MARCH 5, 2008
NOTE: THE ARTICLE IS NOW AVAILABLE VIA PDF DOWNLOAD
~ Approx. file size - 2.2 megs
Comments, feedback, questions? ~ Send
Below is a very brief "sneak peek" at the article.
PRIMITIVE MARKING THEORY
By Nancy Castle ~ Dun Central Station
This paper hypothesizes that the dun gene does not add primitive
markings to the coat of a dun dilute colored horse. Rather,
the primitive markings are already present in the coat of all
horses. However, they are not distinguishable from the coat
of most horses because they are essentially "self-colored".
They are visually the same color and shade as the rest of the
horse's coat at the site of each marking. We can most often
see these primitive markings when the horse has a modifier that
changes the coat color, but has little to no effect on the primitive
markings. The dun dilution gene is the modifier that is most
often responsible for visible primitive markings. There are
also other modifiers that can cause primitive markings to be
visible at times.
I hypothesize that rather than putting
the primitive markings on the coat, the dun dilution gene essentially
does not dilute the primitive markings that already exist
on every horse.
Primitive Markings on Horses:
I first came to the basic conclusion that the dun dilution
gene does not dilute the primitive markings of a horse when
I noticed that many horses identified as bay based duns had
red or red-brown dorsals, while some had black dorsals.
Bay Dun Morab Gelding - Red Dorsal
Brown Dun QH Mare - Black Dorsal
I also noted that on the legs of obvious bay duns, any primitive
leg barring that is present within the point of the leg appeared
to be black, and any leg barring above the point area appeared
to be red or red-brown. If the horse had not been diluted by
a dun gene, the area of the leg above the point would have been
some shade of red or red-brown. Therefore, the color of the
primitive leg bars within the leg point vs. those above the
leg point indicated to me that these markings are the same as
the base color of the horse. Thus, it appeared that the dun
dilution gene was not diluting the primitive leg bars.
Leg Barring on Bay Dun Morab Gelding
Note that the upper leg bars are more red or red-brown,
while those lower within the leg point are black.
If the dun gene is not diluting the base color at the site
of each primitive marking, then a clear bay based horse should
indeed have a red or red-brown dorsal stripe, as that is the
base color of a clear coated bay along their top line. But why
would a bay dun sometimes have a black dorsal and sometimes
have only black leg barring, and not both red and black leg
While trying to determine why horses identified as the
same base color could have such different colored dorsal stripes,
I considered other possible modifiers that are known, on undiluted
bay horses, to change the color of the dorsal area of the horse.
||Left: Firestorm - bay dun
Morab gelding. Photo contributed by Kathy Morey.
Right: Cr Lobstick Ray - brown dun Quarter
Horse mare. Photo contributed by Aarin Cameron.
||Firestorm - bay dun Morab gelding.
Photo contributed by Kathy Morey.
To read the rest,
please click the file name below to download the full pdf document.
Approximate file size - 2.2 megs
Comments, feedback, questions?