The possibility of resurrecting extinct animals some day in the future may not be as far fetched as previously thought. A paper in this week's Science reports that soft tissue from a 70 million year old Tyrannosaurus Rex was found in Montana. The specimen contained blood vessels and possibly cells. Finding pieces of DNA is a long shot but remains a remote possibility.
In fact, extracting DNA from extinct animals is becomng more common A recent article in PLOS Biology reviews the many ways that ancient DNA has been used to ask questions about population genetics in the past. It is probably not surprising that there are signs that our current descriptions of the evolutionary process based on the fossil record and modern DNA is far too simple. Since DNA is a fragile molecule, most studies are limited to DNA less than 60,000 years old. However, that's still old enough to get some interesting information. The hardest thing to prove is that the sample is not contaminated with modern DNA.