If you cross a grey with a bay....

[Deleted]

Very interesting, especially as we breed the occasional bay/blue roan, as for chestnuts in the breed, there used to be a colour called Heckberry brown in Dales, i am told it was similar to a dark liver chestnut with dapples, there were also dark chestnut Fells, some still appear occasionally, mainly in a line bred at Caldbeck in Cumbria, this colour has cropped up occasionally going back many years.

[Debbie]

What do they do with the chestnut fell ponies? Can they still be registered?

Sadly in the 1950s, a lot of Paint (colored) foals that were born to dark quarter horses used to be sent to slaughter, as the foal was 'unacceptable'. Nowadays, the paints are exceedingly popular... go figure

I'd never heard of the Heckberry brown til I read about it on here ...so much to learn And I'm SO glad you're helping the roan lines along!!! I adore the colour variations, and the fact you're aiming for temperment and quality to boot

[lucydales]

Stolen this from the "other" board as I was pondering the same things also and this is the best explanation I've seen. It's worth reading through the thread if you visit them.

Peter D Hiatt

Equine Color Genetics Chart
GG---- is gray (homozygous) and can produce ONLY gray but passes on other color genes
Gg---- is gray with a 50% chance of producing gray when bred to a horse of color (any color)
gg---- is NOT gray. It may be bay, chestnut, or black. It can produce gray only when bred to a gray.
ggAAEE is bay, and can produce bay, but cannot produce black or chestnut
ggAaEE is bay, and can produce bay or black, but cannot produce chestnut
ggAAEe is bay, and can produce bay or chestnut, but cannot produce black
ggAaEe is bay, and can produce bay, black, or chestnut
ggaaEE is black, and can produce bay or black, but cannot produce chestnut
ggaaEe is black, and can produce black, bay, or chestnut
ggaaee is chestnut, and can produce chestnut, black, or bay
ggAAee is chestnut and can produce chestnut and bay but cannot produce black
ggAaee is chestnut and can produce chestnut black and bay
This chart assumes three gene pairs (Gg), (Aa), and (Ee). Each parent gives one gene of the embryonic gene pair. The resulting embryo's gene pairs are a result of statistical chance. This allows us to be able to calculate the probability of the resulting color and what the resultant foal can eventually produce itself.
As per the chart, the order of color dominance is as follows. Gray is most dominant with the large dominant G ALWAYS resulting in gray. Only one dominant G is needed for gray color. Oddly enough, the next most dominant set of genes is a PAIR of recessive chestnut genes (ee). A pair of these genes always results in chestnut unless a G gene is present. A horse will NOT be chestnut unless there are a PAIR of these genes present. The next order of dominance is the bay gene (A). Only one dominant (A) gene is necessary to produce bay if NEITHER dominant G (gray) gene or pair of recessive (ee) genes are present. Finally, the black recessive genes (aa) will result in black unless either gray (G), or recessive chestnut (ee), or bay (A) is present. As a result, the black gene can be present but stay hidden for many generations. We also see that only one bay or gray gene need be present to produce those colors, but both recessive chestnut or black genes must be present to produce those colors.
Here is an example how the genes split up to produce a foal. Let us assume that we have a stallion GgAaEe. This is a gray stallion. He is bred to a mare that is ggAaEe. This is a bay mare. Consider one color set of genes at a time. We are crossing the gray genes first Gg of the stallion to the gg of the mare. There are four possibilities. The first stallion gene is G which crossed with the two mare gray genes gives us Gg and Gg. Crossing the second stallion recessive gray gene with the two mares genes gives us gg and gg. From this we see that the foal has a 50-50 chance of being either gray or colored. Doing the same type of cross with next most dominant gene set (chestnut) gives us EE, Ee, eE, and ee. Only 1 chance in 4 of these is a chestnut. So far, there is a 50% chance of gray and a 25% chance of the REMAINING probabilities that the foal will be chestnut so 25% times the remaining 50% gives us 12.5% or 1 chance in 8 that the foal will be chestnut. Next most dominant is bay. The possibilities are AA, Aa, Aa, and aa. Since we need only one Dominant bay gene for bay, there is a 3 out of 4 or a 75% chance of the REMAINING probability of being bay. This is 50% (gray) minus 12.5% (chestnut) or 62.5% chance of more dominant colors so the remaining possibility is 37.5% (3 of 8) So 37.5% times 75% equals 9 of 32 or about 28% chance of producing bay. The remaining possibility is the chance of black or 100% minus 50% minus 12.5% minus 28% =9.5% chance of producing black…or about 1 in 10 chances. Yeah, a bit of math but fun.
