[RightWingNilla]

The problem is, the DNA evidence just shows that all life on earth is related. It doesn't require descent from common ancestors. Could be aliens. Or devas. Or angels. Or Chuthulu. Or whatever.

Well the way I see it the two major possibilities are:

1. Common descent from a single ancestor, or

2. The intelligent designer went to quite a bit of trouble to make it look like it.

The relatedness between species extends to arbitrary codon usage for specific amino acids (Is there something special about 'UGG' that is should encode for tryptophan in every organism?), shared errors and other oddities.

[Aric2000]

Wow, for a thread that has been pointed to to let off steam, it sure looks civil to me.

What's wrong with this picture? Oh, that's right, someone is missing from the debate, let's not ping him, I like the atmosphere here.

[dark_lord]

Well the way I see it the two major possibilities are: 1. Common descent from a single ancestor, or 2. The intelligent designer went to quite a bit of trouble to make it look like it. The relatedness between species extends to arbitrary codon usage for specific amino acids (Is there something special about 'UGG' that is should encode for tryptophan in every organism?), shared errors and other oddities.

Have you ever designed programs and written software? If so you know that you "borrow" extensively from previous designs where appropriate, and absolutely reuse code wherever you can. Why write something from scratch if you can take something that does 70% of what you need and re-work it? So you end up doing a bunch of copy&paste. Not to mention that the object oriented model is designed to enable this through the concept of inheritance.

So -- in fact your point is equally applicable to intelligent design as it is to evolution. Except for evolution, it must imply a common ancestor, whereas with intelligent design, it just implies "mostly" common ancestry.