Smoky black

Smoky black or black carrying cream is a coat color of horses which has the same phenotype as black. Smoky black is produced by the action of a heterozygous (single copy) cream gene on an underlying black coat color.^[1] Therefore, smoky black is a member of the cream family of coat color dilutions, and found in horse populations that have other cream-based colors such as palomino, buckskin, perlino, cremello and smoky cream. All smoky blacks must have at least one parent with the cream gene, and a smoky black can only be verified through DNA testing or parentage. Smoky black has been mistaken for faded black, dark bay or brown, grullo or even liver chestnut.^[2]

A single copy of the cream gene can have a subtle effect on the colour of an otherwise black horse.^[3] However, this cannot be used to positively identify an individual horse as black or smoky black, as too much variation comes from other sources. An individual black horse may well be a lighter shade than an individual smoky black horse, even if the reverse is more common. Other factors that can influence the shade of black and smoky black horses include sun fading and nutrition.

Two copies of the cream gene on a black base coat produce a smoky cream, a cream-colored horse which cannot be visually distinguished from a perlino or cremello, but can be identified through DNA testing.

Appearance

Smoky black horses can range from a pure black color to a lighter color resembling bay. The palest can be mistaken for dull bays or liver chestnuts, especially if exposed to the elements. Bleaching due to the elements means that the legs retain their color better, and can take on an appearance of having dark points like a bay horse.^[4]

While it superficially resembles other coat colors, experienced horse persons often detect something "off" about the coat of an adult smoky black. The darkest shades among smoky blacks are almost indistinguishable from true black but for a slightly burnished look often chalked up to sun bleaching. The palest can be mistaken for dull bays or liver chestnuts, especially if exposed to the elements. Smoky black coats tend to react strongly to sun and sweat, and many smoky blacks turn to a brown color with particularly reddish tips of the manes and tails. Bleaching due to the elements means that the legs retain their color better, and can take on an appearance of having dark points like a bay horse. Smoky blacks, however, will lack rich red tones in the coat, instead favoring brown and orange tones.^[5]

Smoky black horses, like other horses with a single copy of cream, often have slightly lighter eyes and skin than non-cream horses. Their eye color may be amber even at adulthood.^[6] However, it is sometimes difficult to distinguish an amber-brown eye from an ordinary dark brown eye unless there are other horses available for direct comparison.

Like black foals, smoky black foals are typically quite silvery, and may be mistaken for grullos, especially when born with primitive markings. Smoky black foals are sometimes born with reddish tufts of hair in their ears, again like black foals.

Identification

There is no reliable way to be certain that a horse is smoky black through purely visual identification, because it can so closely resemble black or bay.

Although the single copy of cream can slightly affect the shade of black, this subtle effect cannot be used to confirm a horse as either black or smoky black. For an analogy, consider humans. Men are on average taller than women, and yet if you only know someone's height, that does not tell you their gender.

Some genetically palomino horses may be such a dark shade that they could be mistaken for smoky black.^[7]

By genetic test

A smoky black horse will test as having one copy of the cream gene, two copies of the recessive a allele at agouti, and one or two copies of the dominant E allele at extension.

By parentage

Smoky black horses must always have at least one parent with the cream dilute allele and at least one parent with the E allele of extension. Additionally, both parents must have at least one copy of the a allele of agouti. If these conditions are not met, the horse is definitely not smoky black.

If one parent is a double dilute cream (such as cremello, perlino, or smoky black), then absent mutations the foal is guaranteed to inherit at least one copy of the cream gene. In this case, the horse is definitely not black and must be palomino, buckskin, smoky black, or another cream-based color.

Glóbrúnn

Among Icelandic horses, some horses with the genetics expected of smoky black are a noticeably lighter color, a shade of reddish-brown called "glóbrúnn" or "muskóttur".^[8] It is believed this color is caused by one or more additional genetic modifiers that change the appearance when cream is also present.^[9]

Smoky black mimics

Dark bay: When smoky blacks fade from exposure to the elements, their legs usually retain their color, giving them the appearance of a bay or brown horse with black points. However, the brown coat of a bleached smoky black recalls orange rather than red or mahogany.
Black: A black horse without cream may still develop a sun-bleached coat, usually due to issues related to management and nutrition, though in some cases there may also be genetic factors contributing. A smoky black looks very similar to a sun-bleached black, and often only pedigree analysis or genetic testing can distinguish between the two.
Seal brown: The just off-black coat color of true seal browns can sometimes be misidentified as smoky black, or vice versa.
Liver chestnut: The palest, most evenly bleached smoky blacks may mimic the darkest shades of chestnut. Chestnuts will usually show reddish tones around the fetlocks. Smoky blacks usually have uniformly black legs. Furthermore, most chestnuts do not possess amber eyes.
Classic champagne: Paler smoky blacks with amber eyes may be confused with the activity of champagne on a black coat. Champagne horses have pinkish, freckled skin and green, hazel or amber eyes, as opposed to the dark skin and brown or amber eyes of a smoky black.
Grullo: Grullo is the action of the dun gene on black. Typically, grullo coats have cool slate hues as opposed to warm orange-brown tones. Furthermore, grullos have dun characteristics such as bold dorsal stripes and leg bars.