A few examples will be the easiest way to understand how to use the chart. A black horse can have only one unknown color gene. A bay or chestnut has two unknown genes. A gray has five unknown genes. However, if the birth color is known, that simplifies matters. It is also probable that a gray's flea bite colors explain their bay/chestnut nature but these are often small and hard to distinguish between bay and chestnut. A gray born bay, for example, would be (G?A?E?). That reduces the unknown to 3. A gray born chestnut would be (G???ee). That still leaves 3 unknowns. Please be assured that the identification process and probability calculations are easier than first appears.
Your horse's registration papers include 4 generations of ancestral colors. The registry's computer disc is very helpful.
We will now examine examples of how to determine your horse's exact color code.
Easiest first! If you have a black with a chestnut parent or if that black has ever thrown a chestnut foal, the color code is ggaaEe. Please note that the term "homozygous gray" means that the horse can only throw gray (GG). However, the term "homozygous black" means that the horse can only throw black IF BRED TO ANOTHER BLACK. Two blacks can produce a chestnut (and a 25% chance at that!) if both their codes are ggaaEe. A homozygous black is ggaaEE. You can see that he has no recessive chestnut gene to offer offspring so no chestnut offspring is possible.
If a bay has a chestnut parent or if the bay ever produces chestnut offspring, it is ggA?Ee. Similarly, if it has a black parent or ever produces black, it is ggAaE?.
Chestnut gene codes are found similarly. A chestnut starts out as gg??ee.If it has a black parent or ever produces black, it is gg?aee. If a chestnut ever produces a bay when bred to a black, it is ggA?ee.
Now some folks always breed chestnuts to black to produce blacks. However, you can see that if the chestnut in question does not carry a black gene, the offspring will NEVER be black. The best you can get is an offspring that carries one black gene and then the grandget may produce black.
There is a very rare occurrence of a special black "gene" attached to the chestnut genes that produce black when bred to chestnuts. There is only one Arabian I have heard of that has this gene set up, but naturally, it is not an asil horse.
Grays are harder, but if a gray ever produces color, it is Gg. If it has a black parent or ever produces black, it is aa or Aa. If it has a chestnut parent or ever produces chestnut, it is Ee or ee. The birth color is very important, if it is known. A gray born chestnut has ee, and one born bay is Aa or AA. So you see that the codes can be determined with enough knowledge.
Now my stallion, Rahima, is a bay produced from two grays. So his code is ggA?E?. He has produced chestnut so he is ggA?Ee. He has also produced black so his total code is known as ggAaEe. Armed with this information, we can see that if we breed him to a homozygous black ggaaEE, we can not get either chestnut or gray. The only possible color combinations are Aa, Aa, aa, and aa. So the foal will have a 50-50 chance of being either bay or black. If bay, it will probably be a dark bay. If we breed him to a chestnut who has produced both bay and black (ggAaee) then there is a zero chance of gray (gg only), a 50% chance of chestnut (Ee, Ee, ee, and ee). Next dominant is bay and this possibility is (Aa, Aa, aa, and aa). So this is a 50% chance of the remaining 50% possibilities so .5 x .5=.25 or 25% chance of bay. The remaining probability is black at also 25%.
I have a bay mare so she is ggA?E?. She has a sister who is a chestnut so both parents carried the recessive chestnut gene. That gives my mare a good chance of being Ee. One grandparent was black so she has a 50% chance of having a black gene. She has very dark shoulder and other points so I think she does carry the black gene. I cannot be sure yet, but I think she is ggAaEe. If I cross them, the possibilities are 0% gray (gg only), 25% chestnut, 9/16 bay (about 56%), and 19% black. With practice, you can do it in your head.
I hope this has been of interest to you. As an engineer, I can get a bit carried away with the math. What is really important is the phenotype and not color, but when you are waiting 11 months it makes the winter pass easier with something to keep you busy.


Now all we need to know is what everyone's pony is genetically! LOL!

I'll let you know when I've worked mine through!

[zeldalithgow]

[lucydales]

I have translated it into mating two blacks genetically and you get a 95% chance black, 5% chestnut!

So what are "brown" ponies genetically? Are they the same as bays??

Come on Zelda, this is good for exercising your grey matter!! LOL!!

Let's work through Leia and Bill's possibilities!

[zeldalithgow]

Lucy I don't think I've got much left that works ;D

Leia is black but a browny/black with auburn highlights to her mane and tail

[Debbie]

LOL....I'll take a stab at Blossom's then and see. Her mum is grey, and I'm not sure if she's thrown black foals or not....so G? LOL As for Blossom's sire, he's black so that's ggaaE? Did I get that right??

Blossom herself was put down as a black in her passport, but has remained a pretty solid bay colouring. Soooo we have the possibility of Gg or ggAa with her...and yes, I shortened it because I got a bit muddled.

At least it makes sense when I went through reading the charts. LOL, my science teacher couldn't fault me for that at least