Uh, so? Some genes are highly conserved. Note this leads to ANOTHER prediction (and potential falsification) of common descent. Genes that are highly conserved in humans, and chickens and puffer fish should also be highly conserved in other vertebrate animals as well.
I'll guarantee though that, however highly conserved relative to other genes, no given gene is MORE similar between humans and puffer fish than between humans and chickens.
How can I guarantee that this is the case, unless evolution DOES make falsifiable predictions?
That's how unfalsifiability works. If the genes are the same, they are 'highly conserved'. If they are not the same, they aren't 'highly conserved'.
It means nothing at all.