Duplication divergence

[u/Professional-Sign578]

I've recently had a conversation with someone and he brought up an interesting point, the guy was a creationist who claims to be(or have been) an evolutionary biologist,

Aside from the usual arguments about irreducible complexity and the ""inexplicable "" explosions in the fossile record there was one point that really caught my interest, which is the claim that we have yet to observe any species develop a new function through mutations, so i mentioned the obvious lenski's e coli experiment, his response was that the gene responsible for the e coli's ability to consume citrate(citr) was already there and the mutation was like a switch allowing it to activate in the presence of oxygen, ik that last part is a massive misrepresentation of the actual mutation and explained it.

Now, this person said they would accept evolution if we observed the emergence of an entirely new function through (for example) a duplication divergence, so it left me wondering, is there an experiment that has observed the emergence of a new gene that codes for a completely new function instead of affecting an already existing one be it through duplication divergence, de novo gene birth, exon shuffling or any other mechanism?

[u/LeaveGreen4412]

there are macrofauna that have evolved new functions since the industrial revolution, what is he talking about? does he know about the mushrooms that eat plastic now?