Goat Color Genetics 101
I'm going to start this section with the caveat that goat color genetics do not seem to be understood nearly as well as rabbit or even cavy color genetics. Perhaps this shouldn't be surprising: goats have much smaller birth number (twins and occasional triplets, not litters), goats aren't usually used as experimental animals where scientists need to define everything about test subjects, and goats are usually bred for characteristics like meat, milk and fiber production -- where color is relatively unimportant. The information here is everything I've been able to find, but please assume it isn't complete. And if you have information I DON'T have here - please please send it my way!
Breeding decisions about goats (with the exception of fiber goats) should NOT be made on the basis of color. With the exception of a handful of color disqualifications (which should be rare if you stay within breed) color gets next to no points in the show ring. Nonetheless - I think it's fun to try to predict the color of babies. Don't be surprised to be surprised - as noted, the info here isn't complete.
Goats are also known for shifting colors - much more so than rabbits or cavies. Some of the genes (like ticked described below) definitely seem to cause color to change with age. And both eumelanin and phaeomelanin can change intensity with sunlight -- just like you getting a tan. This is known to cause pronounced seasonal changes in color in some goats. I highly recommend you observe your goat kid's color for a year before coming to a 'conclusion' about genetics (unless you have lots more info from pedigree, siblings, etc).
I'm going to open by introducing the two pigments (colored proteins) responsible for goat color. Rabbits and cavies have these same two proteins - eumelanin and phaeomelanin. In rabbits, eumelanin is responsible for what we called the base color - black, blue, chocolate and lilac. In rabbits phaeomelanin is responsible for the 'marking color' - shades from pale tan to red. White portions of the rabbit coat have no pigments (no phaeomelanin and no eumelanin). In cavies, things got a bit more tricky, with the 6 base colors - black, slate, lilac, chocolate, beige and caramel thanks to eumelanin and the phaeomelanin ranging from cream to dark red. Goats aren't so much harder, but they are more confusing. In goats the eumelanin ranges from black to chocolate to red while the phaeomelanin ranges from a color so pale it looks white to golds to a dark red-brown. See the problem? In goats, both eumelanin AND phaeomelanin can look red-brown! It's confusing to refer to the two portions of the coat as the dark part (or black part) and the light part (or tan part) when they aren't really necessarily those colors at all and the 'dark part' is often lighter than the 'light part.' Also, in goats very frequently most of the coat color is due to phaeomelanin and the 'markings' are the eumelanin -- so it just seems wrong to me to refer to the eumelanin as the 'base color'. So I'm just going to call them eumelanin and phaeomelanin.
Breeding decisions about goats (with the exception of fiber goats) should NOT be made on the basis of color. With the exception of a handful of color disqualifications (which should be rare if you stay within breed) color gets next to no points in the show ring. Nonetheless - I think it's fun to try to predict the color of babies. Don't be surprised to be surprised - as noted, the info here isn't complete.
Goats are also known for shifting colors - much more so than rabbits or cavies. Some of the genes (like ticked described below) definitely seem to cause color to change with age. And both eumelanin and phaeomelanin can change intensity with sunlight -- just like you getting a tan. This is known to cause pronounced seasonal changes in color in some goats. I highly recommend you observe your goat kid's color for a year before coming to a 'conclusion' about genetics (unless you have lots more info from pedigree, siblings, etc).
I'm going to open by introducing the two pigments (colored proteins) responsible for goat color. Rabbits and cavies have these same two proteins - eumelanin and phaeomelanin. In rabbits, eumelanin is responsible for what we called the base color - black, blue, chocolate and lilac. In rabbits phaeomelanin is responsible for the 'marking color' - shades from pale tan to red. White portions of the rabbit coat have no pigments (no phaeomelanin and no eumelanin). In cavies, things got a bit more tricky, with the 6 base colors - black, slate, lilac, chocolate, beige and caramel thanks to eumelanin and the phaeomelanin ranging from cream to dark red. Goats aren't so much harder, but they are more confusing. In goats the eumelanin ranges from black to chocolate to red while the phaeomelanin ranges from a color so pale it looks white to golds to a dark red-brown. See the problem? In goats, both eumelanin AND phaeomelanin can look red-brown! It's confusing to refer to the two portions of the coat as the dark part (or black part) and the light part (or tan part) when they aren't really necessarily those colors at all and the 'dark part' is often lighter than the 'light part.' Also, in goats very frequently most of the coat color is due to phaeomelanin and the 'markings' are the eumelanin -- so it just seems wrong to me to refer to the eumelanin as the 'base color'. So I'm just going to call them eumelanin and phaeomelanin.
The Eumelanin Color Gene - B
Same gene as in rabbits and cavies - the one that codes for making the pigment protein eumelanin. In rabbits and cavies, this gene has only two forms - B is black and b is brown. Goats have more options! Four alleles (forms of the gene) have been described for the B-gene in goats. These are:
Bd = dark brown aka chocolate brown. This is the most dominant gene of the series.
Bl = light brown aka milk chocolate. This gene is recessive to dark brown, but dominant over the following.
B+ = black. This is the 'normal' or 'wild type' form of melanin and the most common allele found in goats.
b = liver aka recessive red, aka medium brown. I prefer to call this gene 'eumelanin red' as there is another recessive gene that can also cause red color in goats AND because the resulting color really looks red to my eyes - not brown. But since you are probably already irritated with me for making you read words like eumelanin over and over, I promise to call it 'liver red'.
Although there are 4 alleles, remember that each goat has AT MOST two of these in its gene pair. It gets one from it's mother and one from it's father. For those of you who jumped straight here without learning the other species genetics first (totally understandable if you don't have rabbits or cavies!) let's step through the combinations.
