HGG Community Forums

Dense Pheomelanin causes red pigment to build up in the hairs so that the horse appears darker than normal, an effect rather like Sooty has, though not necessarily building from the top down.

Ammit once explained it this way. Horses have a potential for having 4 coat darkening genes--2 Ssty and 2 DP. (DP will only affect the appearance of horses that have at least one recessive e, but can be carried by any horse.) So, if you have a horse that looks darker than you would expect it to be based on how many Ssty alleles its gene test shows, it is likely to have DP. If its a lined horse, you can check to see if there is DP showing in its pedigree as well, to help with the diagnosis.

Chestnut horses that carry DP and at least one dominant Ssty will color test as Liver Chestnuts. Here are some sample Liver Chestnuts as examples.

Homozygous SSty and DP

http://www.huntandjump.com/horse.php?horseid=3401814

Heterozygous S+, likely homozygous DP

http://www.huntandjump.com/horse.php?horseid=3419225

Heterozygous Ssty, probably homozygous DP, definitely heterozygous DP

http://www.huntandjump.com/horse.php?horseid=3111913

Here is the dam of the last one. She is homozygous recessive sooty, but looks much darker than you would expect for a non-sooty chestnut horse.

http://www.huntandjump.com/horse.php?horseid=3062101

Here is a non-sooty chestnut for comparison.

http://www.huntandjump.com/horse.php?horseid=2443315

The presence of dominant Pangare, either homozygous or heterozygous, will cause lightening of the color in the usual places, even when DP is present, just as it does with Ssty.

Thank you everyone. That helps a ton.

I have a mare on the other server that I was curious about. She looked darker than any chestnut I had previously created so I had her color tested. The following are her results:
ee AA CC dd gg Ff SS PP WF: None

And an image of her:


I know she is homozygous pangare but she recessive sooty, correct? So I am curious, is she DP or just a really red chestnut?

How can it be determined that she is a single copy of DP? Would she have been as dark as a heterozygous sooty if she had two copies?

Oh, okay. Thank you. :)