The brain is a physical structure. So is it inconceivable that some genes may code for phenotypes in both the brain and external appearance, or have some indire

The brain is a physical structure. So is it inconceivable that some genes may code for phenotypes in both the brain and external appearance, or have some indirect purely biological relationship? I’m not suggesting that this would account for a significant portion of the correlation between external appearance and behavior (if any at all), but maybe it’s enough to be picked up subconsciously. Domestication syndrome seems to suggest a link. [1] 1 - https://en.m.wikipedia.org/wiki/Domestication_syndrome https://en.m.wikipedia.org/wiki/Domestication_syndrome