Colour genetics..

[SpottyTB]

Hi there - sorry if this is a bit of a long winded post!

Trying to get my head around colour genetics.... slightly unsuccessfully so asking for help!

So...I've got a mare, she's a chestnut tobiano (got a lot of white), whose previous foal came out skewbald - the sire was a well marked skewbald.. now this time round the mare's in foal to a bay (the amazing Avanti Amorous Archie).. am i likely to get a skewbald??? or will it be a mini me and be chestnut/white?

She can't be homozygous and only throw chestnut/whites if her first foal was skewbald surely - or would she if the sire was homozygous too?

I'd actually really love a solid bay, but somehow i think my chances are pretty slim!!!!

Thanks in advance, and sorry it's a bit of tedious post!
STB

 

[Meowy Catkin]

OK, skewbald means any colour other than black, with white patches. So chestnut and white is skewbald.

Do you mean a bay and white tobiano when you talk about her previous foal's colour?

 

[SpottyTB]

Right.. i've always assumed bay/white was a skewbald and chestnut/white was just that, chestnut/white - learn something everyday!
Yes, i do mean bay/white tobiano.. trying to post a photo of the foal rather unsuccessfully.

 

[Meowy Catkin]

The mare only has chestnut genes to pass onto her foal. I don't know if Archie has had any chestnut foals or not? If he does carry chestnut, then you could have a chestnut foal. If he passes on black + agouti (together they make bay, brown or wild bay depending on which form of agouti it is) then the foal would be bay/brown/wild bay even with one chestnut gene from the dam. If the foal gets black, but no agouti, then it will be a black foal even with the chestnut gene from the dam.

Now if the dam has two copies of tobiano, then 100% of her foals will be tobiano. If she only has one copy, then there is a 50% chance of her foal being tobiano.

 

[SpottyTB]

Ah ok that makes sense! Yes Archie has chestnut offspring and a similar looking mare (same colour and same sire to my mare) had a chestnut and white foal too... so i guess that's what i'm going to get! Not sure if mines got one or two copies of tobiano - i think there are tests done, so may have to look into that if we decide to breed again!!

Failed again at posting photos - sorry!
Thanks for the reply Faracat, it makes sense now!

 

[GemG]

You must post pics when the foal arrives!! or let us know what colour at least!

 

[ester]

so you know the mare is ee and either has one or two copies of tobiano
you do not know what her agoutis status is

Archie you know is Ee if he has had chestnut foals and Aa or AA at a agouti.

if you have a play on the calculator with that info
http://www.animalgenetics.us/Equine/CCalculator3.asp

 

[SpottyTB]

Thanks for the replies!
Might get her tested as would be interested to know the make up there anyway.

Will definitely post foal pictures! I'm suspecting we will get a mini version of my mare!