It is only because you have assumed 'common descent' that you think genetic markers mean anything.
'Assume' is not the right word here. Anything that is based on evidence is by definition not 'assumed'.
And I'll guess you know that the Discovery Institute (Behe, et al) excepts common descent? And that DI is the ID preeminent, world renowned in certain circles, ID think tank.
So where's the evidence the universe is 6000 years or so old?
excepts = accepts
Sorry, just because it is 'based' on evidence doesn't mean that it isn't 'assumed'.
Except in the evolutionary dictionary, that is, where it is a requirement.
That's part of the deception.
And Behe 'excepts' common descent?
Actually, there is no evidence that the universe is not 6,000 years old. If you can tell the difference between evidence and intepretation, of course. I'm betting that you can't.