Every goat gets one B-gene from each parent - one from its mother and one from its father. So every goat has two B genes. They can be the same allele, or they can be two different ones. If they are the same, it is obvious what color you get - it is the only one there. If they are different, you have to figure out how they interact to form the color you see. In a gene like B that shows complete dominance, only the more dominant of those two genes can be seen and the other is completely hidden. Therefore...
BdBd, BdBl, BdB+, and Bdb will all look the same = dark brown. The sources I got this information from tell me that this color can be very very dark and even appear black at birth, but usually lightens in the first few weeks. So don't jump to conclusions that the genetics must be wrong if you see a black baby when the theory said dark brown. Give it some time. Actually, that's a good rule with all the goat colors as many of them are known to shift quite a bit in the first year.
BlBl, BlB+, and Blb will all look the same = light brown.
B+B+ and B+b are black.
and finally
bb is liver red.
I have a pedigreed angora buck at my house whose papers read light brown, but to me he looks really red and I think he is actually liver red -- based on what I see and on what I was told he has sired previously. Eagerly awaiting first kids to see if I am right. Which goes to say that the gradations of color between black, dark brown, medium brown and light brown can be really difficult to distinguish.
Please note that black gene B+ will not hide chocolate genes Bd or Bl.
For the folks coming to this from rabbits, this is going to be the dead opposite of what you expect! The chocolate allele in rabbits is NOT AT ALL the same as the chocolate allele in goats -- even though they are both modifications to the B gene and both affect the shape of the eumelanin protein. In rabbits, chocolate is recessive. In goats, chocolate is dominant. Bugs my nice logical mind, but that's the way it is. It also seriously bugs my logical mind that the 'medium brown' is the recessive to the series rather than between the dark and light browns in dominance and that black is stuck in the middle of the browns. But the logic only works if you break it all the way down to protein synthesis and the refraction of light -- which is more complicated than I want to get. Better to just memorize the order: dark>light>black>medium/red
For the folks who have goats and those wanting to understand goat genetics - THIS gene says that you shouldn't ever get a chocolate baby out of two black parents. If you get an apparently chocolate baby out of two blacks, something else is going on. That 'something else' isn't an impossibility or a miracle or a mutation - just a different gene or gene interaction that we will get to in a bit.
Bd = dark brown aka chocolate brown. This is the most dominant gene of the series.
Bl = light brown aka milk chocolate. This gene is recessive to dark brown, but dominant over the following.
B+ = black. This is the 'normal' or 'wild type' form of melanin and the most common allele found in goats.
b = liver aka recessive red, aka medium brown. I prefer to call this gene 'eumelanin red' as there is another recessive gene that can also cause red color in goats AND because the resulting color really looks red to my eyes - not brown. But since you are probably already irritated with me for making you read words like eumelanin over and over, I promise to call it 'liver red'.
Although there are 4 alleles, remember that each goat has AT MOST two of these in its gene pair. It gets one from it's mother and one from it's father. For those of you who jumped straight here without learning the other species genetics first (totally understandable if you don't have rabbits or cavies!) let's step through the combinations.
Every goat gets one B-gene from each parent - one from its mother and one from its father. So every goat has two B genes. They can be the same allele, or they can be two different ones. If they are the same, it is obvious what color you get - it is the only one there. If they are different, you have to figure out how they interact to form the color you see. In a gene like B that shows complete dominance, only the more dominant of those two genes can be seen and the other is completely hidden. Therefore...
BdBd, BdBl, BdB+, and Bdb will all look the same = dark brown. The sources I got this information from tell me that this color can be very very dark and even appear black at birth, but usually lightens in the first few weeks. So don't jump to conclusions that the genetics must be wrong if you see a black baby when the theory said dark brown. Give it some time. Actually, that's a good rule with all the goat colors as many of them are known to shift quite a bit in the first year.
BlBl, BlB+, and Blb will all look the same = light brown.
B+B+ and B+b are black.
and finally
bb is liver red.
I have a pedigreed angora buck at my house whose papers read light brown, but to me he looks really red and I think he is actually liver red -- based on what I see and on what I was told he has sired previously. Eagerly awaiting first kids to see if I am right. Which goes to say that the gradations of color between black, dark brown, medium brown and light brown can be really difficult to distinguish.
Please note that black gene B+ will not hide chocolate genes Bd or Bl.
For the folks coming to this from rabbits, this is going to be the dead opposite of what you expect! The chocolate allele in rabbits is NOT AT ALL the same as the chocolate allele in goats -- even though they are both modifications to the B gene and both affect the shape of the eumelanin protein. In rabbits, chocolate is recessive. In goats, chocolate is dominant. Bugs my nice logical mind, but that's the way it is. It also seriously bugs my logical mind that the 'medium brown' is the recessive to the series rather than between the dark and light browns in dominance and that black is stuck in the middle of the browns. But the logic only works if you break it all the way down to protein synthesis and the refraction of light -- which is more complicated than I want to get. Better to just memorize the order: dark>light>black>medium/red
For the folks who have goats and those wanting to understand goat genetics - THIS gene says that you shouldn't ever get a chocolate baby out of two black parents. If you get an apparently chocolate baby out of two blacks, something else is going on. That 'something else' isn't an impossibility or a miracle or a mutation - just a different gene or gene interaction that we will get to in a bit.
The Phaeomelanin Color Genes - Rufus factor
Rufus factor controls the color of phaeomelanin. Unfortunately, it isn't a single gene, but a series of similar genes. In rabbits and cavies we discussed phaeomelanin as a minor modifier. While it is the same gene series, and works pretty much the same in all three species, rufus factor is MUCH more important in determining goat color. In goats, phaeomelanin ranges all the way from a cream so pale it looks white to our eyes - through true creams, tans, golds and apricots - to true orange-reds and even a deep red-brown.
