what colour???

Discussion in 'Colour Questions' started by badpony, Dec 19, 2011.

  1. badpony

    badpony New Member

    i have a beautiful liver chestnut shetland pony filly and im wanting to put her in foal in few years time to my friends black and white pinto stallion. what are the chances of getting a pinto??
     
  2. norwest star

    norwest star New Member

    have a look on the colour calculator
     
  3. Genetically it depends on whether the stallion is homozygous for the pinto or not.

    If he is homozygous for (as an example) tobiano then the resulting foal WILL be, genetically, tobiano. If he is heterozygous, then it's 50/50. HOWEVER, pinto can and does hide, so genotype (what the horse is, genetically) does not always equal phenotype (what the horse LOOKS like).

    Give me a moment to explain zygosity. A horse is homozygous for a particular gene if it carries two copies. For example, with tobiano, T/T is the homozygous state. A horse is heterozygous if it only carries one copy if that particular gene - with tobiano that is T/n. If the horse is a frame overo it cannot be homozygous as the gene is lethal in its homozygous form. If it is sabino or splashed white it can be either.

    For black/chestnut the gene we consider is E for black or e for chestnut. The capital letter is always the dominant gene and the little letter always the recessive gene.

    SO, your mare, being chestnut, will carry e/e for red/black factor. Agouti, the gene that makes an E/e or E/E horse bay, is unknown, as it does not express on a red based horse. For purposes of calculation we will make the mare A/a which means heterozygous.

    The black and white stallion MAY be truly black or he may be seal brown or real dark bay. For our purposes here we will assume he is true black. So genetically he can be E/e or E/E and then whatever his zygosity for the pinto pattern.

    From a chestnut and a black the ONLY base colours you can get are black, bay (or brown which is a variant of bay), or chestnut. From there you add the pinto pattern, for which we will assume he is heterozygous.

    You have 50/50 for red/black which means you'll end up with 50% chestnut, and 50% black-based. Assuming the mare is heterozygous for agouti you will then have 25% bay/brown (I don't feel like separating the two, it's too complicated) and 25% black. To get the pinto pattern we then get:

    25% solid chestnut
    25% pinto chestnut
    12.5% solid bay/brown
    12.5% pinto bay/brown
    12.5% solid black
    12.5% pinto black

    From a practical standpoint either the stallion owner can have him colour tested, or you can look at previous foals if he has sired any. If they are all pinto coloured there's a pretty good chance he might be homozygous. If there are solid coloured foals then he's most likely to be heterozygous. Same goes with black/red base - colour testing is most reliable but his get can also be telling. If he has EVER sired a chestnut foal then he must be heterozygous. If he has never, there is a chance he may be homozygous.

    Does that help or have I confused you with all my genetics-babble?

    edit; I did all that in my head so if anyone goes through the colour calculator and puts in heterozygous for everything it asks for zygosity, and gets different percentages, do correct me?
     
    Last edited by a moderator: Dec 19, 2011
  4. badpony

    badpony New Member

    hey yer it kinda makes sense lol im new to the whole genetics stuff...lol but i some what understand thank you :) i have to ask my friend bout her stallion
     
  5. Genetics can be very complicated and confusing! You're lucky, you're just dabbling in black and chestnut, and adding pinto or not pinto into the mix doesn't make it much harder. It gets tricky when you have two horses that are heterozygous for whatever trait you specifically want. Say for example you want to breed a black foal, but you only have E/e parents and one is also A/a (making that one bay, and potentially the foal as well). That's a relatively simple one.

    When you get into the silver buckskin dun splashed white, frame and tobiano (YES it happens!) bred to a grey horse that was born smokey grullo (as in black dun with a creme gene) it gets really complicated. And I am now tempted to go to the colour calculator and find out what likelihood of what colours might pop up with such a pairing...
     

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