Grey Homozygous Stallions?

Discussion in 'Colour Questions' started by Trojane, Jul 24, 2008.

  1. mamma mia

    mamma mia New Member

    I believe they can now DNA for grey in Britain but it is not yet commercially available. All of us who DON'T want grey but who have a couple of heterozygous grey mares in the broodie band because they are just too good in all respects apart from the colour, will be waiting eagerly for the test to become commercially available so we can test foals and say by a few months of age whether or not the horse will grey out.

    I was reading somewhere -maybe here - that linking the grey DNA test to the overall genome of the horse reveals that all grey horses descended from one common ancestor tens of thousands of years ago, or even further back. I believe they can trace to a common ancestor via the mitochondrial DNA. One horse had a mutation in the ordinary colour genes that caused the complete loss of colour in the hair at an early age, and that single horse bred that colour mutation on until it is evident in nearly all breeds of modern horse. Interestingly, this gene must have gone through further mutations (my assumption) as we now have some lines of greys that go completely white by the time they are four or five, some that stay steel grey until they are over ten, some that go flea bitten grey, etc.

    Perhaps that single first grey mutation also had a mutation in the T-cells that attack cancer cells (by coincidence or perhaps the location on the DNA is adjacent) so that all grey horses develop cancer cells/tumours/growths easily whereas the other colours have the very active and normal T-cell production to detect any cancer cells early and deal with them. I am sure there will be further exciting research into this which may well carry over into the understanding and treatment of human cancers.

    I've been meaning to chat to Tintara about this and pick her brain on the topic (my knowledge comes from picking brains of people like Tintara!)

    Leanne O.
     
  2. samm

    samm Gold Member

    Why pay the money??
    If the mare has a non-grey parent it wont be homozygous for grey.
     
  3. Trojane

    Trojane Well-known Member

    Mamma Mia said:
    Hi MM, I posted on this recently:
    http://www.stockyard.net/vbulletin/...orses-all-related-breaking-genetics-news.html

    In the original paper from Nature Genetics, greying is thought to be due to overexpression of one or two genes (NR4A3 and/or STX17), which promote melanocyte proliferation. NR4A3 is linked with cell cycle regulation (and carcinogenesis). They believe STX17 duplication leads to overgrowth of skin melanocytes and thus melanomas. However the excess growth in the hair-follicle melanocytes depletes the stem cells...leading to premature greying. This theory is supported by the fact young grey horses darken before onset of greying.

    I hope that makes some sense!!
     
  4. Tintara

    Tintara Well-known Member

    Have PM'd you Kylie.
     
  5. Remaani

    Remaani Guest


    Cool, i knew you meant him. Lovely boy. :)
     
  6. citygirl

    citygirl Gold Member

    Thanks Trojane :)* ...lol this boy is just a grot of a horse..he loves being dirty !
    One reason I'm not keen on greys is if born chestnut..they look a yukky colour while they grey out...{ for a few years that is..#( } its like an offish pink colour ! lol other than that..I'd just love a chestnut filly from him **)

    His Sire & Dam are greys, his Dams parents are both grey, and his Sires Dam is grey....lol I dont stand a chance getting a chestnut filly by him do I ???

    cheers
    Lee
     
  7. mylittlepony

    mylittlepony Well-known Member

    sorry to say there are a few brown verglas offspring running around#( but the amount of greys hes produced is amazing!:D
     
  8. Trojane

    Trojane Well-known Member

    MyLittlePony said:
    Oh dear...strike him off then! It only takes one and he's out! :p

    And CityGirl, I think your chances are slim... but some of those greys in his family could be concealing G/g combinations. Chestnut may yet break through! Mind you, you'll be the first I know actually wishing for one (though I love my chestnut!!!) :D
     
  9. Dreamer

    Dreamer New Member

    Well his name is Billjim, 16.3 h.h., produced chestnuts and greys. Photo. can be found by searching WHOBAA.
     
  10. torridonequine

    torridonequine Active Member

    Andalusian Atomico

    Hi We stand Andalusian Atomico he is an outstanding stallion and although not many stock on the ground i would be surprised if he threw anycolour His dams side is totally homozogious and sire is grey .I own his half sister and she has never given us colour only grey to my black/brown stallion and to another black stallion.
    We also have a sec A stallion welsh who has only ever produced grey but he,s only 11.2hh Wendamar Selection .
    Go to www.torridonlodge.com - Home to view stallions
     
  11. Trojane

    Trojane Well-known Member

    Hi TorridonEquine and thank you for this. Some extremely handsome horses you have there!

    Have you had your "known homozygous" mare and others DNA tested?
    Also - in the ones never to have thrown a coloured offspring, were there many foals? Thanks for getting in touch. :D
     
  12. Kintara

    Kintara Well-known Member

  13. tsararab

    tsararab Active Member

    hi tintar that wouldnt be simmoon eskimo would it that mark used to have, he would be very old if it is but what stunner and multi multi supreme stallion he was i would love to know if he is still alive if any one knows. sorry for butting in like this
     
  14. Trojane

    Trojane Well-known Member

  15. dayna

    dayna Well-known Member

    OK I know it has taken me a while to dig out his piccies from my disc collection, but here they are.

    Montino V is a pure Andalusian, imported from Europe, he was tested as homozygous grey at Oxford University prior to travelling to Australia.

    These piccies are taken about 3 weeks after he arrived here, he has totally greyed out now to almost white.

    [​IMG]

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    [​IMG]
     
    Last edited: Aug 25, 2008
  16. Trojane

    Trojane Well-known Member

    OOOoooH!!!! You are so lucky!!! Thanks for showing us Dayna. What a magnificent boy! Is he good to handle too and working nicely for you?

    Can you tell us a bit about how and where you found him and was it much hassle getting him back?
     
  17. dayna

    dayna Well-known Member

    Thank you Trojane. He is very quiet to handle, however he is very hot headed under saddle.

    I brought him when I was living in Germany, I wanted a dressage horse and always wanted an Andalusian after visiting El Caballo as a child. I had an Andalusian gelding prior to heading over to Europe and loved thier temperment. So I went on a tour of the studs over there and fell in love as soon as I saw him.

    Getting him here was not too much hassle. The transport company organised everything. I was not impressed that he was stood on the tarmac in Singapore in the heat waiting for his connecting flight, but other than that it was relatively painless.
     
  18. Trojane

    Trojane Well-known Member

    Yes I loved the Andalusians at El Caballo too. What a dream - to cruise the studs of Europe! But I'd find the whole process completely overwhelming...hard enough choosing at home! Sounds like the transport companies have things well sorted (apart from the hot tarmac wait). As for fiery under saddle - well they look best that way (hehe - okay for us on the ground). Good luck with your dressage future!
     

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