Equine Coat Color Genetics

Lesson Four

Dun and Champagne

The Dun and the Champagne dilution genes are two entirely different, separate genes, but they do have one thing in common – they are both in the “simple dominant” category. You will remember that this means that it takes only one copy of the gene to get a visible effect, and that there is no difference in appearance between heterozygous and homozygous (one copy or two). And unlike some other dilution genes, these two genes affect both red and black pigments, so they are expressed on any base color, and cannot “hide” on any of the base colors. Because they are dominant, they cannot skip generations; a dun horse must have at least one dun parent and a champagne horse must have at least one champagne parent. But there are occasions when the gene may not be visible. A horse that is also grey, for instance, will eventually look white, leaving no clue about its base color. Some pintos have so much white that the base color is impossible to determine. And some cases of multiple dilution genes make it hard to tell (i.e. a cremello or perlino probably will not show any visible signs of dun or champagne if they have it). In those cases, or if a horse could be homozygous, the test will be very useful.

The Dun gene

The Dun gene is one that affects both red and black pigment equally, lightening red hair to a peachy or pale-red shade and black hair to a mousy-grey or almost blue-grey tone. The skin and eye color are not diluted. (The dilution effect is thought by some to be caused by the pigment being restricted to one side of the hair shaft, rather than an actual lightening of the pigment itself, but this theory is not proved or disproved yet.) Dun is unlike any of the other dilution type genes in that it is "location-specific"; that is, it dilutes the hair on the body, but leaves the points (lower legs, mane, tail) undiluted. It also is unique in that it causes various markings that are collectively referred to as "dun-factor" or "dun-markings". These include a sharp, clear dorsal stripe, striping or “barring” on the upper legs, "frosting" on the outer edges of the mane and tail, "cobwebbing" (concentric circles of darker hair) on the forehead, white or light eartips, "zippers" (thin stripes of lighter colored hair running vertically down the back of the lower legs), and dark shading or striping over the withers and/or lower neck. There is often a darker "masking" on the face. All duns will have the dorsal stripe and leg barring at least, but the other markings are variable from one individual to another. Not all duns will have all of the markings, and non-duns can have some of them. Any color can have a dorsal stripe (believed to be caused by sooty or countershading) but a non-dun dorsal stripe has a different "look" and "character" to it than a dun dorsal stripe. It certainly can take some experience to tell then apart, though, and not all horses "follow the rules", so it's nice that there is now a test to tell dun from non-dun in those confusing cases. In the days when both true duns and buckskins were called “dun”, it was not uncommon to see the term “line-backed dun” used to refer to duns, with dorsal stripes.

The gene is one of the most recent to be found. There was a test for “markers” for it starting in 2008, which means they have almost narrowed it down but not quite. This test is available through U.C. Davis. In 2014 it was announced by Animal Genetics that they had found the causative mutation for the Dun gene, and they offer a test for it now. They have not published this information though, so some are not completely convinced. Time will tell.

Duns of all shades do not generally get dapples like the kind that appear on other colors. It is quite rare to find a dun with dapples (and most of those that do have them are both Cream and Dun). Duns, like champagnes, sometimes get "reverse dapples" -- darker spots rather than lighter ones, but these are not overly common either. Duns also, like champagnes, do not show "sooty" tones which are common on cream-dilutes and nondilutes. The theory is that since the gene dilutes both black and red pigments, the black "sootiness", if present, would be diluted enough that it would not stand out visually. Although dun shades, like any color, can range from light to dark, the dilution cannot be "hidden" by black hair the way a cream-dilute can.

Not all breeds have the Dun gene. Some of the most common breeds do not have dun, most notably the Thoroughbred and Arabian, and most Warmbloods. Even in breeds where it occurs, it is not a very common color. Many of the American breeds do carry dun, including the QH and derivative breeds (Paint, Appy, POA), the Mustang, and most of the gaited breeds (TWH, MFT, Paso) although it is very rare in those. Note that in many breeds it is quite common to call buckskins "dun" and therefore you should never presume a horse registered as dun is actually dun, especially in British breeds (i.e. Connemara, Welsh, TB). The only drafter breed known to come in dun is the Mulassier.

