A Colour Genetics Guide

MatHalTed

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I have a deep interest in Equine Colour Genetics and recently did a presentation on it for my Uni degree, so thought I would share the guide I made here. Most information is from UC Davis, combined with what I've learned from my studying. Enjoy lol:

The Base Coats:

The two basic coat colours of horses include chestnut, and black. Bay is created due to interactions between these 2 genes, so is not necessarily considered to be a base coat. These are controlled by the interaction between 2 genes: Melanocortin 1 Receptor (MC1R) and Agouti Signaling Protein (ASIP).

MC1R, more commonly referred to as the Extension or red factor locus, is responsible for determining whether a horse will have a chestnut base coat colour or a black or a bay base coat colour. The Extension gene has an autosomal recessive mode of inheritance, meaning that the gene causing the trait is located on a non-sex chromosome & that 2 copies of a variant allele are needed to express the trait.

Mode of Inheritance: Autosomal recessive

Alleles:
E = Dominant Extension (red factor) allele
e = Recessive Extension (red factor) allele

Horses with E/E genotype will be capable of producing black pigment and cannot transmit the recessive Extension allele to their offspring, so cannot produce Chestnut offspring. They will be Bay or Black, depending on their Agouti status, and if there are any other colour modifying genes present. This is sometimes referred to as 'Homozygous Black', however a horse can be Bay and have Homozygous Extension alleles, so this is a slightly inaccurate term.

Horses with E/e genotype will be capable of producing black pigment. They will be Bay or Black, depending on their Agouti status, and if there are any other colour modifying genes present. They may transmit the dominant Extension allele (E) to 50% of their offspring, and may transmit the recessive Extension allele (e) to 50% of their offspring.

Horses with e/e genotype will not produce black pigment in their coat. They will be Chestnut, regardless of their Agouti status, unless there are any other colour modifying genes present. They will transmit a recessive Extension allele to all of their offspring.

ASIP, more commonly referred to as the Agouti gene, controls the distribution of black pigment and determines whether a horse will have a bay or black base coat colour. The Agouti gene has an autosomal dominant mode of inheritance, meaning that the gene causing the trait is located on a non-sex chromosome & that only 1 copy of the variant allele is needed to express the trait.

Mode of Inheritance: Autosomal dominant

Alleles:
A = Dominant Agouti allele (responsible for bay)
a = Recessive Agouti allele (causes black)

If black pigment is present in the form of at least 1 copy of the dominant Extension allele, horses with A/A genotype will have black pigment restricted to the ‘points’. As long as the horse is not homozygous recessive for Extension, they will be Bay, unless other colour modifying genes are present. They will transmit the dominant Agouti allele to all of their offspring.

If black pigment is present, in the form of at least 1 copy of the dominant Extension allele, horses with A/a genotype have black pigment restricted to the ‘points’. As long as the horse is not homozygous recessive for Extension, they will be Bay, unless other colour modifying genes are present.
They will transmit the dominant Agouti allele to 50% of their offspring and the recessive Agouti allele to 50% of their offspring.

If black pigment is present, in the form of at least 1 copy of the dominant Extension allele, horses with a/a genotype will have black pigment distributed evenly uniformly over the body. They will be Black, unless other colour modifying genes are present, and will transmit the recessive Agouti allele to all of their offspring.


Bay: Bay horses have a reddish-brown coat colour, with black points (mane, ear tips, tail and lower legs) and dark skin. Bay is caused by the Agouti Gene in combination with the Red Factor Gene meaning that all bay horses have a black base coat affected by one copy of the Agouti gene. Bay is the most common coat colour present in domestic equines and there are multiple colour variations of it, such as dark bay, red bay & light bay. Some consider it to be a base coat colour alongside chestnut and black, however this is debatable as bay is derived from black and not a colour in of itself. Bay can be genetically expressed as EE/AA, Ee/AA, EE/Aa & Ee/Aa

Black: Black horses have a solid black base coat spread uniformly over the entire body, mane & tail, dark brown eyes, and black skin. Sometimes if black horses are exposed to the elements ‘sun-bleaching’ will occur, resulting in a faded-reddish tinge to the coat, mane & tail. Black coats are caused by the Red Factor gene alongside an unrestricted Agouti gene. Black can be genetically expressed as EE/aa & Ee/aa.

Chestnut: Chestnut horses have a reddish-brown coat colour with no black pigment present. The mane and tail can be the same shade of chestnut, or a lighter shade, as the body coat. There are multiple colour variations of chestnut, such as liver chestnut, which is a very dark red coat, and flaxen chestnut, which can be any shade of chestnut with a significantly lighter mane and tail. Chestnut is caused by two copies of the recessive red factor gene. Chestnut horses can be genetically expressed as ee/AA, ee/Aa & ee/aa. The Agouti gene will always be present on chestnut horses, but has no effect on the coat colour as it only controls black pigment.
 