While the chemical basis is somewhat more complicated, rufus factor acts as an additive gene series. I usually symbolize it as 5 gene pairs (I have no idea how many pairs are actually involved, likely that varies by species - and I would guess that goats have FAR more than rabbits as goats have a much broader color range) for a total of 10 genes in each animal. Each gene can be symbolized by a + (darker color) or a - (lighter color).
++++++++++ thus symbolizes a goat that has the darkest possible red-brown phaeomelanin color.
- - - - - - - - - - symbolizes a goat that has the lightest possible white phaeomelanin color
+-+-+-+-+- or +++++----- are somewhere in between = tans, golds etc.
In general, if you cross two really dark red goats, you get a really dark red kid. If you cross two really light goats, you get a really light kid.
When you cross a really dark colored goat (++++++++++) with a really pale goat (----------) you get a color somewhere in between (+-+-+-+-+-+-+-+-+-+-).
If you cross two medium colored goats with similar genotypes -- e.g., (+++++-----) with (+++++-----) -- you get medium colored kids that pretty much match the parents.
BUT if you cross two medium-phaeomelanin colored goats with different genotypes -- e.g., (+++++-----) with (-----+++++) -- you get medium-phaeomelanin kids (+-+-+-+-+-+-+-+-+-+-) ==> but it may be a strikingly different shade such as apricot rather than tan.
AND if you cross two medium-phaeomelanin colored goats which are themselves crossbred -- e.g., (+-+-+-+-+-+-+-+-+-+-) with
(+-+-+-+-+-+-+-+-+-+-) -- you can theoretically get the whole spectrum back (though 90% will fall to the middle range).
While the chemical basis is somewhat more complicated, rufus factor acts as an additive gene series. I usually symbolize it as 5 gene pairs (I have no idea how many pairs are actually involved, likely that varies by species - and I would guess that goats have FAR more than rabbits as goats have a much broader color range) for a total of 10 genes in each animal. Each gene can be symbolized by a + (darker color) or a - (lighter color).
++++++++++ thus symbolizes a goat that has the darkest possible red-brown phaeomelanin color.
- - - - - - - - - - symbolizes a goat that has the lightest possible white phaeomelanin color
+-+-+-+-+- or +++++----- are somewhere in between = tans, golds etc.
In general, if you cross two really dark red goats, you get a really dark red kid. If you cross two really light goats, you get a really light kid.
When you cross a really dark colored goat (++++++++++) with a really pale goat (----------) you get a color somewhere in between (+-+-+-+-+-+-+-+-+-+-).
If you cross two medium colored goats with similar genotypes -- e.g., (+++++-----) with (+++++-----) -- you get medium colored kids that pretty much match the parents.
BUT if you cross two medium-phaeomelanin colored goats with different genotypes -- e.g., (+++++-----) with (-----+++++) -- you get medium-phaeomelanin kids (+-+-+-+-+-+-+-+-+-+-) ==> but it may be a strikingly different shade such as apricot rather than tan.
AND if you cross two medium-phaeomelanin colored goats which are themselves crossbred -- e.g., (+-+-+-+-+-+-+-+-+-+-) with
(+-+-+-+-+-+-+-+-+-+-) -- you can theoretically get the whole spectrum back (though 90% will fall to the middle range).
The pattern gene - A
The A-gene is the primary control on the distribution of eumelanin and phaeomelanin in mammal coats. That's true for rabbits, cavies AND goats. In other words, the A-gene tells you which parts of the goat are going to be the eumelanin color and which parts are going to be the phaeomelanin color. There ARE other genes (which we will get to a little further down) that can mess with or mask the expression of the A-gene (if you read the rabbit and cavy sections, you know extension genes, for example also move phaeomelanin around).
Folks new to genetics struggled with 3 alleles in rabbits (when each rabbit can at most only have 2 of the three). Cavies were similar, until we added the tan pattern as a 4th allele - and one that couldn't be simply placed in the dominance order. Prepare yourself - goats have AT LEAST TWENTY TWO different A alleles! Before you panic, remember, each individual goat is going to have at most 2 different alleles. Most breeds have only a couple of the possibilities that are common in that breed - so you can use that info as a guide as well.
The patterns described next are the patterns you expect to see if the A-gene pair is homozygous -- that is, if you have two copies of the same allele. I will follow that with a few examples of what happens with the heterozygous pairs (when you have two different alleles).
I gathered this information from a variety of different sources -- but the BEST info for the pattern gene was from http://www.goatspots.com/genetics.html. They have wonderful diagrams on their site -- which I didn't think would be ethical to 'borrow'. So until I get my own pictures [please send me some if you have photos of nice clean patterns!] you might want to pop over there!
The A-Alleles of goats
Solid Phaeomelanin (Awht) - aka Dominant white. This allele gives a goat which appears solid in the phaeomelanin color - white, gold, red, etc. Some research suggests that AwhtAwht is ALWAYS all white (regardless of rufus factor) and that Awht with different A-allele gives the other colors (gold to red). This might explain why the solid pale colors rarely breed true. However, it is equally likely that the breeds which commonly use the Awht gene to produce all-white goats also have all genes for low rufus (----------) while those that accept the other solid phaeomelanin colors are more likely to have a mixture of rufus factor genes (+-+-+-+-+-+-+-+-+-+-) which also would not breed true.
Light Sable (Alsb) - Primarily phaeomelanin with a light intermixing of eumelanin in an overlay (top half of the goat - frequently forming a 'hooded-cape' pattern of darker shade). Solid phaeomelanin facial stripes within the 'hood' and eumelanin stripes on the legs.
