QUOTE (anarkhy @ May 12 2008, 09:03 PM)

Cant imagine what you expect about alien life. It certainly will have cells and some way to keep the information inside these cells, so they must have dna, not like ours, but they need to have something very similar.
I do think the chances of life on another planet are very extremely rare, but if exist, its pretty much closer to what we have on earth.
You never know, DNA might have been an unbelievably lucky fluke here on Earth, just like all the other major advances in the evolution of life. Maybe they went a few steps further beyond DNA or they have something completely different which we could never have pictured, that might have arisen in the primordial soup but failed to gain precedence over DNA.
However, we can assume that because the elements that make us up are very common in the universe, life elsewhere is likely to be similiar in that way, and they'd still be influenced by natural selection. Beyond that there isn't much we can really know.