Colour Q! How does my grey mare have brown patches?!

C

chestnut19

Member
Joined
6 December 2009
Messages
17
Visit site
As title really! I have a mare who has faded out from a very dark grey (I think born Dark Bay) to almost white but has large patches of very dark brown colouring. I have also seen it in the Holstein stallion Acorado II. How does this happen as I thought grey was dominant? Thank you
 
Is she a grey or a Bay Roan? I have two Shagya Arab mares from Hungarian national stud (foundation stud for the breed). They are almost white with some brown points on hocks.

In the Hungarian stud book they are Bay Roan in French Stud Book they are grey.
 
I have had a quick look at blood marks (thanks to google!) and I think you are right Cruiseline, that is what they are. Thanks for your help.
 
It is thought that the blood marks are a result of the hair folicles being deeper in the skin so that they grey effect gets to them more slowly or in some cases not at all. You see it a lot with grey leopard appaloosas, the spots go grey quite slowly, much slower than a base colour would . Fleabitten greys are also a good example but in blood marks the deeper hairs are all together in one spot.
 
Gosh I never thought of flea bitten greys being blood marked, but it makes sense. Whe have a flea bitten that seems to get more spots the older he gets, my daughter said by the time he is 20 he will be bay again.
 
Found the paper! The research that found grey found that those that tested homozygous went grey quicker than heterozygous, but they found that they were also much more prone to melanomas some of which can become malignant.

They are theorising that in some heterozygous greys like yours, there is a separate gene at work that blocks the effect of grey locally, how that works is not yet known but somehow it allows the hairs to remain the base colour or even like yours to repigment after going grey. They are saying they think this is a recessive, but they have a lot more research to do around this. But if this is right it seems not to be able to override 2 copies of the grey gene.

I wonder if it's related in some way to white ticking as it is almost like a negative effect of rabicano/sabino/rount?

Grey is a separate gene in a different location to the coat colours, so it has an epistatic effect, it affects them from a distance. What they think it does is prematurly age the pigment production cells.

In in the research they found that the Grey Mutation was in the same location in all breeds suggesting a common ancestor to all greys, probably an early Arab.
 
You must log in or register to reply here.
Top