MatHalTed

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The Cream and Pearl* Genes:
* Cream is far more common than Pearl is, (particularly in the UK) however as they are located on the same allele, and therefore can interact together, I will be including Pearl in this section.

Cream is a dominant dilution gene which means it will express even if only 1 copy of the gene is present, meaning that in its heterozygous form it will dilute the red pigment on the horse's coat, and in its homozygous form it will also dilute the black pigment, though its effect is not as strong.

Mode of Inheritance: Incomplete dominance

Alleles:
N = Normal or non-cream
Cr = Cream
N/N = No Cream allele
N/Cr = Heterozygous Cream allele (responsible for single dilutes such as Buckskin, Palomino & Smoky Black)
Cr/Cr = Homozygous Cream allele (responsible for double dilutes such as Perlino, Cremello & Smoky Cream)


Horses with the Cr/Cr genotype aka Double dilutes, (or Homozygous Creams) will always transmit 1 copy of the dominant Cream allele to all of their offspring.

Horses with the N/Cr genotype aka Single dilutes, (or Heterozygous Creams) will transmit 1 copy of the dominant Cream allele to 50% of their offspring and will not transmit the Cream allele to 50% of their offspring.
Horses with the N/N genotype will not be cream dilute and cannot transmit this cream dilution variant to their offspring.

Buckskin: Buckskin horses have a light-golden brown coat colour, with a black Mane/Tail & dark points. Buckskin horses are often incorrectly called ‘dun’ in the UK, despite the lack of a dorsal stripe and leg barring present in Dun horses. (Unless of course Nd1 is present, but we'll go into that later). Buckskin is the result of 1 copy (NCr)(is heterozygous) of the Cream dilution gene on a Bay base coat. 1 copy of the Cream dilution gene works only on the red pigment of the coat, turning the originally bay body a golden cream colour, but leaving the mane, tail and points black. Buckskin is genetically expressed as EE/AA/NCr, Ee/AA/NCr, EE/Aa/NCr & Ee/Aa/NCr.

Palomino: Palomino horses have a light-golden yellow coat with a pale white Mane/Tail. The Palomino coat colour is the result of a Chestnut horse carrying 1 copy (NCr)(is heterozygous) of the Cream Gene. As 1 copy of the Cream Gene dilutes only the red pigment, and as the Chestnut base colour does not express any black points, this results in both the coat colour and Mane/Tail colour being affected. Palomino is genetically expressed as ee/AA/NCr, ee/Aa/NCr & ee/aa/NCr.

Smoky Black: Smoky Black horses are virtually indistinguishable from true Black horses and, despite being less well-known than their golden counterparts, is also caused by the Cream dilution. The Smoky Black coat colour is the result of a Black horse carrying 1 copy (NCr) (is heterozygous) of the Cream Gene. As 1 copy of the Cream Gene dilutes only the red pigment, and the homozygous agouti gene results in unrestricted black pigment throughout the coat meaning there is no red pigment, the dilution is not present. Smoky Black horses can be slightly more prone to sun-bleaching than True Black horses, which can lead to them looking more like a Dark Bay or Seal Brown. Smoky Black is genetically expressed as EE/aa/NCr & Ee/aa/NCr.

Perlino: Perlino horses have a light, creamy coloured coat, with slightly darker points and a reddish tinted mane. They will always have blue eyes and pink skin. The Perlino coat colour is the result of a Bay horse carrying 2 copies (CrCr) (is homozygous) of the Cream Gene. Whilst 2 copies of the Cream Gene will dilute both the red pigment and the black pigment, it has less of an effect on the black pigment, which retains a little more colour, resulting in a reddish or rusty tint to the Mane/Tail and points. Perlino is genetically expressed as EE/AA/CrCr, Ee/AA/CrCr, EE/Aa/CrCr & Ee/Aa/CrCr.

Cremello: Cremello horses have a light, creamy coat and a slightly lighter cream/white mane and tail. They will always have blue eyes and pink skin. The Cremello coat colour is the result of a Chestnut horse carrying 2 copies (CrCr) (is homozygous) of the Cream Gene. 2 copies of the Cream Gene dilute the red pigment, which is the only pigment present on the Chestnut base coat, and create a pale creamy coat colour across the whole body. Cremello is genetically expressed as ee/AA/CrCr, ee/Aa/CrCr & ee/aa/CrCr.

Smoky Cream: Smoky Cream horses have a rusty-reddish cream, with an equally reddish cream Mane & tail. Like all other double dilutes, they will always have blue eyes and pink skin. The Smoky Cream coat colour is the result of a Black horse carrying 2 copies (CrCr) (is homozygous) of the Cream Gene. Whilst 2 copies of the Cream Gene will dilute both red and black pigment, it has less of an effect on the black pigment, which is why Smoky Cream horses are fractionally darker compared to the other double dilutes. Smoky Cream is genetically expressed as EE/aa/CrCr & Ee/aa/CrCr.

