HGG Community Forums

It makes horses darker.

So, there are two different genes that can darken a horse's coat, sooty and DP or Dense Pheomelanin.

DP makes red hairs darker red and is involved in making liver chestnuts and chocolate palominos but will also show on bays, brown, other red colors and wild bay.

Sooty has 3 possible alleles--S, Ssty and S+. S is the non-dark version, Ssty is dark and S+ is even darker. Sooty seems to act by increasing the number of black hairs in the coat, thus darkening the overall appearance of the coat. S+ May also add an interesting mottled dapple appearance to the coat.

As mentioned already, S+ and the other darkening alleles don't really show up on black non-dilute coats. They may be more noticeable when your black horse carries a diluting gene like silver. This guy is an example.


http://hj2.huntandjump.com/horse.php?horseid=382793

The 3 sooty alleles are co-dominant. This means that a SS horse is the lightest, then SSsty, then Ssty Ssty. S+S+ is the darkest of the possible combinations, buy Ssty S+ will be darker than SS+.

In a gene with normal dominant-recessive alleles, SS+ would look the same as S+S+, a little like a bay horse that is Aa looks the same as AA.

Ok, it's 3am and that appears to be as much coherence as I have to offer you! If that doesn't make sense, please ask further questions! Also remember the Horse Search is your friend. If you go to the search there are 3 tabs--Key Filters, Base Color and Patterns. The sooty alleles are under base color, so try playing around there with different combinations and see what the same base color can look like with different degrees of darkness!