Sable (Asb) - Primarily phaeomelanin with a heavy intermixing of eumelanin in an overlay (top half of the goat - frequently forming a 'hooded-cape' pattern of darker shade). Solid eumelanin facial stripes within the 'hood', eumelanin stripes on the legs, euemelanin martingale (a 'rein-like' pattern forming a chest V extending up over the shoulders), partial eumelanin spine stripe.
Black mask (Abm) - aka abbreviated buckskin, primarily phaeomelanin. Eumelanin on the head, brisket, and spine. Phaeomelanin stripes in the otherwise black head.
Bezoar (A+) - phaeomelanin on the body, belly and facial stripes. Eumelanin on the head, shoulder stripe, spine and stripes on legs.
Caramel (Acr) - phaeomelanin on the body. Eumelanin on the head, incomplete spine stripe, lower legs, and belly.
Badgerface (Ab) - aka blackbelly, oberhasli. Phaeomelanin body. Eumelanin on the belly, spine, lower legs and facial stripes.
Tan sides (Ats) - phaeomelanin on the sides. Eumelanin head, belly, chest, wide spine stripe, and tail.
San Clemente (Asc) aka buckskin - Eumelanin on the front half, phaeomelanin on the rear half. Phaeomelanin face stripes on a eumelanin head. Phaeomelanin chest and legs. Eumelanin chevron on rear legs.
Repartida (Arp) aka cour noir - eumelanin front half, phaeomelanin rear half, eumelanin head without any phaeomelanin stripes, each leg with phaeomelanin on the front and eumelanin on the back. prominent eumelanin chevron on the rear legs.
Grey (Ag) aka blue - uniformly covered with a mix of phaeomelanin and eumelanin. From my reading, it appears that this gene always causes the phaeomelanin to turn white, regardless of rufus factor. THe belly may be slightly lighter (more white phaeomelanin) but otherwise this animal looks solid colored.
Striped Grey (Asg) - uniformly covered with a mix of phaeomelanin and eumelanin. From my reading, it appears that this gene always causes the phaeomelanin to turn white, regardless of rufus factor. Eumelanin martingale. White phaeomelanin ears, muzzle, eyebars and legs.
Agouti Grey (Aga) - uniformly covered with a mix of phaeomelanin and eumelanin. From my reading, it appears that this gene always causes the phaeomelanin to turn white, regardless of rufus factor. Eumelanin martingale, spine and legs.
Peacock (Apk) - usually responsible for cou clair, cou blanc, and two-tone chamoisee. Phaeomelanin front half, eumelanin rear half OR rear half may be an intermix of paheomelanin and eumelanin, eumelanin facial stripes distinctively both above and below the eyes, eumelanin lower legs.
Swiss (Asm) - responsible for the Toggenburg pattern. Eumelanin body including the belly. Phaeomelanin legs, ears and facial stripes.
Eyebar (Aeb) - eumelanin body. Phaeomelanin belly, legs, ears and wide face stripes.
Black and tan (At) - Eumelanin body. Phaeomelanin on belly, leg stripes, inside ears and thin facial stripes.
Fishy (Afsh) - Eumelanin body. Pheomelanin on the front half of the belly (back half and udder always eumelanin), medium face bars, stripe on back of legs continuous to the hoof.
Lateral stripes (Als) aka sundgau. Eumelanin body and most of belly. Phaeomelanin part of belly, front of legs, light face stripes.
Mahoghany (Am) aka bay. eumelanin and phaeomelanin evenly intermixed (unlike the greys, the phaeomelanin retains its rufus color), eumelanin on face, legs and often on thighs.
Red cheek (Arc) eumelanin with a phaeomelanin patch on each cheek.
Solid eumelanin (a) aka black/chocolate. Entire animal is the eumelanin color.
Interaction of the A-alleles - The A-alleles do not follow a pattern of simple dominance where one allele completely hides another. Instead, they are considered co-dominant, where the two alleles interact to form the final pattern. Fortunately, these interactions DO follow a very simple and straightforward rule... If the two genes of the pair disagree as to whether a particular part (e.g., the spine) should be eumelanin or phaeomelanin - phaeomelanin always wins. This is somewhat counterintuitive, as we tend to expect that the darker color (which is usually eumelanin, but not always) would 'cover' the lighter color. That is not the case here -- to repeat -- phaeomelanin is always the color you see. Incidentally, this rule also works 100% for the A-gene of both rabbits and cavies, and explains why the Aat pattern of cavies looks mostly like the agouti, but has pea spots!)
With 22 alleles, the total number of 2-allele combinations grows pretty fast -- 22! = 1,124,000,000,000,000,000,000 possible combinations! Obviously, I'm not going to go through them all. But let's try a few examples...
Awht with any other allele... Because 'phaeomelanin always wins' and the A allele makes the whole animal phaeomelanin, it acts as a dominant gene and can hide any other A allele.
a with any other allele .... Because 'eumelanin always loses' and the a allele tries to make the whole coat eumelanin, any gene it is paired with that calls for phaeomelanin is going to show up looking just fine. a acts as a true recessive completely hiding behind any other A-allele.
Let's try two common ones -- caramel (Acr) and badger face (Ab)... Both have a phaeomelanin body, so that stays. Both have eumelanin on the belly and lower legs, so that stays. Badgerface has a complete spine stripe of eumelanin while the spine stripe of caramel is incomplete -- phaeomelanin wins giving an incomplete spine stripe. Caramel calls for eumelanin on the head, while the badgerface has a mostly phaeomelanin head with eumelanin just in the facial stripes == phaeomelanin wins, so the head is phaeomelanin with eumelanin stripes. = end result is a kid that looks mostly like a badgerface, but the spine stipe is incomplete.