Pearl is a recessive allele meaning that it will only express in its true form when it has 2 copies (Prl/Prl) (is homozygous) of the gene. However it can interact with Cream as it is located on the same allele to produce a sort of "Pseudo-Double dilute" often known as Cream-Pearl.

Pearl is a rare coat colour dilution only found in a few breeds, such as the Lusitano, Pura Raza Espanola and American Quarter Horse, that is characterised by a dilution of the coat, mane, and tail as well as a lightening of the skin, often resembling the champagne dilution. It is only displayed when the horse has 2 copies of the gene, so horses that are heterozygous for the pearl genotype will not show the phenotype even though they are carriers, unless the Cream gene is also involved.

Mode of Inheritance: Autosomal recessive

Alleles:
N = Normal or non-pearl
Prl = Pearl
N/N = No Pearl allele
N/Prl = Heterozygous Pearl allele
Prl/Prl = Homozygous Pearl allele
Cr/Prl = Cream allele and Pearl allele interaction

Horses with the Prl/Prl genotype aka Homozygous Pearls will display the pearl coat colour and will transmit this pearl dilution variant to all of their offspring. However it will not express on the offspring unless there is another Pearl gene or a Cream gene present.

Horses with the N/Prl genotype aka Heterozygous Pearls will not display the pearl coat colour, but are carriers. They may transmit the pearl dilution variant to 50% of their offspring and will not transmit the pearl dilution variant to 50% of their offspring. Matings between 2 carriers (N/Prl) result in a 25% chance of producing pearl dilute offspring (Prl/Prl).

Horses with the N/N genotype will not display the pearl coat colour and will not transmit this pearl dilution variant to their offspring.

Horses with the Cr/Prl genotype will display a combination of Cream and Pearl characteristics, creating a Pseudo Double Dilute phenotype. The name for this colour is dependent on the horse's base coat for example a Chestnut with both a Cream and Pearl allele will be a Palomino Pearl. The horse will transmit a dominant Cream gene to 50% of all offspring and a recessive Pearl gene to 50% off all offspring.

Bay Pearl:
Two copies of the Pearl gene on a Bay base results in an apricot-coloured body similar to chestnut pearl, but with a darker brown mane, tail and points. Bay Pearl is genetically expressed as EE/AA/PrlPrl, Ee/AA/PrlPrl, EE/Aa/PrlPrl & Ee/Aa/PrlPrl.

Chestnut Pearl:
Two copies of the pearl gene on a Chestnut base results in a uniform light pink-apricot colour of the body, mane and tail. Chestnut Pearl is genetically expressed as ee/AA/PrlPrl, ee/Aa/PrlPrl & ee/aa/PrlPrl.

Black Pearl: Two copies of the Pearl gene on a Black base results in a light tan body with a darker mane, tail and points. Black Pearl is genetically expressed as EE/aa/PrlPrl & Ee/aa/PrlPrl.

Buckskin Pearl: A copy of the Pearl gene and a copy of the Cream gene on a Bay base result in a light apricot-coloured with a slightly darker reddish-brown mane, tail and points. Bay Pearl is genetically expressed as EE/AA/CrPrl, Ee/AA/CrPrl, EE/Aa/CrPrl & Ee/Aa/CrPrl.

Palomino Pearl: A copy of the Pearl gene and a copy of the Cream gene on a Chestnut base result in a pale apricot-coloured coat, with a slightly paler mane and tail. Palomino Pearl is genetically expressed as ee/AA/CrPrl, ee/Aa/CrPrl & ee/aa/CrPrl.

Smokey Black Pearl: A copy of the Pearl gene and a copy of the Cream gene on a Black base results in a pale tan body with a slightly darker mane, tail and points. Black Pearl is genetically expressed as EE/aa/CrPrl & Ee/aa/CrPrl.
 

MatHalTed

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Grey:
Grey is technically not a colour modifying gene but actually a dominant pigment disease which means it will express even if only 1 copy of the gene is present. It causes the base coat to progressively lighten as the horse ages, until it is eventually a pale white / grey. Because grey causes pigment to 'burn-out' quickly, it can frequently cause Melanoma. It also causes an overproduction of pigment at birth, resulting in Grey foals being born with an 'adult shade' of base coat, a lack of foal camouflage, hyperpigmentation and sometimes Grey 'goggles', however the latter is a less reliable indicator of Grey being present as certain other genes like Leopard Complex (LP) can also cause goggles.

Mode of Inheritance: Autosomal dominant

Alleles:
N = Normal or non-grey
G = Grey
N/N = No Grey allele
N/G = Heterozygous Grey allele
G/G = Homozygous Grey allele


Horses with the G/G genotype aka Homozygous Greys G/G will be grey and will transmit 1 copy of the dominant Grey allele to all of their offspring.

Horses with the N/G genotype aka Heterozygous Greys will be grey and will transmit 1 copy of the dominant Grey allele to 50% of their offspring and will not transmit the Grey allele to 50% of their offspring.

Horses with the N/N genotype will not be grey and will not pass the Grey gene to their offspring.

