If we ever confirm life on Mars (or anywhere else for that matter), I really hope we don't find that it shares a common ancestor with life on Earth. Panspermia is cool, but two instances of abiogenesis in a single solar system? That is huge.
Here's to hoping it's life, but not as we know it.
>"I really hope we don't find that it shares a common ancestor with life on Earth". Could you give a definition here, please?
I cannot respond to you directly, but sure. When I say I hope there is not a "common ancestor" I mean that I hope life on Earth and life anywhere else we may discover it do not have "common descent" (http://en.wikipedia.org/wiki/Common_descent). That is strongly believed to be the case with all life we have encountered so far. This is also a pretty good wikipedia page about this: http://en.wikipedia.org/wiki/Last_universal_ancestor
Here's to hoping it's life, but not as we know it.