Information Theory implies that new uses for old coding routines is due to intelligent design (or redesign), not happenstance.
We certainly see the same code used for entirely different purposes in computer programming, for instance.
Right, but here you have the same code used for a different purpose, while some *other* piece of code is used for the original purpose. If you need endotoxin recognition, why not just use the code that’s already there?
That’s why I asked what you think happened. Why, exactly, do coral, fish, and mammals all have TLR-4* but fish don’t use it for the same thing the other animals do? Do you have an explanation, or are you just trying to nitpick evolution?
(* I’m taking your word for the fact that fish have TLR-4.)