How it works

Dun on a chestnut base color is called Red Dun. In times past it was also called “Copper”, and the lightest shades of red dun are often called “Claybank” in some places.

They can range from a distinctive light peachy or apricot tone to a darker shade that could pass for a sunbleached or bodyclipped chestnut at first glance. The points are left undiluted, so are whatever shade of red the horse would have been if it didn't have the Dun gene. The dun-factor markings are also red.

Typical chestnut/sorrel: e/e, any agouti, d/d

Dun on chestnut – Red Dun: e/e, any agouti, D/_

Dun on a bay base color is most often just called Dun, but also Bay Dun, Zebra Dun, Yellow Dun, and sometimes less common terms like "peanut-butter dun" (a pretty accurate description of the typical body color) and "buckskin dun" (meaning a dun that looks like a buckskin; not a genetically correct term -- if taken literally, that term would mean a horse with both a Cream gene and a Dun gene).

They look similar to a buckskin, with yellowish bodies and black points. But the body tone generally tends to be more "flat" or "earth-toned" and less golden than a buckskin. Since both colors can have a wide range of shades, the best way to tell them apart is to look for the dun-markings. Although a buckskin may have a dorsal stripe, strong leg barring is diagnostic of dun. (In cases where there is still some doubt, genetic testing can now sort out the buckskins, duns, and dunskins.) The dun-factor markings on a bay dun will be whatever color the hair would have been in that place without any dilution -- typically a dark red for the dorsal stripe and any wither/neck stripes/shadows, and leg barring that is dark red higher up the leg and black closer to the knees/hocks.

Typical bay: E/_, A/_, d/d

Dun on bay – Dun or Bay Dun: E/_, A/_, D/_

Dun on a black base color is usually called Grulla (the Spanish word for Crane, pronounced “grew-ya”), sometimes spelled Grullo, or in some places, Black Dun, Mouse Dun, or Blue Dun. Some breeders call an exceptionally light, silvery-toned one a “silver grulla”, but this is not genetically correct (there is a separate gene named Silver, so it should not be used as a descriptive term).

They have a greyish body color, but unlike a grey, which when examined closely is a mixture of dark and white hairs, a grulla's hairs are all the same greyish color. It can tend toward a tannish shade in some horses but is usually a "cool" tone tending more toward bluish. A sunbleached smoky black can do a very good grulla imitation, but they are usually more yellowish in tone. The grulla's dun-factor markings will be black.

Typical black: E/_, a/a, d/d

Dun on black - Grulla: E/_, a/a, D/_

Dun on a seal brown base color does not have a specific official name (and is not recognized as a separate color by any registry), but is generally called Brown Dun or sometimes Seal Dun by those who have one. The ones on a darker base shade would look like a grulla with the tan muzzle of a seal brown, but would most likely be registered as grulla. The ones on a lighter base shade would look like a darker shade of bay dun, and these have been called "Lobo Dun" or “Olive Dun” in some places. In the past these would have been hard to identify, but now that there is a test for Seal Brown, they can be distinguished from other duns. We do not have a picture of a confirmed brown dun at this time.

Breeding for these colors

With a simple dominant gene, it can be easy to get the color on your foal – just find a horse that is homozygous for Dun. Breeding such a horse to a non-dun would give you a heterozygous Dun foal every time:

Punnett Square example:

	D	D
d	D/d	D/d
d	D/d	D/d

Breeding a heterozygous Dun horse to a non-dun would give you a 50-50 chance of a Dun foal:

Punnett Square example:

	D	d
d	D/d	d/d
d	D/d	d/d

Some close-ups of the “dun-factor” markings

(Photos provided courtesy of Cedar Ridge QH www.grullablue.com )

Dorsal stripe:

Leg barring:

Ear barring/tips:

Face mask:

Mottling on the forearm:

Neck striping:

Mane & tail frosting:

Cobwebbing:

Barbs (or fishboning) off the dorsal stripe:

