1997 A.Q.H.A. Stallion "IMA STAR BRINDLE BAR"
Reference Sire. Not advertising for Stud here.
Basically there is so little testing done on Brindle colored horses because there is not many of them out there to test on. It appears there is two ways in which a Brindle phenotype (outward appearance) can occur. In some horses, the pattern has not been inheritable
They have completed a few tests on Brindle colored horses with more striking pattern like the ones pictured below and what they found was that each horse had two genotypes which is extremely rare. It seems that the more striking pattern is the result of two embryos blending to form one individual.
There also seems to be another type of Brindle patterned horses and that is one like "Punky" and his Dam "Star" have produced so far. This pattern is not as "Striking" as the pic's below and it is harder to see from different angels and or lighting on some horses and others it's easier to see. (more pic's of different Brindles) This pattern has proven to be inheritable unlike the more striking pattern. Star has produced four foals to date, three of which carry her seasonal pattern. This indicates there may be a gene involved, which is inherited dominantly, since approximately 75% of her foals have inherited the pattern from her.
Many people confuse the
Brindle pattern with Dun Factor markings (stripe down the back, barring on the
legs, and occasional regular-spaced striping down the ribs or even heavy shading
coming down from their dorsal stripe). At one time, it was
thought Brindle was a just a variation of Dun Factor. Indeed, there have been
many examples of horses that were probably carrying both Dun Factor and Brindle.
However, many do not have any Dun Factor markings whatsoever, indicating the two
patterns are distinct genetically.
Brindle horses also have texturing in their coat, similar to that seen in some Appaloosa horses. The pattern seems to be inheritable, especially in terms of coat texturing, but the expression of the darker or more intense pigment to make the pattern visible is highly variable, and even varies with individual horses seasonally / yearly. Sometimes the pattern seems to be composed of dark hair (black or brown), sometimes of white hair (roan or gray).
There is a great site about Brindle horses filled with information to check it out go to THE BRINDLE HORSE SITE
these are two horses below that display the brindle pattern but are PROVEN to be Chimeric
Stallion on Left is Dunbars Gold, owned by Carole Dunbar mare on right is "Sharp One" owned by Denise Charpilloz of WA.