Grey will show up on and mask any base coat and any colour modifying genes present. It is known that sometimes an interaction between Dun and Roan when in conjunction with Grey can cause the Greying process to occur slower than it would without these colour modifying genes present, however it will still eventually burn out this pigment, producing a fully white-grey coat.
 

MatHalTed

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Dun: (Not to be confused with Buckskin)

Dun is a dominant allele meaning that it expresses whether it has 1 copy (D/nd2) (is heterozygous) of the gene or 2 copies (DD) (is homozygous) of the gene.
Dun is a coat colour dilution characterised by a lightening of the coat, similar to the cream gene in that it dilutes both red and black coat pigments, unlike cream however, the head, lower legs, mane, and tail remain undiluted. Oftentimes, dun is also characterised by ‘primitive markings’ such as a dark dorsal stripe, barring of the legs, shoulder stripes, and ‘cobwebbing’ on the forehead.
Other common features that Dun horses express are frosting of the mane/tail. The Dun gene is able to interact with all other coat colour alleles, similar to Grey.

Mode of Inheritance: Autosomal dominant

Alleles:
D = Dun dilute
nd1 = Non-dun 1 or dun factor*
nd2 = Normal or Non-dun 2
nd2/nd2 = Homozygous Non-dun2 or Normal
nd1/nd2 = Heterozygous Non-dun1 allele
nd1/nd1 = Homozygous Non-dun1 allele
D/nd1 = Heterozygous dun allele & Heterozygous Non-dun1
D/nd2 = Heterozygous dun
D/D = Homozygous Dun

Horses with the nd2/nd2 genotype will not be dun dilute and will not have primitive markings. They cannot transmit a dun dilution variant to their offspring.

Horses with the nd1/nd2 genotype will not be dun dilute, but may have primitive markings. They may transmit the non-dun1 variant to 50% of their offspring.

Horses with the nd1/nd1 genotype will not be dun dilute, but may have primitive markings. They will transmit the non-dun1 variants to all of their offspring.

Horses with the D/nd1 or D/nd2 will be dun dilute and will display primitive markings. They may transmit the dun dilute variant to 50% of their offspring.

Horses with the D/D genotype will be dun dilute and will transmit the dun dilute variant to all of their offspring. Matings with any genotype will produce dun dilute offspring.

*Non-dun1, aka dun factor, is not true dun, but it produces dun characteristics such as leg barring and dorsal stripes, and is why some horses without the dun gene have these factors. I'm not including it in the genotype listings below as it's a lot more writing and may be confusing lol.

Bay Dun: (Also known as Classic Dun) Bay dun horses are bay horses with either 1 or 2 copies of the Dun dilution gene. Bay dun horses are the most common type of dun, and have a tan or gold body with a black mane/tail and primitive markings, they can closely resemble buckskin horses (But are not the same and are not interchangeable.) Bay dun horses can be genetically expressed as Ee/Aa/Dnd2, EE/AA/Dnd2, EE/Aa/Dnd2, Ee/AA/Dnd2, Ee/Aa/DD, EE/AA/DD, EE/Aa/DD & Ee/AA/DD.

Red Dun: (Also known as Chestnut Dun) Red Dun horses are Chestnut horses with either 1 or 2 copies of the Dun dilution gene. Red dun horses have a light tan body with a darker reddish mane/ tail and primitive markings. Red dun horses can be genetically expressed as ee/Aa/Dnd2, ee/AA/Dnd2, ee/aa/Dnd2, ee/Aa/DD, ee/AA/DD & ee/aa/DD.

Grulla: (Also known as Grullo, Blue dun, Black dun or Mouse dun) Grulla horses are black horses with either 1 or 2 copies of the Dun dilution gene. Grulla horses have a blue-gray to mouse-brown coat with a black mane/tail and primitive markings. Grulla horses can be genetically expressed as EE/aa/Dnd2, Ee/aa/Dnd2, EE/aa/DD & Ee/aa/DD.

Dunalino: (Also known as Palomino Dun) Dunalino horses are Chestnut horses with 1 copy of the Cream gene and either 1 or 2 copies of the Dun gene. Dunalino horses have a creamy-golden coat with a white-flaxen mane/tail like Palomino horses do, however they will have a darker Dorsal stripe and primitive markings. Dunalino horses can be genetically expressed as ee/Aa/NCr/Dnd2, ee/aa/NCr/Dnd2, ee/AA/NCr/Dnd2, ee/Aa/NCr/DD, ee/aa/NCr/DD & ee/AA/NCr/DD.

Dunskin: (Also known as Buckskin Dun) Dunskin horses are Bay horses with 1 copy of the Cream gene and either 1 or 2 copies of the Dun gene. Dunskin horses have a creamy-golden coat with a black mane/tail and black points like Buckskin horses do, however they will have a darker dorsal stripe and primitive markings. Dunskin horses can be genetically expressed as Ee/Aa/NCr/Dnd2, Ee/AA/NCr/Dnd2, EE/Aa,NCr/Dnd2, EE/AA/NCr/Dnd2, Ee/Aa/NCr/DD, Ee/AA/NCr/DD, EE/Aa/NCr/DD & EE/AA/NCr/DD.

