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Brown shows up much better with sooty. It pretty much gives the horse a richer bay color.


14641976 RFB

The dominance order for the agouti gene goes like this.

1. Wild bay (+)
2. Classic bay (A)
3. Brown (t)
4. No agouti mutation (a)

Here's a link to Ammit's discussion of the agouti gene in the genetics guide:
https://www.huntandjump.com/geneticsguide/?page_id=48

Ammit builds this game to include a range of possibilities for almost everything, which is the case in real life.

S+ causes more intense darkening, especially along the horse's top line and also dappling, which is usually random.

You can't always judge a horse's genetics from it's pheonotype, nor predict it's phenotype from its genetics. D

Ahh, I finally read the genetics guide for both agouti and nd1. I don't think I knew that nd1 lightened color. Thanks for both of you for pointing those out.

So going back to the top, why is that horse bay, not brown?

That wouldn't have surprised me, but it doesn't seem to be the case. Here's a brown without sooty or DP

E/e a/t f/- p/- -/SB1

Autumn Ivy Rose

One more
E/E a/t W20/W20 PATN1/-

Kol

Homozygous brown (t/t) needs at least 1 sooty (or DP) to be brown. t/a is brown without sooty. The thing to remember about all the agouti genes is that they work by removing black from the body, not by adding it to the points.

Confusing genetics! Keeps the game interesting though!

@annismyrph Nope. Liver can only appear on red based horses. Agouti mutations can’t express unless the horse is at least het black, so liver is not an agouti mutation :)

That’s also why it’s termed liver chestnut. It can only express on chestnuts!

And palominos with the right gene combo, but palominos can only be red based.