Lemme just say I know next to nothing about colors, but I was looking at my guy and he's weird. Lol. But I've always noticed this but never thought much of it. Why does my palomino have a dorsal stripe? Also, I think he's sooty because his mane has some black strands. Also when he sheds out he has super dark almost black patches like on his butt and chest. But does sooty make him have spots too? He has like 3-5 big solid dark brown spots.
In the first one you can see his dorsal some and the biggest black spot.
In the second one you can see more black spots like on the inside of his knee and back.
And the last one you can sort of see how black those splotches on his butt get. It's darker up close but I don't have many good pictures.
Sorry for the length, I'm just super curious with little knowledge in this area. (:
A 'real' dorsal stripe is associated with the dun gene and is very crisp and clearly defined, as if someone took a thick marker and drew a line down the horse's back. Often it will appear as though it continues into the tail. Here's a good example:
Countershading is not associated with any particular gene and can appear on any color horse. It's not usually as clearly defined, however it rare cases it can appear just as defined as a true dorsal (in which case you'd have to determine if the horse has carries dun through some other means, such as genetic testing). There's one HF member who has a very good picture of her Arab with a very distinct dorsal- in this case, it's genetically impossible for the horse to be dun (Arabians don't carry the dun gene) so it can be determined that it's just countershading without genetic testing. However, in some cases it can be very hard to tell for sure just by looking.
The opposite also happens- the dorsal stripe on some colors is not very pronounced (happens a lot on double dilutes, and sometimes on single dilutes like dun palominos). Breeders & owners who don't know a lot about color won't recognize the subtle signs of the dun gene because it's not very pronounced, and then when they breed that horse they get unexpected duns!
Ahh, okay that all makes since. Well thanks y'all, maybe he's not so weird lol (:
No, not weird - pretty normal. Just FYI, dorsal striping is the vestige of the "dark on top, light on bottom" pattern that many, many animals of all sorts and species display. It is a basic camouflage color scheme where the dark blends in with the ground from above and the light blends in with the sky from below, as well as a "heat absorption from the top and cold rejection from the bottom" color scheme...