Roan?

Discussion in 'Colour Questions' started by JessiTrist, Sep 18, 2008.

  1. JessiTrist

    JessiTrist Well-known Member

    Is roaning always passed on? Does anyone have any information on the genetics of roan horses that they could share with me?
     
  2. samm

    samm Gold Member

    Roan has to be passed directly from parent to offspring even though it can be masked by colours such as grey and cream.
    Roan is thought to be lethal in homozygous form.
     
  3. JessiTrist

    JessiTrist Well-known Member

    Thanks Mel, this is a roan, isnt it? It ois Chickie's sire.
    [​IMG]

    Does that mean if Chickie ever had foals, they would also be roan?
     
  4. kiraSpark

    kiraSpark Gold Member

    I would think that was more Sabino colouring?

    Sabino horses have a pattern of white patches accompanied by splashes, spots and ticking. Most sabinos have flecks or roaning, especially those with extensive white. White marking on the face is a common characteristic of sabino. This might only be a few white hairs, but sabino horses are well known for often having extensive white markings, from a large blaze to “bonnet”, "apron" or “bald” faces. There is commonly some white on the chin and/or lower lip. Leg white is also common among sabino horses and may affect all four legs, ranging from coronets to high stockings. There can also be white patches on otherwise colored knees. Most sabino horses have lacy, speckled patches on their bodies with many tiny flecks of color or white near the edges. There are often roaned or speckled spots within larger patches.

    They are also often confused with roan. The term sabino means "pale red" or sometimes "roan" in Spanish. However sabino is genetically distinct from both overo and roan, is caused by different genes and not associated with lethal white overo syndrome. Also sabino can occur with any coat color and is not confined to chestnut. Shires and Clydesdales are exclusively sabino, though the markings may be limited to white face and leg markings.

    I would say Chickies sire isnt a roan because Roan horses have white hairs fairly evenly distributed throughout the coat of the main body, with non roaned heads and points (mane, tail, and lower legs).
     
    Last edited: Sep 18, 2008
  5. Playin With Fire

    Playin With Fire Well-known Member

    Good info Kiraspark!! Interesting read.
     
  6. JessiTrist

    JessiTrist Well-known Member

    Thanks Kiraspark.

    So can roan 'happen' without a roan parent? Or is Chickie just a weird colour I should stop pondering about?
     
  7. Kintara

    Kintara Well-known Member

    True Roan needs a roan parent, not so sure about the sabino roaning. As sabino is a combination of genes or expressions it might look to just appear out of nowhere sometimes just because of the combination of the parents genes. Mostly though I would think it would be visible somehow on one of the parents. Appy obviously can cause a type of roaning too.
    Cheers

    Danni
     
  8. kiraSpark

    kiraSpark Gold Member

    No. Roan must have a roan parent. And even then, unless the horse is homozygous for roan, its only a 50/50 chance of passing it on.

    But as Samm mentioned, roan CAN be masked by a grey gene.


    Here is some info about the research done into the possibility of Roan being lethal in homozygous form, interesting i thought.....

    The allele that causes classic roan is dominant, so that heterozygotes show roaning. Until recently it was thought that roan was recessive lethal, and that homozygous roan embryos died in utero in very early pregnancy. If this was so then no adult horses would be homozygous, and therefore true-breeding for roan. A study by Hintz and VanVleck in 1979 popularized the idea of a Lethal Roan Syndrome, although many breeders didn’t - and still dont - agree.

    According to research done by Dr. Ann T. Bowling at the Veterinary Genetics Laboratory of the University of California, roan is not lethal when homozygous. Her research supports the findings of earlier reports that confirmed the existence of homozygous roan stallions in Ardennais (a French breed) and Hokkaido (a Japanese breed).

    From a fairly large study of roan horses in the American Quarter Horse Association (AQHA) stud book Dr. Bowling identified several stallions apparently homozygous for roan. Breeding data was supported by a molecular genetic analysis of genes very closely linked to roan.

    The molecular nature of the roan gene isn’t yet known, but its position in the genome is, based on its genetic linkage to nearby genes. The stallions were found to be homozygous for the alleles of these genes that are linked to the roan allele, indicating the likelihood that they are also homozygous for the roan allele. The conclusion of their research was that there was no evidence that roan is lethal when homozygous.

    To my knowledge this research wasn't published, although I would be grateful to anyone who could update me if this is wrong. I have also heard of critisism from one person who claims there are serious flaws in the research. According to her not all the horses in the study were true classic roans, which included frosty roans, rabicanos and sabinos. Also she claims that one of the AQHA stallions that was supposed to show 100% roan production did not. At this time I am not able to confirm or refute this information.
     
  9. JessiTrist

    JessiTrist Well-known Member

    Thanks Danni, her dam is a leopad appy, so could be any colour under there, and this is one of the most recent photos of Chickie, who is definately a roan of some sort.

    [​IMG]
    [​IMG]

    So if her sire isnt a roan, but a sabino, then her dam a leopard appy must be a roan of some sort?
     
  10. kiraSpark

    kiraSpark Gold Member

    I think you might find Chickie is simply an appaloosa with some sabino characteristics, which from the previous description, you can see Sabino patterning can include some ticking/flecks or roaning in large areas. :)

    True roaning is evenly dispersed throughout the coat, bar the legs and head. I dont think shes a roan.
     