References

^ "Horse Coat Color", Veterinary Genetics Lab, University of California, Davis. Web Site accessed May 29, 2008
^ Sponenberg, D. Phillip; Bellone, Rebecca (2017). Equine Color Genetics (4 ed.). p. 97. One rare horse color, which is usually missed as being part of the cream-related group, is smoky. Smoky horses are best described as "off-black" and are only included in the discussion of these colors because they have important genetic ties to the cream-related colors. Smoky horses are usually a flat color that is not quite brown [defined on page 48 as bay with black countershading], not quite liver chestnut, and not quite black (Figure 4.28). The points are black, but observers sometimes miss the subtle differences between the point and body colors. Smoky horses are frequently registered as either brown or dark liver chestnut despite the black points. They frequently have hazel eyes. Smoky horses occur rarely, and only in breeds in which palomino and buckskin horses also occur. Because smoky horses are likely to be misregistered as another dark color, they can often produce surprises when buckskin or palomino foals are born. A few horses are smoky with yellow highlights in the flanks, muzzle, and around the eyes. These are essentially light seal brown horses, and can be called smoky seal to distinguish them from ordinary seal brown.
^ "Cream". UC Davis Veterinary Genetics Laboratory. Retrieved Sep 11, 2023.
^ Color and Markings Guidelines Accessed May 28, 2008.
^ Smoky Black Colorful Morgans. Accessed May 28, 2008.
^ Locke, MM; LS Ruth; LV Millon; MCT Penedo; JC Murray; AT Bowling (2001). "The cream dilution gene, responsible for the palomino and buckskin coat colors, maps to horse chromosome 21". Animal Genetics. 32 (6): 340–343. doi:10.1046/j.1365-2052.2001.00806.x. PMID 11736803. The eyes and skin of palominos and buckskins are often slightly lighter than their non-dilute equivalents.
^ "Palomino". Retrieved Sep 11, 2023.
^ Hafsteinsdóttir, Hera Sól (2022). Erfðabreytileiki í MC1R geninu í muskóttum (glóbrúnum) íslenskum hrossum (PDF) (Thesis). Landbúnaðarháskóli Íslands.
^ Sigurðardóttir, Ástrós (2012). Einangrun erfðavísis glólita í íslenska hestinum (PDF) (Thesis). Háskóli Íslands.

[1] "Horse Coat Color", Veterinary Genetics Lab, University of California, Davis. Web Site accessed May 29, 2008

[SponenbergBellone2017-2] Sponenberg, D. Phillip; Bellone, Rebecca (2017). Equine Color Genetics (4 ed.). p. 97. One rare horse color, which is usually missed as being part of the cream-related group, is smoky. Smoky horses are best described as "off-black" and are only included in the discussion of these colors because they have important genetic ties to the cream-related colors. Smoky horses are usually a flat color that is not quite brown [defined on page 48 as bay with black countershading], not quite liver chestnut, and not quite black (Figure 4.28). The points are black, but observers sometimes miss the subtle differences between the point and body colors. Smoky horses are frequently registered as either brown or dark liver chestnut despite the black points. They frequently have hazel eyes. Smoky horses occur rarely, and only in breeds in which palomino and buckskin horses also occur. Because smoky horses are likely to be misregistered as another dark color, they can often produce surprises when buckskin or palomino foals are born. A few horses are smoky with yellow highlights in the flanks, muzzle, and around the eyes. These are essentially light seal brown horses, and can be called smoky seal to distinguish them from ordinary seal brown.

[3] "Cream". UC Davis Veterinary Genetics Laboratory. Retrieved Sep 11, 2023.

[4] Color and Markings Guidelines Accessed May 28, 2008.

[5] Smoky Black Colorful Morgans. Accessed May 28, 2008.

[locke2007-6] Locke, MM; LS Ruth; LV Millon; MCT Penedo; JC Murray; AT Bowling (2001). "The cream dilution gene, responsible for the palomino and buckskin coat colors, maps to horse chromosome 21". Animal Genetics. 32 (6): 340–343. doi:10.1046/j.1365-2052.2001.00806.x. PMID 11736803. The eyes and skin of palominos and buckskins are often slightly lighter than their non-dilute equivalents.

[7] "Palomino". Retrieved Sep 11, 2023.

[8] Hafsteinsdóttir, Hera Sól (2022). Erfðabreytileiki í MC1R geninu í muskóttum (glóbrúnum) íslenskum hrossum (PDF) (Thesis). Landbúnaðarháskóli Íslands.

[9] Sigurðardóttir, Ástrós (2012). Einangrun erfðavísis glólita í íslenska hestinum (PDF) (Thesis). Háskóli Íslands.

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