What are the relative roles of coding DNA versus regulatory DNA thought to be in evolution?
Yes, a simple google search reveals millions of academic citations talking about &quot;regulatory evolution&quot;.
But it's a little over-simplistic to divide coding vs. regulatory DNA. Indeed, some coding DNA is in fact also regulatory at the level of determining gene expression in cis (a well-known example of this would be codon usage).
It is moreover incorrect to think that coding DNA products don't do gene regulation. This was recognized very early on in the ideas of &quot;structural gene&quot; vs. &quot;regulatory gene&quot;. These days we would call the latter transcription factors, we don't really use the structural/regulatory terminology anymore. Transcription factors do most of the actual active work of gene regulation in trans, in collaboration of course with regulatory DNA.
So in conclusion, yes it's important and there are tons of studies that you can google if you want to investigate these problems. I would suggest reading more about cis-regulatory and trans-regulatory elements. Of course, there isn't an exact mapping of coding&lt;--&gt;trans and noncoding&lt;--&gt;cis, it's just a helpful simplification.