Basically just time scale. When people talk about DNA having degraded too much, it's generally in the context of bringing back dinosaurs. Dinosaurs went extin

Basically just time scale. When people talk about DNA having degraded too much, it's generally in the context of bringing back dinosaurs. Dinosaurs went extinct about 65 million years ago, which is (obviously) much longer than 30,000. Until recently it was thought that DNA degraded more quickly, indeed making it un-viable after only a few thousand years, but a relatively recent study put the half life of DNA at 521 years, meaning that it would take several million years to degrade fully, under ideal conditions.[1] Therefore, bringing back animals like the woolly mammoth should be quite feasible, but probably not dinosaurs. [1] http://www.livescience.com/23861-fossil-dna-half-life.html http://www.livescience.com/23861-fossil-dna-half-life.html