Smoky Grulla: (Also known as Smoky Black Dun) Smoky Grulla horses are black horses with 1 copy of the Cream gene and either 1 or 2 copies of the Dun gene. Smoky Grulla horses have a blue-gray to mouse-brown coat with a black mane/tail and primitive markings. Smoky Grulla is virtually indistinguishable from a traditional Grullo. Smoky Grulla horses can be genetically expressed as EE/aa/NCr/Dnd2, Ee/aa/NCr/Dnd2, EE/aa/NCr/Dnd2, Ee/aa/NCr/Dn2, EE/aa/NCr/DD, Ee/aa/NCr/DD, EE/aa/NCr/DD & Ee/aa/NCr/DD.

Perlino Dun: Perlino Dun horses are similar in colour to normal Perlino horses and will have pale blue-green eyes, but will have a slightly more diluted coat and will have very pale primitive markings that can be hard to distinguish from the rest of the coat. Perlino dun horses can be genetically expressed as Ee/Aa/CrCr/Dnd2, EE/AA/CrCr/Dnd2, EE/Aa/CrCr/Dnd2, Ee/AA/CrCr/Dnd2, Ee/Aa/CrCr/DD, EE/AA/CrCr/DD, EE/Aa/CrCr/DD & Ee/AA/CrCr/DD.

Cremello Dun: Cremello Dun horses are similar in colour to normal Cremello horses and will have pale blue-green eyes, but will have a slightly more diluted coat and will have very pale primitive markings that can be hard to distinguish from the rest of the coat. Cremello Dun horses can be genetically expressed as ee/Aa/CrCr/Dnd2, ee/aa/CrCr/Dnd2, ee/AA/CrCr/Dnd2, ee/Aa/CrCr/DD, ee/aa/CrCr/DD & ee/AA/CrCr/DD.

Smokey Cream Dun: Also known as Smokey Cream Grulla, they are again similar in colour to normal Smokey Cream horses and will have pale blue-green eyes, but will be slightly more diluted and will have primitive markings that can be hard to distinguish from the rest of the coat. Smokey Cream Dun horses can be genetically expressed as EE/aa/CrCr/Dnd2, Ee/aa/CrCr/Dnd2, EE/aa/CrCr/Dnd2, Ee/aa/CrCr/Dn2, EE/aa/CrCr/DD, Ee/aa/CrCr/DD, EE/aa/CrCr/DD & Ee/aa/CrCr/DD.
 

HopOnTrot

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🤯

I have a bay New Forest, I don’t know what colour her dam was but her sure was strawberry roan, she has white flecks in her coat and gets cream hair
 

HopOnTrot

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Sorry posted too soon!
She has light hairs in one of her legs like a blue roan and, especially in her winter coat, gets a lot of cream hairs around the tops of her legs.

Is she a true bay or some sort of crap roan? What causes roaning?
 

MatHalTed

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Champagne:
Champagne is a dominant allele meaning that it expresses whether it has 1 copy (N/Ch) (is heterozygous) of the gene or 2 copies (Ch/Ch) (is homozygous) of the gene. Champagne is a New World mutation, similar to Frame Overo, and is only found in horse breeds or horses crossed with ones from the Americas.

Champagne is a coat colour dilution responsible for diluting both red and black pigment as well as causing pinkish, freckles skin and amber / greenish coloured eyes. Whilst not on the same locus, Champagne can interact with the Cream gene, to produce a 'Cream Champagne' colour. For example a Chestnut horse with atleast 1 copy of the Champagne gene and 1 copy of the Cream gene results in a 'Gold Cream Champagne'.

Mode of Inheritance: Autosomal dominant

Alleles:
N = Normal or non-champagne
Ch= Champagne
N/N = No Champagne allele
N/Ch = Heterozygous Champagne allele
Ch/Ch = Homozygous Champagne allele

Horses with the Ch/Ch genotype aka Homozygous Champagne will be dilute and will transmit the Champagne dilution to all of their offspring.

Horses with the N/Ch genotype aka Heterozygous Champagnes will be dilute and will transmit 1 copy of the dominant Champagne allele to 50% of their offspring and will not transmit the Champagne allele to 50% of their offspring.

Horses with the N/N genotype will not be champagne dilute and cannot transmit the champagne dilution variant to their offspring.

Amber Champagne: Amber Champagne horses are Bay horses with either 1 or 2 copies of the Champagne gene. Amber champagne horses have a metallic golden-tan coat with a dark brown mane/tail & points. They have pinkish skin with freckles and amber, hazel or greenish eyes. An Amber Champagne horse could be genetically expressed as EE/AA/NCh, Ee/AA/NCh, EE/Aa/NCh, Ee/Aa/NCh, EE/AA/ChCh, Ee/AA/ChCh, EE/Aa/ChCh & Ee/Aa/ChCh.