    Last edited: Sep 18, 2008
  11. Kintara

    Kintara Well-known Member

    Could be appy roaning, could be sabino roaning, or a combination of both!! :)* Appy's are fun because they can change so much!
    Cheers

    Danni
     
  12. JessiTrist

    JessiTrist Well-known Member

    Thanks guys, I will stop trying to figure her colour out now!

    On her rego papers it says she is a 'red roan'. Is that correct, or should I just change it and put 'confusing appy colours'? LOL
     
  13. Cav

    Cav Gold Member

    Long but interesting.....

    Below is a pic of my old pony Balmoral Morven..a TRUE chestnut roan.
    Notice the solid head and legs (markings allowed of course). He is 23years old and has never changed from this colour. His sire was a Grey and his Dam was a Bay.


    [​IMG]

    Here is some reading material on "Roans" ...

    Descriptions of roan coats warrants its own terminology:

    Red Roan or Strawberry Roan describes true or classic roan on a chestnut base coat. The mane and tail remain red or have only a few white hairs, while the body ranges from nearly chestnut to pinkish.
    Bay Roan is true roan on a bay coat. The particular shade depends on the underlying shade of bay, but the mane, tail, and lower legs are black and the reddish body is intermingled with white hairs. The head is usually red. Formerly, bay roans were lumped together with red roans.
    Blue Roan is true roan on a black coat. The mane, tail, head and legs remain black while the body takes on a grayish or bluish appearance. Blue roans are sometimes mistaken for grays or grullos. However, Grays fade with age, while roans do not, and grullos are blue duns and possess dun markings but not intermingled white hairs.

    Any coat color may be affected by roaning. Few combinations have the same unique terminology applied to the common roan colors, although palomino roans are sometimes called honey roans.

    Roan is a coat color found in many animals, notably horses, cattle and dogs. It is defined generally as an even mixture of white and pigmented hairs that does not "gray out" or fade as the animal ages.[1] There are a variety of genetic conditions which produce the colors described as "roan" in various species.

    Classic or true roan
    Horses with the classic or true roan pattern may be any base color which is intermingled with unpigmented white hairs on the body. Except for white markings under the control of other genes, the head, mane, tail, and lower legs are dark or unaffected.[3][2] The overall effect is that of a silver or lightened appearance to the affected part of the coat, which is reflected in the terminology used to describe roans. Black horses that are true roans are often called "blue roan" and likewise, true roan chestnuts are sometimes called "strawberry roan."

    Classic or true roan is always present at birth, though it may be hard to see until after the foal coat sheds out. The summer coat may be lighter in the summer, but unlike grays, true roans do not progressively lighten.[2] While the head of a true roan, barring any white markings, remains solid throughout its life, the first indication of "graying out" is often observed around the eyes and muzzle of foals.

    A peculiar characteristic of the roan coat is that after the skin is broken or scraped, the coat grows back without any white hairs. These are called corn marks. Another useful characteristic is that the unaffected color on the legs forms a sharp, inverted "V" above the knee. This is not true of other roan-like coat patterns.[4]

    True roan is caused by a simple dominant gene[2] that has been assigned to equine chromosome 21 (ECA21) in the KIT sequence.[3] Other important coat color genes in the equine KIT sequence include tobiano spotting,[5][6] extension (black), sabino-1 spotting,[7] and at least four other dominant white-spotting patterns.[8] These characteristics are part of equine linkage group II (LGII).[9]

    A study published in 1979 examined percentages of roan foals produced by roan parents found fewer than expected for a simple dominant trait. At the time, lethality of genetic conditions was based primarily on statistics, as modern methods of DNA testing and mapping had not yet been developed. [10] Neither finding stillborn or short-lived foals from these roan parents, the researchers concluded that in the homozygous condition the roan gene was lethal to the embryo or fetus. Contemporary studies were beginning to identify conditions such as "dominant white" and "lethal white," and so roan was believed to follow a similar pattern. Genetic science in the 1970s could not provide a clear answer. "Lethal roan" has since been discredited by the identification of homozygous roans[11] and the work of the late Dr. Ann T. Bowling, who found no evidence to suggest that homozygous roan was lethal.[12]
     
  14. kiraSpark

    kiraSpark Gold Member

    Oh yeah this is the same study I referred to, as well.
    Great info Cav, and an interesting read. :)
    Your pony is lovely, now THATS a roan LOL **)
     
  15. Playin With Fire

    Playin With Fire Well-known Member

    That pony has a nice butt Cav!!
    So in conclusion does a roan have to have a roan parent or not?? I is confused??
     
  16. Kintara

    Kintara Well-known Member

    LOL! Red Roan isn't really correct, but it probably doesn't matter too much. Is this Clydesdale Sport Horse rego? It would be more accurate to say Bay Appaloosa or something. Appy enthusiasts, what would her markings be called? Snowflake? I'm not that good at the appy patterns!
    Cheers

    Danni
     
  17. kiraSpark

    kiraSpark Gold Member

    Yep a roan has to have a roan parent :)
     
  18. Kintara

    Kintara Well-known Member

    Yes! True Roan that is.. :)*
     
  19. Pepsea

    Pepsea Gold Member

    for colouring id put appy lol

    for cream, silver etc they can pic ity up in a test.. could jess get chicki tested for her colouring?
     
  20. Playin With Fire

    Playin With Fire Well-known Member

    Ok
    Phew brain overload
    Ive learnt something new today!!
     

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