It might doom the idea of common descent, but not necessarily that of evolution in general. Or it might simply push the time for a common descendant back to some hypothesized earlier stratum.
The real weakness of the ideas that "it ALL happened this way" (be it via evolution or creation) is that both sides ignore obvious facts that inhabit the middle ground where both approaches can work in tandem. We can observe the effects of genetics on inherited traits. We can likewise demonstrate that intelligent designers can and do have the capability to affect genetic outcomes.
Interestingly, it is the so-called "scientific" types who (as on this thread) tend to have the most dogmatic attachment to their "ALL".
No I think that scientists on this thread are arguing that ideas such as intervention by an intelligent designer are not science, not that they couldn't possibly have occurred. Furthermore, I think many are waiting to see evidence that an intelligent intervention did in fact occur during the process of devolpment from single-celled organisms to modern life. If such evidence is given, it will be considered. This means positive evidence, not argument from ignorance or statements such as "you can't prove that there's no design." You need to show that there is design.