Question about Tetrach Spots and Greying

[stolensilver]

Does anyone know how different greying patterns are inherited?

I have a heterozygous grey mare who greyed evenly and slowly as she grew up, kept a black mane till she was about 9 and started to get more and more flea-bitten from 7 onwards. She’s now 19, rising 20 (where has the time gone?) and is almost 50:50 flea-bitten brown. Interestingly she has no visible melanomas.

She’s had two grey foals who are greying out in very different ways. The colt is by a heterozygous grey stallion. He started off chestnut. He is greying out with big Tetrarch spots all over him.

The filly is by a seal brown tobiano stallion. She started off dark bay, maybe seal brown with no white markings and is greying out like her dam did, a gradual sprinkling of white hairs appearing throughout her coat.

I’m wondering if the Tetrach spots have come from the grey gene from the grey stallion? The more normal pattern of greying shown by the filly has to have come from her mum.

Or doesn’t greying work that way?

Also is there any link between flea-bitten greys and no melanomas? It makes sense to me that there should be as the melanomas are thought to be be linked to the redistributed pigment that is lost from the coat. If the coat regains pigment via the flea bitten pattern there is less displaced pigment throughout the body so therefore there’s less pigment to form into melanomas. Anyone know if this is right?

[EventerAJ]

I wish the fleabitten/no-melanoma connection was true… my mare is fleabitten gray but she is developing melanomas at age 14 (started tiny at age 11).

I don’t know her birth color; I got her when she was 6, a dark dapple gray. Her sire was bay, dam was gray. My mare has gradually lightened, and lost most of her dapples by 11. (Interestingly, my vet said that he tends to start seeing melanomas when the dapples disappear-- it was true for my mare.) She has just a touch of black still on her knees and hocks.

I have noticed different graying patterns-- I sort of wonder if it’s related to the color of the base coat? Many chestnut-based grays seem to go white very quickly at a young age. The TB sire Tapit tends to have a lot of fast-graying foals…many (most?) of his gray 2 y/os are nearly white, not dappled (ie Hansen, Stardom Bound). However, Unbridled’s Song tends to get bay/dk bay based foals, that remain a dark steel gray and dapple out gradually.

I’d be interested to know more about graying patterns, too.

[omare]

I thought there was some data showing a link between the color of the gray horse as a foal and before graying out and the pre-dispostiion or not for melanomas–just cant remember what it was–maybe grays that “co-exists” but eventually grays out another color?