[Southack]

"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." - Ha Ha Thats Very Logical

No, Fish don't have endotoxin recognition and signaling. Coral have it with TLR. Humans have it with TLR-4.

Fish have TLR-4, but it does something entirely different.

That's not a gradual, evolutionary, smooth step to smooth step process.

It is, however, what one sees in modern computer programming with code re-use of portions of old programs used in (or slightly modified for) new software.

[Ha Ha Thats Very Logical]

No, Fish don't have endotoxin recognition and signaling.

Hm. the article I linked to before certainly seems to say that fish have endotoxin recognition: "Our analysis also suggests that beta-2 integrins...may play a primary role in the LPS recognition by the piscine immune system."

Further in the same article, it says "Recently, Roach and colleagues suggested that Fugu TLR23 may participate in LPS recognition which may compensate for the loss of TLR4 in this species" and "Our analysis also suggests that alternative signaling receptors such as beta-2 integrins may play a primary role in the activation of piscine leukocytes by LPS."

Doesn't that sound to you like fish have an endotoxin recognition system, just one that doesn't use TLR-4? I don't think computer programmers usually take a piece of perfectly good code, ignore it (or use it for something else), and "compensate" for the loss of that code with an alternative.