I never understood this position from the logical point of view.
Say that you were put in front of two pictures that are entirely covered except for a small visible part each. The two visible parts of the pictures are different. Would you ever assume the parts that you can't see to be identical, or would you assume they differ from each other as much as the visible parts do?
Some very small genes have very large visible expression. Some large chunks of DNA have very little.
Let me change your italics:
Some very small genes have very large visible expression
So small parts of the DNA code for changes that we can visually appreciate. This doesn't mean that the rest of the DNA contains no variations, but just that we cannot see them. But it would be wrong to assume that the only parts that are actually different are those which encode for visible characteristics.
This seems like a clearly recognizable inherited trait, based on a large influence of certain small pieces of DNA. The abstract mentions eye color as well.
> When DNA recombines at conception, it only snips and stitches in a fairly limited number of places. It doesn't 'mix' finely like paint.
I had always assumed that clearly recognizable traits that children inherit from parents are simply based on the large influence of certain small pieces of DNA. Do you know a good text that discusses that?