[QUOTE=Twisting;8954386]
Technically there are only 2 base colors. Black and red. Bay and brown are both carried on the agouti gene, and modify a black based coat. Wild bay is another version of the agouti gene. It causes minimal black points. Those “bay” horses whose black points only go up to their fetlocks, and maybe a splash of black on the knee.
Fun Fact, the ancestors of the modern horse were all bay, non-agouti is the mutation, and it was mostly likely the first color mutation in horses. Red being the second one we can track. It is hypothesized that ancient equines were also all dun, but the non-dun gene mutation hadn’t been isolated at the time of the study so there is no real evidence.[/QUOTE]
This is incorrect. Extension and agouti work together to produce the three base colors. Bay is NOT a modifier. There are two pigments, black and red. There are three base colors, black, red, and bay. This may help to explain: http://equinetapestry.com/2014/09/bay-is-not-a-modifier/
