Hey, that's a sensible idea. I was going to suggest the stretch of DNA they looked at seems to have been resposible for the development of four limbs. That's why it's conservative. Any mutations there would lead to such things as five limbs, deformed limbs etc. The article doesn't mention whether they compared the section to other primates. We know primates have relatively unspecialised limbs and so we would expect the region responsible would be primitive. The same stretch of DNA in other mammals would presumably be more different. Does that make sense?
They said the region was an 100% match with every mammal they checked. The article specifically mentions the segment is identical between humans, rats, and mice.
http://www.ncbi.nlm.nih.gov/Genomes/ lists the animal genomes they have in the genbank database. This includes the chimpanzee.
Most of what you say makes sense, except I don't believe the chimpanzee would necessarily diverge. They're limbs are still quite important, even if 'unspecialized.' (Not sure what criteria you use in that judgement, but okay.)
The might, for example, look at frog, chicken, a few lizards and a snake. We don't have those genomes yet - at least not in genbank. If this is conserved because it has to do with limbs, then we might expect it to be slightly different for snakes - and possibly chickens.
