity and dinosaurs? But could the iron-based preservation process might allow DNA to bypass its typical half-life and last a lot longer.

To find that out, Dr Schweitzer and the team used an iron-removal compound to delicately pull iron away from the dinosaur tissues without damaging them. They then added four different stains that react only with either DNA itself, or with proteins closely associated with it in organisms other than microbes. Remarkably, in all cases, these specific stains lit up inside the ancient cells in the tissue samples. This hints that something chemically very similar to DNA can remain in a fossil and might yet be hidden precisely where it had resided during life.

As to whether any DNA strands can ever be read remains to be determined because of the complex knots that they have been tied into by the iron. But Dr Schweitzer and Dr Goodwin plan to try. Many things other than iron tie proteins into knots. One is sugar which, when exposed to tissues in high enough concentrations, can also cause abnormal bonds to form. This process damages tissues in diabetics. Some doctors suspect the process might be reversible by using drugs, like N-phenacylthiazolium bromide, that selectively cleave abnormal bonds while leaving normal ones alone. With this in mind, the researchers are considering trying some of these drugs on their dinosaur proteins to see if they can untangle them.

In the end, such tactics will not be quite as poetic as Hollywood’s notion of collecting dinosaur DNA from bloodsucking mosquitoes preserved in tree sap. But if it results in sequencing even part of the genes of a T. rex to determine more about these and other prehistoric animals, then no one is going to mind.

Source: The Economist