The Champagne gene

Like Dun, Champagne is a simple dominant gene in the dilution category. Although for many years it was confused with Cream and Dun dilutes, it has been known to be a separate gene for at least a dozen years now. It's well understood at this point, and it's not particularly difficult to recognize a champagne, unless the horse has other genes that interfere with being able to see the color, such as grey, roan, large amounts of white, or combinations of multiple different dilution genes. In those cases it can be difficult or impossible to tell, so the test will be useful. Also, the test will identify homozygous champagnes. It has been observed that many of the homozygous champagnes are lighter in body color, and have pinker skin with fewer freckles than usual. However, the difference is not necessarily great enough to make them distinctly different looking, and it is not known yet whether this will hold true in every case.

The mutation that causes the Champagne gene was found in 2008 by a team at the University of Kentucky. A test is now available from various labs. You can read the research paper here:

http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1000195

The Champagne gene affects both red and black pigment equally, lightening red hair to a golden shade (quite similar to palomino) and black hair to a sort of greyish-to-chocolate tone depending on the individual. And, unlike most of the other color-modifying genes, champagne also affects the skin and eye color. The defining characteristic of champagnes of all types and shades is pink skin. They are born with bright pink skin and bright blue eyes. Over time the eyes usually change to greenish, hazel, amber or light brown. The skin darkens to a more dusky sort of pink, and develops dark freckles which tend to increase with age and exposure to sun. Some horses get so many freckles on their muzzles and around the eyes that their skin could appear to be dark (especially in pictures), but on closer inspection the pink underneath the freckles is evident, and looking at the skin on the sheath or udder, and under the tail, will give a better idea of its true color without the sun exposure. The pink skin is a different color than the unpigmented pink skin that occurs under white markings -- champagnes with pinto markings illustrate that noticeably. If a blaze goes down over the nose, for example, the outline of the marking can be clearly seen. The white-marking pink skin is brighter pink, without any freckles (and tends to sunburn), and the champagne skin is slightly darker pink, with the freckles (and tends not to sunburn).

Champagnes of all shades do not generally get dapples like the kind that appear on other colors. It would be very, very rare to find a champagne with dapples (and the few that have been seen are usually both cream and champagne). They often get what are called "reverse dapples" -- darker spots rather than lighter ones. Not all champagnes get them, and they come and go with the seasons. Reverse dapples are not unique to champagnes, but seen only rarely on other colors. Champagnes also do not show "sooty" tones which are common on cream-dilutes and non-dilutes. There may exist one somewhere, but a "sooty" champagne has never yet been documented. The theory is that since the gene dilutes both black and red pigments, the black "sootiness", if present, would be diluted enough that it would not stand out visually. Champagnes tend to have a very even body color, the same shade all over, without the lighter and darker shading that is common on many other colors. They also often have a metallic sheen to their coats. Not all champagnes have this, and plenty of non-champagnes have it too, so it's not a defining characteristic of the color, but it is fairly common, especially in summer coats. Champagnes often have faint dorsal stripes that come and go, but they are nothing like a true dun dorsal stripe.

One unusual thing about this color is that foals are usually born much darker than they will end up when mature, which is the exact opposite of most foal colors. Typically, the foal's color looks like what it would have been without any dilution gene -- like a bay foal, for example, with an amber champagne. The combination of a coat that doesn't look diluted, with the bright-pink skin and blue eyes, is quite striking. Then, when they shed out in a few months, they lighten up to their normal adult champagne color. It can be quite a dramatic change. The interesting thing is that some foals are born already diluted, and don't change much when they shed. It's not as common, but it does happen, and nobody knows yet why.

There is a color registry for champagnes, the ICHR, founded in 2000. They have a very informative website at http://www.ichregistry.com/ which is highly recommended to anyone wanting to learn more about the color. You can see pictures of all the registered horses, which display a tremendous variety of colors and shades; and their pedigrees, with the champagne lines indicated. You can see what breeds have the color, and which bloodlines are champagne. There are also close-ups of all the champagne characteristics, which is helpful in identifying them when you come across one. Not all breeds have the Champagne gene. Some of the most common breeds do not have it, such as the Thoroughbred, Arabian, and Morgan. Even in breeds where it occurs, it is not a very common color. It can be hard to know for sure, since they have historically (and usually even today) been registered as something else, i.e, palomino or dun. It is known to exist today in the American gaited breeds such as ASB, TWH, MFT, and so on; the stock type breeds such as the Quarter Horse, Paint, Appaloosa, and so on; in Minis and grade ponies; in the American Cream Draft; and it has been introduced to a few Warmblood breeds via those that allow some outside blood (typically a small amount of QH or Saddlebred).