Classic Champagne: Classic Champagne horses are black horses with either 1 or 2 copies of the Champagne gene. Classic Champagne horses have a metallic lilac tan or smoky brown coat, with a darker mane/tail & points. They have pinkish skin with freckles and amber, hazel or greenish eyes. A Classic Champagne horse could be genetically expressed as EE/aa/NCh, Ee/aa/NCh, EE/aa/ChCh & Ee/aa/ChCh.

Gold Champagne: Gold Champagne horses are chestnut horses with either 1 or 2 copies of the Champagne gene. Gold champagne horses resemble palominos, having a metallic golden coat with a golden-flaxen mane & tail. They, like all other Champagne horses, have pinkish skin with freckles and amber, hazel or greenish eyes. A Gold Champagne horse could be genetically expressed as ee/AA/NCh, ee/Aa/NCh, ee/aa/NCh, ee/AA/ChCh, ee/Aa/ChCh & ee/aa/ChCh.

Amber Cream Champagne: a bay-based coat with one Cream allele and at least one Champagne allele. The skin and eyes have champagne traits such as skin mottling, while the coat is a pale buff color. The points are a soft, pale grayish-chocolate. Amber Cream Champagne horses can genetically be EE/AA/NCr/NCh, Ee/AA/NCr/NCh, EE/Aa/NCr/NCh, Ee/Aa/NCr/NCh, EE/AA/NCr/ChCh, Ee/AA/NCr/ChCh, EE/Aa/NCr/ChCh & Ee/Aa/NCr/ChCh.

Classic Cream Champagne: a black-based coat with one Cream allele and at least one Champagne allele. Like an amber cream, they retain champagne traits in the skin and eyes, and range from pale buff to pale, almost lilac chocolatey-gray. Even though the coat is black-based, the mane and tail tend to be darker. Classic Cream Champagne horses can be genetically expressed as EE/aa/NCr/NCh, Ee/aa/NCr/NCh, EE/aa/NCr/ChCh & Ee/aa/NCr/ChCh.


Gold Cream Champagne: a chestnut-base coat with one Cream allele and at least one Champagne allele. The champagne traits remain in the skin and eyes, and the coat is an all-over ivory color, with a slightly paler mane and tail. Gold Cream Champagne horses can be genetically expressed as ee/AA/NCr/NCh, ee/Aa/NCr/NCh, ee/aa/NCr/NCh, ee/AA/NCr/ChCh, ee/Aa/NCr/ChCh & ee/aa/NCr/ChCh.


Perlino Champagne: A Bay base coat with two copies of the Cream gene and either one or two copies of the Champagne gene. They are a very pale ivory colour, with a slightly darker mane, tail and points. They have mottled skin and very pale blue-green eyes. The three double Cream dilutes when combined with Champagne produce coats that are virtually indistinguishable from each other. Perlino Champagne horses can be genetically expressed as EE/AA/CrCr/NCh, Ee/AA/CrCr/NCh, EE/Aa/CrCr/NCh, Ee/Aa/CrCr/NCh, EE/AA/CrCr/ChCh, Ee/AA/CrCr/ChCh, EE/Aa/CrCr/ChCh & Ee/Aa/CrCr/ChCh.

Smokey Cream Champagne: A Black base coat with two copies of the Cream gene and either one or two copies of the Champagne gene. They are a very pale ivory colour, with a slightly darker mane and tail. They have mottled skin and very pale blue-green eyes. The three double Cream dilutes when combined with Champagne produce coats that are virtually indistinguishable from each other. Smokey Cream Champagne horses can be genetically expressed as EE/aa/CrCr/NCh, Ee/aa/CrCr/NCh, EE/aa/CrCr/ChCh & Ee/aa/CrCr/ChCh.

Cremello Champagne: A Chestnut base coat with two copies of the Cream gene and either one or two copies of the Champagne gene. They are a very pale ivory colour, with a slightly lighter mane and tail. They have mottled skin and very pale blue-green eyes. The three double Cream dilutes when combined with Champagne produce coats that are virtually indistinguishable from each other. Cremello Champagne horses can be genetically expressed as ee/AA/CrCr/NCh, ee/Aa/CrCr/NCh, ee/aa/CrCr/NCh, ee/AA/CrCr/ChCh, ee/Aa/CrCr/ChCh & ee/aa/CrCr/ChCh.
 

ester

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There is genetic Rn roan and roaning (ticking) that are not synonymous.
However Rn isn’t a specific identified gene so it exists as a marker test only.

Usually Rn had a typical pattern of v-markings on the legs and no roaning on the head. However not always 😅 some have more extensive roan and some ‘frosty’ roans have it concentrated over the dorsal/top of tail only (and test positive for Rn)
 

MatHalTed

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Sorry posted too soon!
She has light hairs in one of her legs like a blue roan and, especially in her winter coat, gets a lot of cream hairs around the tops of her legs.