Let's try another one - Swiss marked (Asm) and SanClemente (Asc) -- The Asc allele puts phaeomelanin on the rear half, chest, legs, and face stripes. The Swiss marked doesn't add phaeomelanin anywhere else, so the result looks just like the SanClemete pattern.
And one more - Peacock (Apk) and San Clemente (Asc) - Peacock puts phaeomelanin on the front half except for facial stripes and the lower legs. SanClemente puts phaeomelanin on the rear half plus the legs and face stripes. Result is an all phaeomelanin coat which could easily be mistaken for Awht! (though very narrow face stripes could remain if the face stripes of the two aren't in exactly the same place - likewise a midband of eumelanin could remain if 'front half' and 'back half' don't coincide exactly).
I'm not going to give an example here with the greys -- mainly because I don't understand at all why the grey genes turn the phaeomelanin white. The pattern of phaeomelanin/eumelanin SHOULD follow the same rules for this gene...but I don't know whether the phaeomelanin will always turn white (acting as if that aspect of the gene is dominant) or whether the phaeomelanin will stay the rufus color -- potentially resulting in an intermixing of eumelanin and phaeomelanin that 'looks like' mahoghany. If/when I figure this out, I will add an example. If you know, drop me a line.
Hopefully my examples here work well to help you see how to figure out the pattern if you know the genes. Working the other way can be very tricky as many patterns are very similar and sometimes two pattern alleles overlapping can look like a different allele altogether.
Folks new to genetics struggled with 3 alleles in rabbits (when each rabbit can at most only have 2 of the three). Cavies were similar, until we added the tan pattern as a 4th allele - and one that couldn't be simply placed in the dominance order. Prepare yourself - goats have AT LEAST TWENTY TWO different A alleles! Before you panic, remember, each individual goat is going to have at most 2 different alleles. Most breeds have only a couple of the possibilities that are common in that breed - so you can use that info as a guide as well.
The patterns described next are the patterns you expect to see if the A-gene pair is homozygous -- that is, if you have two copies of the same allele. I will follow that with a few examples of what happens with the heterozygous pairs (when you have two different alleles).
I gathered this information from a variety of different sources -- but the BEST info for the pattern gene was from http://www.goatspots.com/genetics.html. They have wonderful diagrams on their site -- which I didn't think would be ethical to 'borrow'. So until I get my own pictures [please send me some if you have photos of nice clean patterns!] you might want to pop over there!
The A-Alleles of goats
Solid Phaeomelanin (Awht) - aka Dominant white. This allele gives a goat which appears solid in the phaeomelanin color - white, gold, red, etc. Some research suggests that AwhtAwht is ALWAYS all white (regardless of rufus factor) and that Awht with different A-allele gives the other colors (gold to red). This might explain why the solid pale colors rarely breed true. However, it is equally likely that the breeds which commonly use the Awht gene to produce all-white goats also have all genes for low rufus (----------) while those that accept the other solid phaeomelanin colors are more likely to have a mixture of rufus factor genes (+-+-+-+-+-+-+-+-+-+-) which also would not breed true.
Light Sable (Alsb) - Primarily phaeomelanin with a light intermixing of eumelanin in an overlay (top half of the goat - frequently forming a 'hooded-cape' pattern of darker shade). Solid phaeomelanin facial stripes within the 'hood' and eumelanin stripes on the legs.
Sable (Asb) - Primarily phaeomelanin with a heavy intermixing of eumelanin in an overlay (top half of the goat - frequently forming a 'hooded-cape' pattern of darker shade). Solid eumelanin facial stripes within the 'hood', eumelanin stripes on the legs, euemelanin martingale (a 'rein-like' pattern forming a chest V extending up over the shoulders), partial eumelanin spine stripe.
Black mask (Abm) - aka abbreviated buckskin, primarily phaeomelanin. Eumelanin on the head, brisket, and spine. Phaeomelanin stripes in the otherwise black head.
Bezoar (A+) - phaeomelanin on the body, belly and facial stripes. Eumelanin on the head, shoulder stripe, spine and stripes on legs.
Caramel (Acr) - phaeomelanin on the body. Eumelanin on the head, incomplete spine stripe, lower legs, and belly.
Badgerface (Ab) - aka blackbelly, oberhasli. Phaeomelanin body. Eumelanin on the belly, spine, lower legs and facial stripes.
Tan sides (Ats) - phaeomelanin on the sides. Eumelanin head, belly, chest, wide spine stripe, and tail.
San Clemente (Asc) aka buckskin - Eumelanin on the front half, phaeomelanin on the rear half. Phaeomelanin face stripes on a eumelanin head. Phaeomelanin chest and legs. Eumelanin chevron on rear legs.
Repartida (Arp) aka cour noir - eumelanin front half, phaeomelanin rear half, eumelanin head without any phaeomelanin stripes, each leg with phaeomelanin on the front and eumelanin on the back. prominent eumelanin chevron on the rear legs.
Grey (Ag) aka blue - uniformly covered with a mix of phaeomelanin and eumelanin. From my reading, it appears that this gene always causes the phaeomelanin to turn white, regardless of rufus factor. THe belly may be slightly lighter (more white phaeomelanin) but otherwise this animal looks solid colored.
Striped Grey (Asg) - uniformly covered with a mix of phaeomelanin and eumelanin. From my reading, it appears that this gene always causes the phaeomelanin to turn white, regardless of rufus factor. Eumelanin martingale. White phaeomelanin ears, muzzle, eyebars and legs.
Agouti Grey (Aga) - uniformly covered with a mix of phaeomelanin and eumelanin. From my reading, it appears that this gene always causes the phaeomelanin to turn white, regardless of rufus factor. Eumelanin martingale, spine and legs.
