If you want to do it properly, you're going to have to look at the information. Fur colour is not the information.
If you would read a bit more carefully, I said the message was how to make the fur color, not the fur itself.
Let me try to itemize step by step:
1 - If we start with brown-fur boders, and a random DNA change gives them white fur, you say that will necessarily cause a degradation in their genome. That is, the genome of white-fur boders will be degraded from that of the brown-fur boders they mutated from.
2 - On the example when Yorzhik chimed (post 247) in he said if the "white fur" DNA returned to “brown fur” DNA it would bring them back to where they started – no genome degradation. To that you said “Exactly” (post 250).
3 - Now consider a slightly modified scenario in which there had never been brown fur boders, only white ones, with DNA and a genome identical to the white ones mentioned in step 2 above. If they experience the DNA change that gives brown fur, their biological makeup will be identical to what the original brown-furred ones would have been.
4 – In this modified scenario, since boders started with white fur DNA, and there was a random change to it which resulted in brown fur, you say information theory dictates that there is a genome degradation.
5 – In both cases we end up with genetically identical brown fur boders, yet the second set of brown-fur boders have undergone genome degradation as a result of the random change to their original white-fur DNA. But as shown in step 1, white fur boders already have a degraded genome.
6 – How can the degradation of already degraded white fur boders (case 2) end up with the same genome integrity as boders which have no genome degradation (case 1)?