Feathers, which are the most complex integumental structures known in the animal kingdom, without doubt required coordinated changes in numerous genes.
Explaining the origin of complex phenotypic novelty is the million-dollar question in evolutionary biology.
Cutting to the heart of even a very big subject is possible and desirable and important. Here’s an attempt an answer.
If cichlid evolution is a central paradigm in evolutionary biology, then Darwinism’s sphere of explanatory inference is too small to matter.