Recently I came across several examples of how genetic
information has greatly helped us understand the past. Quite
often this data is gathered in the most unexpected places.
Consider these examples. In an article published in December
2009, an international group of scientists addresses the issue
of the extinction of North American megafauna traditionally
dated some 11,000 years ago. A skeleton of a woolly mammoth on
display in a museum never fails to impress us. At the same time,
most of us would agree that it is a good thing we don’t have to
worry any more about these lumbering giants messing up our
evening commute. However, what most of us stop worrying about is
when these animals became extinct and why. Most of us, that is,
but not all of us. This is where the story of ancient DNA
retrieved from perennially frozen soil comes in. A traditional
approach to estimate when and where a species became extinct has
been to map and date the last known survivors. The thinking was
that knowing when and where the las