How it works

Champagne on a chestnut base color is called Gold Champagne, or just Gold. They look very much like palominos with golden bodies and white manes and tails. Occasionally the mane and tail are not white, but the same shade as the body (this is commonly called a "self gold") or even somewhat darker. The body color ranges from light gold to dark gold, but they don't have the same extreme shade range as palominos do. Typically they have been registered as palomino or "golden", depending on breed, but some have been registered as sorrel (presumably they were registered before the foal-coat shed out). The ones with darker manes and tails were probably thought to be red dun.

Typical chestnut/sorrel: e/e, any agouti, ch/ch

Champagne on chestnut - Gold champagne: e/e, any agouti, Ch/_

Champagne on a bay base color is called Amber Champagne, or just Amber. They look similar to a buckskin or dun at first glance, with golden bodies and dark points. The mane and tail are usually not black, but a dark bronze to chocolate sort of shade. The legs may be darker from the knees and hocks down (although not truly black) but often they are not much darker than the body. Manes and tails often have "frosting", or lighter hairs along the outer edges. They are typically registered as buckskin or dun.

Typical bay: E/_, A/_, ch/ch

Champagne on bay – Amber champagne: E/_, A/_, Ch/_

Champagne on a black base color is called Classic Champagne, or just Classic. They are the most unusual shade of all. The color is hard to describe, a sort of greyish brownish, nearly purplish at times, similar to grulla at other times. This is probably the color that was called "lilac dun" by the old-timers. Many have likened it to a Weimaraner dog. The manes and tails are generally darker, and the legs may or may not be darker than the body, but there is no true black hair anywhere. Historically they have most often been registered as grulla or dun, but there are many odd examples of classic champagnes being registered as all kinds of strange colors, including chestnut and brown. It seems that nobody knew quite what to call them!

Typical black: E/_, a/a, ch/ch

Champagne on black – Classic champagne: E/_, a/a, Ch/_

Champagne on a seal brown base color is called Sable Champagne, or just Sable. The darker ones look pretty much the same as a Classic Champagne, and the lighter ones look like an Amber. Without testing them to see which agouti genes they have, it can be impossible to tell them apart. The only registry to recognize it as a separate color is the ICHR. Most others call them dun, grulla, or buckskin, whichever the registry thinks it most resembles.

Champagne on brown – Sable champagne: E/_, At/At or At/a, Ch/_

Breeding for these colors

With a simple dominant gene, it can be easy to get the color on your foal – just find a horse that is homozygous for Champagne. Breeding such a horse to a non-dilute would give you a heterozygous Champagne foal every time:

Punnett Square example:

	Ch	Ch
ch	Ch/ch	Ch/ch
ch	Ch/ch	Ch/ch

Breeding a heterozygous Champagne horse to a non-dilute would give you a 50-50 chance of a Champagne foal:

Punnett Square example:

	Ch	ch
ch	Ch/ch	ch/ch
ch	Ch/ch	ch/ch

Some Close-ups of the Champagne Characteristics

Pictures provided courtesy of the International Champagne Horse Registry http://www.ichregistry.com/index.htm

Pink skin with dark freckles: The skin will be this color everywhere except under pure white markings.

Best seen on udder/sheath or under tail:

Eye color: Eye color in Champagnes will vary from an Amber color to almost a green color – foals are often born with an Aqua or Teal colored eye which will change to Amber or a green hue as the foal ages.

An Amber eye A Teal or Green eye

Reverse dapples:

Champagne with dark dapples Compare to…………………. Bay with light dapples

Click Here To Take Quiz - Duns and Champagnes