There's enough frontloaded to allow wide variation within species so that they can adapt to changes within their environment so that they can stand a better chance for survival. That doesn't imply by default that enough variation can occur to give rise to entirely new species.
That conclusion is extrapolated from the fossil record. The evidence can demonstrate relationships just fine, but not guarantee common descent where some mammalian ancestor produces ALL the mammals we see today.
A good way to demonstrate this would be to make some predictions about the plasticity of some specific genomes. Like actual hypothesis formation and testing.
I'm just soliciting comments on the possibilities.
I don't think we've got nearly enough information to be saying anything definitive at this point, but if you've got something to suggest where the limits and boundaries can be drawn, put it up for consideration.