My point is that creationists cannot point to any one thing that defines a dog as a dog because the moment they do they provide a mechanism for change.
(1) The genome specifies all of the criteria by which we judge the resulting animal a dog.
(2) The genome can change under selectional pressures.
(3) No region of the genome is protected from change.
From 1, 2, & 3, it follows that a dog lineage can slowly move away from what we would classify as "dogs", given enough time.