Is she a true bay or some sort of crap roan? What causes roaning?
Could you attach pictures? I think Roan is definitely in New Forest pony's so it's definitely a possibility, does she have 'inverted V markings' on her legs around knee / hock height? Also does her face remain solid? It could also be white ticking which can occur on most coat colours and isn't related to any specific genetics, or a Rabicano or Sabino type of White pattern
 

MatHalTed

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I'll be posting Silver and then the KIT mutations next, of which roan is one, I just need to find them in my doc as it's genuinely almost unnavigable lol.
 

FieldOrnaments

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White hairs in red pigmented areas are quite common. Moreso in chestnuts than bays but they do still happen on the bodies of bay horses. It's separate from roan though, roan is its own incomplete dominant gene that causes white (pigmentless) hairs through the body but not at the points, which is why they're sometimes called dark -headed roans.
I think the scattered white hairs are basically teeny tiny somatic mutations.

Sorry posted too soon!
She has light hairs in one of her legs like a blue roan and, especially in her winter coat, gets a lot of cream hairs around the tops of her legs.

Is she a true bay or some sort of crap roan? What causes roaning?
 

MatHalTed

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Silver:

Silver is a dominant allele meaning that it expresses whether it has 1 copy (N/Z) (is heterozygous) of the gene or 2 copies (Z/Z) (is homozygous) of the gene.

Silver is a coat colour dilution that dilutes black pigment. It does not affect red pigment so will not show up on any horses with a Chestnut base, whether they have other colour modifier genes present or not, but they can be hidden carriers of it. However it can work in conjunction with most other colour modifiers on Black and Bay base coats, for example a Bay with 1 Cream gene and atleast 1 Silver gene produces a Silver Buckskin. It is also associated with an inherited ocular syndrome known as Multiple Congenital Ocular Anomalies (MCOA)

Mode of Inheritance: Autosomal dominant

Alleles:
N = Normal or non-silver
Z = Silver; Multiple Congenital Ocular Anomalies (MCOA)
N/N = No Silver allele
N/Z = Heterozygous Silver allele
Z/Z = Homozygous Silver allele

Horses with the Z/Z genotype will be silver dilute and will transmit this silver dilution variant to all of their offspring. Matings with any genotype are predicted to produce silver foals. These horses will also likely have a more severe form of MCOA.

Horses with the N/Z genotype will be silver dilute and may transmit this silver dilution variant to 50% of their offspring. Matings with a N/N genotype will result in a 50% chance of producing a foal with the silver dilution. These horses will also likely have a less severe form of MCOA.

Horses with the N/N genotype will not have the silver dilution, or MCOA, and cannot transmit this silver dilution.

Silver Bay: A Bay horse with either 1 or 2 copies of the Silver gene. Silver Bay horses have a coat colour that remains the reddish body color typical of normal bays because the gene does not act on red pigment. But if the bay coat is dark, then it may show some dilution, and the presence of small amounts of silver gives them a chocolate appearance. The mane and tail are lightened to a white or sooty silver color. The legs can be diluted to a brownish-grey, mottled with whitish or silver hair. Silver Bay horses can be genetically expressed as EE/AA/NZ, Ee/AA/NZ, EE/Aa/NZ, Ee/Aa/NZ, EE/AA/ZZ, Ee/AA/ZZ, EE/Aa/ZZ & Ee/Aa/ZZ.

Silver Black: A Black horse with either 1 or 2 copies of the Silver gene. Silver Black horses have a coat colour that can range from creamy chocolate all the way to a chocolate brown or deep grey and often have dapples (rings of lighter hair). The mane and tail can vary from white to a sooty silver. But they can also be a chocolate color. Silver Blacks without dapples are called Chocolate Silver. They are often mistaken for flaxen liver chestnuts or sooty palominos. In Australia and New Zealand they are often called ‘Taffies’. Silver Black horses can be genetically expressed as EE/aa/NZ, Ee/aa/NZ, EE/aa/ZZ & Ee/aa/ZZ.

Silver Buckskin: A Bay horse with either 1 or 2 copies of the Silver gene and 1 copy of the Cream gene. Silver Buckskin horses have a coat colour that remains the golden body colour typical of normal buckskins because the gene does not act on red pigment. The mane and tail are lightened to a white or sooty silver color. The legs can be diluted to a pale brownish-grey, mottled with whitish or silver hair. Silver Buckskin horses can be genetically expressed as EE/AA/Ncr/NZ, Ee/AA/NCr/NZ, EE/Aa/NCr/NZ, Ee/Aa/NCr/NZ, EE/AA/NCr/ZZ, Ee/AA/NCr/ZZ, EE/Aa/NCr/ZZ & Ee/Aa/NCr/ZZ.