Peacock (Apk) - usually responsible for cou clair, cou blanc, and two-tone chamoisee. Phaeomelanin front half, eumelanin rear half OR rear half may be an intermix of paheomelanin and eumelanin, eumelanin facial stripes distinctively both above and below the eyes, eumelanin lower legs.
Swiss (Asm) - responsible for the Toggenburg pattern. Eumelanin body including the belly. Phaeomelanin legs, ears and facial stripes.
Eyebar (Aeb) - eumelanin body. Phaeomelanin belly, legs, ears and wide face stripes.
Black and tan (At) - Eumelanin body. Phaeomelanin on belly, leg stripes, inside ears and thin facial stripes.
Fishy (Afsh) - Eumelanin body. Pheomelanin on the front half of the belly (back half and udder always eumelanin), medium face bars, stripe on back of legs continuous to the hoof.
Lateral stripes (Als) aka sundgau. Eumelanin body and most of belly. Phaeomelanin part of belly, front of legs, light face stripes.
Mahoghany (Am) aka bay. eumelanin and phaeomelanin evenly intermixed (unlike the greys, the phaeomelanin retains its rufus color), eumelanin on face, legs and often on thighs.
Red cheek (Arc) eumelanin with a phaeomelanin patch on each cheek.
Solid eumelanin (a) aka black/chocolate. Entire animal is the eumelanin color.
Interaction of the A-alleles - The A-alleles do not follow a pattern of simple dominance where one allele completely hides another. Instead, they are considered co-dominant, where the two alleles interact to form the final pattern. Fortunately, these interactions DO follow a very simple and straightforward rule... If the two genes of the pair disagree as to whether a particular part (e.g., the spine) should be eumelanin or phaeomelanin - phaeomelanin always wins. This is somewhat counterintuitive, as we tend to expect that the darker color (which is usually eumelanin, but not always) would 'cover' the lighter color. That is not the case here -- to repeat -- phaeomelanin is always the color you see. Incidentally, this rule also works 100% for the A-gene of both rabbits and cavies, and explains why the Aat pattern of cavies looks mostly like the agouti, but has pea spots!)
With 22 alleles, the total number of 2-allele combinations grows pretty fast -- 22! = 1,124,000,000,000,000,000,000 possible combinations! Obviously, I'm not going to go through them all. But let's try a few examples...
Awht with any other allele... Because 'phaeomelanin always wins' and the A allele makes the whole animal phaeomelanin, it acts as a dominant gene and can hide any other A allele.
a with any other allele .... Because 'eumelanin always loses' and the a allele tries to make the whole coat eumelanin, any gene it is paired with that calls for phaeomelanin is going to show up looking just fine. a acts as a true recessive completely hiding behind any other A-allele.
Let's try two common ones -- caramel (Acr) and badger face (Ab)... Both have a phaeomelanin body, so that stays. Both have eumelanin on the belly and lower legs, so that stays. Badgerface has a complete spine stripe of eumelanin while the spine stripe of caramel is incomplete -- phaeomelanin wins giving an incomplete spine stripe. Caramel calls for eumelanin on the head, while the badgerface has a mostly phaeomelanin head with eumelanin just in the facial stripes == phaeomelanin wins, so the head is phaeomelanin with eumelanin stripes. = end result is a kid that looks mostly like a badgerface, but the spine stipe is incomplete.
Let's try another one - Swiss marked (Asm) and SanClemente (Asc) -- The Asc allele puts phaeomelanin on the rear half, chest, legs, and face stripes. The Swiss marked doesn't add phaeomelanin anywhere else, so the result looks just like the SanClemete pattern.
And one more - Peacock (Apk) and San Clemente (Asc) - Peacock puts phaeomelanin on the front half except for facial stripes and the lower legs. SanClemente puts phaeomelanin on the rear half plus the legs and face stripes. Result is an all phaeomelanin coat which could easily be mistaken for Awht! (though very narrow face stripes could remain if the face stripes of the two aren't in exactly the same place - likewise a midband of eumelanin could remain if 'front half' and 'back half' don't coincide exactly).
I'm not going to give an example here with the greys -- mainly because I don't understand at all why the grey genes turn the phaeomelanin white. The pattern of phaeomelanin/eumelanin SHOULD follow the same rules for this gene...but I don't know whether the phaeomelanin will always turn white (acting as if that aspect of the gene is dominant) or whether the phaeomelanin will stay the rufus color -- potentially resulting in an intermixing of eumelanin and phaeomelanin that 'looks like' mahoghany. If/when I figure this out, I will add an example. If you know, drop me a line.
Hopefully my examples here work well to help you see how to figure out the pattern if you know the genes. Working the other way can be very tricky as many patterns are very similar and sometimes two pattern alleles overlapping can look like a different allele altogether.
The Extension Gene - E
This is where things get weird -- for all three species honestly. Because the E-gene also messes with the phaeomelanin-eumelanin balance it can 'override' the A-gene patterns.
In goats we have a total of 3 alleles described for the E-gene. They don't cause 'new' patterns -- just alternative genetics for some colors we already have. If you know the genetics of your goats, these are no more difficult than the preceding genes - maybe easier. But if you know only color and are trying to figure out the genetics, these definitely make it harder.
The three alleles are:
Dominant black (ED) - this gene completely overrides the instructions of the A gene and makes the entire goat eumelanin. I've been unable to determine whether this gene is truly dominant black or just dominant eumelanin -- that is, I don't know whether or not it will also hide chocolate alleles of the B gene. This allele is extremely rare outside of black angoras (and the hybrid angora crossbreeds) - and not all that common in angoras either.
Wild type (E+) - this is the 'normal' allele that allows you to see all the other patterns. 99.9% of goats are E+E+ -- allowing you to completely ignore the E gene.
