Has innate immunity evolved through different routes?

Invertebrate self/non-self recognition, defense responses, mating and development share innate immune serveillance and functions challenged by competition and linked to fitness. Independent evolutionary branches of immune responses may use conserved gene traits. On the other hand immunity genes may be conserved due to theie role in development. Finally, upregulation of innate immunity genes during ascidian metamorphosis supports the danger hypothesis.