What is the difference betweeen fading black, bay and brown?
Is there a true genetic difference (aguti gene) or just a visual one?
It is so hard to tell the difference visually that I'm wondering if you have either do a genetic test or look at the dam and sire? I'm more knowledgable of the dilute and double dilutes and am having trouble wrapping my head around the aguti gene concept. Pics would help!
Nonfading black and fading black are genetically the same (E_)
Bay is Agouti on black (E_ A_)
Brown is a form of agouti that acts on black (E_ At_)
Normal bay looks to b dominate over brown.
There is a visual difference between bay brown, and fading black (to some extent), but sometimes a horse can look both. The best way to know is to test, although knowing the sire/dam colors can help quite a bit. On the fading black, you just need to see the horse as it transitions into or out of their winter coat.
Fading black will fade all over, or in the usual 'burn' areas - the butt on either side of the tail is usually the first to go IME. Fading black is still genetically black, and can be homozygous. There was a theory that fading was hetero and non fading was homo but that was disproved. So a fading black horse would be aa for agouti. This horse is fading black.
Bay is your 'normal' bay, with a generally even tone. By that I mean the colour stays the same to the 'soft' parts of the body - muzzle, flank, elbow etc. Bay is caused by an A on the agouti locus - so a bay horse is Aa, AAt or AA. This is your average bay.
Brown is a bay horse with lighter 'soft' parts. They can be light bay to start with, or dark bay, even all the way to almost black. The soft parts of the horse are places that would not be the first to fade, and would not fade to the extreme seen in brown. Brown is on the agouti locus, and is At. A brown horse is Ata or AtAt.
This horse is brown. With a really dark coat, you can clearly see the soft points and how light they are. These points could not get this light without some other bleaching on the horse.
The confusion most people seem to have is that brown can look a heck of a lot like bay, just with the lighter soft points. Brown can still have black legs, even with really defined stockings. It can be on a really light horse. This horse is tested as Ata.
The reason I'm wondering is because my mare's dam is a Smoky Creme and all of their offspring (3) are Smoky Blacks. One would expect them to be buckskin if he were indeed a bay see chart CPEA Color Chart
You must be right he must be black (fading) because acording to the gene calculator my horse and her 3 full siblings would be 23.44% to be what they are if he were Bay but 93.75% to be what they are if he were Black.
He must be black!