Silver Smokey Black: A Black horse with either 1 or 2 copies of the Silver gene and 1 copy of the Cream gene. Silver in combination with Cream on a Black base coat produces a unique coat colour that is described as looking like a 'Wet Paper Bag'. Silver Smokey Black horses have a coat colour that is an almost khaki brown-tan, with the mane and tail being a similar hue. Silver Smokey Black horses can be genetically expressed as EE/aa/NCr/NZ, Ee/aa/NCr/NZ, EE/aa/NCr/ZZ & Ee/aa/NCr/ZZ.

Silver Double Cream Dilutes: Silver isn't hidden on black based Double Cream dilutes like it is on Chestnut horses, however due to the effect of the double cream dilution, it is barely visible.
 

Pinkvboots

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I have a bay New Forest, I don’t know what colour her dam was but her sure was strawberry roan, she has white flecks in her coat and gets cream hair
My Louis is bay but gets grey through his coat when his shedding he also has light hairs on his legs so it is classed as a wild bay.
 

Cloball

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Grey:
Grey is technically not a colour modifying gene but actually a dominant pigment disease which means it will express even if only 1 copy of the gene is present. It causes the base coat to progressively lighten as the horse ages, until it is eventually a pale white / grey. Because grey causes pigment to 'burn-out' quickly, it can frequently cause Melanoma. It also causes an overproduction of pigment at birth, resulting in Grey foals being born with an 'adult shade' of base coat, a lack of foal camouflage, hyperpigmentation and sometimes Grey 'goggles', however the latter is a less reliable indicator of Grey being present as certain other genes like Leopard Complex (LP) can also cause goggles.

Mode of Inheritance: Autosomal dominant

Alleles:
N = Normal or non-grey
G = Grey
N/N = No Grey allele
N/G = Heterozygous Grey allele
G/G = Homozygous Grey allele


Horses with the G/G genotype aka Homozygous Greys G/G will be grey and will transmit 1 copy of the dominant Grey allele to all of their offspring.

Horses with the N/G genotype aka Heterozygous Greys will be grey and will transmit 1 copy of the dominant Grey allele to 50% of their offspring and will not transmit the Grey allele to 50% of their offspring.

Horses with the N/N genotype will not be grey and will not pass the Grey gene to their offspring.

Grey will show up on and mask any base coat and any colour modifying genes present. It is known that sometimes an interaction between Dun and Roan when in conjunction with Grey can cause the Greying process to occur slower than it would without these colour modifying genes present, however it will still eventually burn out this pigment, producing a fully white-grey coat.
Saw this paper about grey the other day thought it looked quite interesting.https://pubmed.ncbi.nlm.nih.gov/38571883/
White hairs in red pigmented areas are quite common. Moreso in chestnuts than bays but they do still happen on the bodies of bay horses. It's separate from roan though, roan is its own incomplete dominant gene that causes white (pigmentless) hairs through the body but not at the points, which is why they're sometimes called dark -headed roans.
I think the scattered white hairs are basically teeny tiny somatic mutations.
I don't think Rn is an incomplete dominant as @ester said it's a kit mutation
 

Celtic Jewel

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I think a cure for a buckskin incorrectly being called dun is literally just make people dna test their horses color gene so the results will be put in the passport it would stop the breeder’s breeding for color so they can get more money on calling a buckskin a dun.
 

MatHalTed

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I think a cure for a buckskin incorrectly being called dun is literally just make people dna test their horses color gene so the results will be put in the passport it would stop the breeder’s breeding for color so they can get more money on calling a buckskin a dun.
Agreed, we need an UK version of UC Davis as the colour testing options available over here aren't as accurate, and it's a pain having to ship to the States. I might try suggesting something like that to my Uni tbh.
 

ycbm

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I think a cure for a buckskin incorrectly being called dun is literally just make people dna test their horses color gene so the results will be put in the passport it would stop the breeder’s breeding for color so they can get more money on calling a buckskin a dun.


It's what it looks like that makes it worth more money, not what name anyone gives the colour. Duns and buckskins both carry a premium over the same horse in bay.
.
 

FieldOrnaments

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they offer basically the same tests as UC I think. I can't admit to having used them though.
 

Backtoblack

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Can anyone help. My pony, unknown breeding but likely a mix of Shetland/trotter/and feathered cob is black but with red hairs in his mane and tail. He's around 11 hh. My other horse is around 16hh,is welsh cob gypsy cob and heavy horse, possibly shire mix. He is black but often looks to be extremely dark liver chestnut and has definitely got black points. His dam was black and his sire chestnut and white skewbald. Are these two true black or something else. Thanks in advance.
 

ester

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Photos needed really, ‘true black’ has often been used to mean non fading black but it doesn’t have a genetic basis.

As general info the best way to tell black v a very dark liver chestnut is the colour of the hair at the coronary bands
 

Backtoblack

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Photos needed really, ‘true black’ has often been used to mean non fading black but it doesn’t have a genetic basis.

As general info the best way to tell black v a very dark liver chestnut is the colour of the hair at the coronary bands
Thanks I'll take a look
 
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