Recessive Red (Er) - aka uniform red. This allele causes the entire coat to shift to phaeomelanin. It appears to be subject to rufus factor, but the color tends to be richer than would be predicted from the parent's rufus factor (when the parents are only carriers) alone. Reds due to this gene are also reported to be less likely to 'fade' in the fleece (due to the dilution of pigments over the long fibers) of angoras. This gene is considered rare except in angora and Nubian.
The alleles of the E gene in goats follow simple dominance rules. ED> E+ >Er
In goats we have a total of 3 alleles described for the E-gene. They don't cause 'new' patterns -- just alternative genetics for some colors we already have. If you know the genetics of your goats, these are no more difficult than the preceding genes - maybe easier. But if you know only color and are trying to figure out the genetics, these definitely make it harder.
The three alleles are:
Dominant black (ED) - this gene completely overrides the instructions of the A gene and makes the entire goat eumelanin. I've been unable to determine whether this gene is truly dominant black or just dominant eumelanin -- that is, I don't know whether or not it will also hide chocolate alleles of the B gene. This allele is extremely rare outside of black angoras (and the hybrid angora crossbreeds) - and not all that common in angoras either.
Wild type (E+) - this is the 'normal' allele that allows you to see all the other patterns. 99.9% of goats are E+E+ -- allowing you to completely ignore the E gene.
Recessive Red (Er) - aka uniform red. This allele causes the entire coat to shift to phaeomelanin. It appears to be subject to rufus factor, but the color tends to be richer than would be predicted from the parent's rufus factor (when the parents are only carriers) alone. Reds due to this gene are also reported to be less likely to 'fade' in the fleece (due to the dilution of pigments over the long fibers) of angoras. This gene is considered rare except in angora and Nubian.
The alleles of the E gene in goats follow simple dominance rules. ED> E+ >Er
White Pattern Genes
Many, many separate genes can shut down production of eumelanin and phaeomelanin. All leave white spots, patches or even all white coats where no pigments are produced. Some of these genes produce clear predictable patterns and their genetics have been described clearly. Most are subject to other modifier genes that cause subtle shifts in the white pattern. Because multiple genes are involved, it is possible for a single goat to have more than one pattern - for example a many goats have both a belt (belted gene below) and a white spot on top of their head (star gene below).
Angora white (W) - this is a dominant gene which shuts down the production of eumelanin and phaeomelanin over the entire coat (though not the eyes - which remain the normal color). There is a very small degree of incomplete dominance in this gene, such that the heterozygous (Ww) may have black stripes of eumelanin in their horns and hoofs. This gene is almost universal in the white angoras and very common in the white angora crossbreeds. It is considered extremely rare in other breeds.
Random/piebald (s) - there may actually be multiple alleles at the S-gene (so careful selective linebreeding for a particular pattern could result in a pattern that breeds true) but for the most part they can be treated as a single recessive gene where the ss genotype gives random white patches.
Belted - This is a dominant gene resulting in a white belt around the middle. Size and placement of the belt are likely controlled by modifier genes. Partial belts can apparently also be caused by modifier genes as they can revert to full belts in the next generation (demonstrating that the dominant S gene was present even though the belt was partial.
Schwartzhal - white on the body only, not the head. Usually expresses as an all white body with a colored head. Common in Boer goats. Believe to be dominant.
Frosted - white on the muzzle and ears. Dominant. Very common in Nubians and pygmies
Roan (Rn) - this gene causes a scattering of white hairs in the coat color. This gene probably shows some degree of co-dominance with RnRn goats having more white than Rnrn ones. Often the amount of roaning (white) is less over the head and shoulders. While ticked animals (below) generally develop more color over time, roans either have a stable pattern or grow lighter.
Flowery - this gene causes small white spots -- generally less than a half-inch on adults. Generally, there are many more spots on the lower part of the goat, with the back remaining almost solid colored.
Goulet - this gene may have multiple alleles or extensive modifiers which create patterns ranging from very little white (minimal grade) to nearly white (maximal grade). It is also likely co-dominant such that animals with two copies of the allele are much lighter than those with only one copy. Minimal grade = ears mostly white, some white in the face, usually a white tail, and a few flank spots. Medium grade = white ears, face white except around the nose and eyes, ragged white on body. Maximal grade - nearly white with ragged colored patches but usually keeping the colored eye circles. First documented in Tennessee fainting goats.
Algarve - similar to the Dalmatian (below) except that the spots/flecks have ragged edges. Similar to the Goulet except that the ears are always colored even in very white individuals.
Dark Dalmatian - Light (often tan rather than white indicating incomplete shutdown of pigment production) body with dorsal stripe and colored flecks which reveal the underlying color/pattern. Probably recessive. One of a very few genes that can result in more than three colors (to white, eumelanin and phaeomelanin, it adds the 'faded' eumelanin and faded phaeomelanin)
Light Dalmatian (da) - aka Nigerian pattern. As the name indicates, this pattern is very common in Nigerians but rare outside that breed. Recessive. Nearly white goat revealing the underlying color/pattern only in the dorsal stripe, head, legs, and a few flecks on the upper portions of the body.
Cou noir - White hindquarters. Probably a dominant gene. This is NOT the only gene combination to result in a cou noir (black neck) goat. Goats with black front halfs and tan hindquarters (also called cou noir) do NOT have this gene. This gene can also create a goat that we would not call cou noir -- for example a goat with a red front half and white hindquarters.
Star aka white poll - A dominant gene resulting in a white star on the head and usually with a white tip to the tail. Almost universal in Nigerians, not uncommon in other breeds.
Colored Spots
Moon spots - random round spots which can be dark brown to cream but never true white or black. Moon spots often change color, lightening as the goat ages. The gene is considered dominant, but can be hidden if the spots happen to fall on portions of the coat that are similar in color or if there are only a few or very small spots. This is another of the VERY FEW genes that can result in more than 3 colors (eumelanin, phaeomelanin and white) in the coat.
