predominant colours in certain breeds

[Stormin]

OK, so colours are based on genetics with dominant genes.

But why are some breeds more likely to produce certain colours, and why some breeds don't produce them at all ?

Arabs - lots of greys, never dun, palomino ...
Fresians - always black, do they exist in another colour ? (apart from the albino model)
QH - lots of red dun and grullo but not seen grullo in many other breeds
Irish cob - usually coloured ...
to name but a few

Anyone got any explanation out there ?

Thanks

 

[Stassy]

Could be the original fanciers/breeders of these horses liked their breed in a particular colour so only bred that colour(s) and those colours have stayed and been written into the breed description. Thats my theory anyway

 

[Stormin]

So that would mean that some breeds just don't have certain colour genes anywhere in their DNA makeup ??

 

[ambatt]

Arabs have no dilute colour genes.
Icelandics show every coat colour imaginable bar spotted (I hankered after a blue dun silver dapple mare for some time!)
Iberians have dun and also the cream gene, more common in Lusitanos than PRE where many colours were bred out as 'undesirable'. PRE (and PSL) also have the pearl gene which gives the effect of a double dilute...
Akhal Tekes have the cream dilute plus that beautiful metallic sheen.

Grullo is simply Black (E) with dun, but other factors can be present to give a variation in shading, but geneotypically they are black plus dun.

Friesians do carry chestnut, but is undesirable and bred out. As chestnut is recessive it 'hides' under the black.

There are NO true albinos in the equine population.

Lipizzaners once came in a whole host of other colours including spotted, but now come in the predominant grey and also bay and black (more common in the Hungarian and Central European lines than the Austrian-bred ones of Piber)

Some breeds do not carry certain colours, some come in only one colour such as the Sorraia (dun).

Silver dapple is the one often desired and quoted, it occurs in relatively few breeds.

 

[Stormin]

Thanks for that.
So basically alot has to do with breeding for (or not for) certain colours ?

And how do you explain that all fjords appear to have the same colour, and hafflingers too ?

 

[ambatt]

Simples! Selective breeding!

Also, in the past breeds such as the Haflinger were isolated from outside influences and bred 'true'. Also there is a school of thought (and some research) into the orignal 'true' wild colouration of equines and it is domestication that has introduced new coat colour, plus white markings are the product of domestication across all species not just horses.

There are some interesting papers here:

http://omia.angis.org.au/retrieve.shtml?pid=401

 

[Stormin]

OK, so all icelandic horses could have been one certain colour if they had canted to (being isolated and pure stock etc) ?

 

[ambatt]

OK, so all icelandic horses could have been one certain colour if they had canted to (being isolated and pure stock etc) ?

In theory, but instead they show a variety of coat colours and variations and colours seem to have been a prized attribute. Although roans are the most scarce...

Exmoors are and have been relatively isolated and breed true...