This one was born what I though was a dark red dun but base tests showed him to be a bay/brown AA Ee I am awaiting his test for the t gene (he'll be the first to be tested in the UK) at the moment that might explain the colour but here is one of him grown up as well.
I am assuming that one of Pancake's parents is a dun? if not you could be looking at black and tan the newly found t gene that distinguishes it from the A series Bay. Or she has the theorised pangere, the mealy muzzle seen clearly in Exmoor ponies, but I am not convinced that one is a gene in it's own right and might be explained by t and dun.
I have loads of duns - true duns that is, not buckskins, tho I have a buckskin too! You can see them all on our stud website. This year so far, we've only bred one dun - a chestnut dun colt. Last year we bred two chestnut dun fillies, the year before a blue dun filly. In addition we own a bay dun stallion, a bay dun mare, a blue dun gelding, a blue dun mare, and two chestnut dun mares - as well as a number of 'normal' colour horses, i.e. chestnuts, bays & blacks.
Don't think they have to have dorsal stripe, well my dun doesn't. Wouldn't duns have to have some dark brown colour on their legs? All the duns I've seen do, including my own.
I'm also very confused by all of this and have a chocolate dun!
I found this when I was looking just now...
"Dun can dilute both red and black coat pigment. The dun gene seems to affect the distribution of pigment granules in the hair, moving pigment away from the 'air-side' of the hair and towards the 'skin-side' of the hair, leaving the part of the hair which is clearly visible with much fewer pigment granules - hence the dilution of visible colour. It is the one responsible for the primitive markings of dorsal stripe, shoulder stripe, and zebra / tiger stripes. "Cobweb" markings can also appear on the forehead. Additional dun markings are face mask, neck and / or shoulder shadowing, 'barbs' from the dorsal stripe, and ear tipping, outlining and barring. Duns also have dun dilution (the same colour as the body coat or a few shades lighter) at the sides of the mane and the frost-cap at the top of the tail. Dun doesn't touch the lower legs, so it's what I call a 'pattern dilutant'. To the best of current knowledge there appears to be no visual difference if a horse has inherited one or two dun dilution genes. If he has inherited the dun gene from both parents, of course, he will pass it on to ALL his descendants. For (probably) the best article on distinguishing between true duns and buckskins (cream dilutes) with counter-shading caused by the sooty gene, see Dun Central Station's excellent article "What's Dun is Dun!"..
Breed Societies, please try to ensure that duns are registered under their right colour! It's unhelpful when researching pedigrees if every type of dun is simply registered as 'dun', as opposed to golden dun, mouse dun, blue dun, (any of which could be 'silvered'), and red dun, etc.! And please don't register buckskins as duns! Pictures of 'true duns' and colours frequently confused with (and mis-registered as) dun can be seen on our 'Dun and Un-Dun' page. " http://www.seaspiritoftheforest.co.uk/equine/HorseColoursAndMarkings.html#chocodun
Have just posted a guide to colours on the Buckskin thread above but don't get hung up on dorsal stripes as they are inherited separately, some bays have them so therefore so do some buckskins. Then there are the combinations which are dun and cream, so it is sometimes very difficult to tell by just looking at a horse and not its pedigree or test results!!
The foal above is probably just a bay with a dorsal stripe if it did not have a dun parent. Foal coats are often very misleading and you will know more when the moult is over.
The horse I pictured above is a dun but over a bay or brown base. I may know more as to why he is not yellow towards the end of this week when his t gene results come back from the USA. His father an American bred Appaloosa was as it turned out a homozygous dun from a line of duns and his grandmother was the colour he is.