Ticked - evenly distributed tiny colored spots on an otherwise white coat or within the white spots on a coat. There MUST be another gene present creating the white (any of the above white-spotting genes) in order for the ticking to be seen. Usually the ticking develops with age, often the first signs of ticking are only seen when the goat approaches a year old. End result can easily be confused with roan. This pattern is caused by a dominant gene. I have not been able to find documentation of the interaction of the ticked gene with particular white patterns nor of its potential interaction when multiple white genes are present. I have a nigerian doe who is dalmatian pattern -- nearly white when we got her at a few months old. She started developing ticking at about 8 months old. Now almost two, her ticking is very heavy - except for a very clear 'belt' of much lighter ticking. I believe this means she has the belted gene 'hiding' under the dalmatian white -- the ticking is coming in lighter in this area where it has to 'fight' two genes that are trying to make the coat white.
Barbari - sometimes also called Dalmatian, but not the same gene as the (nigerian) dalmatian patterns above. This gene is a modification which restores colored spots within white areas of the coat. These dark spots are present at birth (unlike ticking ,which develops). Easily confused with the (Nigerian) Dalmatian pattern, barbari is uncommon in nigerians.
Angora white (W) - this is a dominant gene which shuts down the production of eumelanin and phaeomelanin over the entire coat (though not the eyes - which remain the normal color). There is a very small degree of incomplete dominance in this gene, such that the heterozygous (Ww) may have black stripes of eumelanin in their horns and hoofs. This gene is almost universal in the white angoras and very common in the white angora crossbreeds. It is considered extremely rare in other breeds.
Random/piebald (s) - there may actually be multiple alleles at the S-gene (so careful selective linebreeding for a particular pattern could result in a pattern that breeds true) but for the most part they can be treated as a single recessive gene where the ss genotype gives random white patches.
Belted - This is a dominant gene resulting in a white belt around the middle. Size and placement of the belt are likely controlled by modifier genes. Partial belts can apparently also be caused by modifier genes as they can revert to full belts in the next generation (demonstrating that the dominant S gene was present even though the belt was partial.
Schwartzhal - white on the body only, not the head. Usually expresses as an all white body with a colored head. Common in Boer goats. Believe to be dominant.
Frosted - white on the muzzle and ears. Dominant. Very common in Nubians and pygmies
Roan (Rn) - this gene causes a scattering of white hairs in the coat color. This gene probably shows some degree of co-dominance with RnRn goats having more white than Rnrn ones. Often the amount of roaning (white) is less over the head and shoulders. While ticked animals (below) generally develop more color over time, roans either have a stable pattern or grow lighter.
Flowery - this gene causes small white spots -- generally less than a half-inch on adults. Generally, there are many more spots on the lower part of the goat, with the back remaining almost solid colored.
Goulet - this gene may have multiple alleles or extensive modifiers which create patterns ranging from very little white (minimal grade) to nearly white (maximal grade). It is also likely co-dominant such that animals with two copies of the allele are much lighter than those with only one copy. Minimal grade = ears mostly white, some white in the face, usually a white tail, and a few flank spots. Medium grade = white ears, face white except around the nose and eyes, ragged white on body. Maximal grade - nearly white with ragged colored patches but usually keeping the colored eye circles. First documented in Tennessee fainting goats.
Algarve - similar to the Dalmatian (below) except that the spots/flecks have ragged edges. Similar to the Goulet except that the ears are always colored even in very white individuals.
Dark Dalmatian - Light (often tan rather than white indicating incomplete shutdown of pigment production) body with dorsal stripe and colored flecks which reveal the underlying color/pattern. Probably recessive. One of a very few genes that can result in more than three colors (to white, eumelanin and phaeomelanin, it adds the 'faded' eumelanin and faded phaeomelanin)
Light Dalmatian (da) - aka Nigerian pattern. As the name indicates, this pattern is very common in Nigerians but rare outside that breed. Recessive. Nearly white goat revealing the underlying color/pattern only in the dorsal stripe, head, legs, and a few flecks on the upper portions of the body.
Cou noir - White hindquarters. Probably a dominant gene. This is NOT the only gene combination to result in a cou noir (black neck) goat. Goats with black front halfs and tan hindquarters (also called cou noir) do NOT have this gene. This gene can also create a goat that we would not call cou noir -- for example a goat with a red front half and white hindquarters.
Star aka white poll - A dominant gene resulting in a white star on the head and usually with a white tip to the tail. Almost universal in Nigerians, not uncommon in other breeds.
Colored Spots
Moon spots - random round spots which can be dark brown to cream but never true white or black. Moon spots often change color, lightening as the goat ages. The gene is considered dominant, but can be hidden if the spots happen to fall on portions of the coat that are similar in color or if there are only a few or very small spots. This is another of the VERY FEW genes that can result in more than 3 colors (eumelanin, phaeomelanin and white) in the coat.
Ticked - evenly distributed tiny colored spots on an otherwise white coat or within the white spots on a coat. There MUST be another gene present creating the white (any of the above white-spotting genes) in order for the ticking to be seen. Usually the ticking develops with age, often the first signs of ticking are only seen when the goat approaches a year old. End result can easily be confused with roan. This pattern is caused by a dominant gene. I have not been able to find documentation of the interaction of the ticked gene with particular white patterns nor of its potential interaction when multiple white genes are present. I have a nigerian doe who is dalmatian pattern -- nearly white when we got her at a few months old. She started developing ticking at about 8 months old. Now almost two, her ticking is very heavy - except for a very clear 'belt' of much lighter ticking. I believe this means she has the belted gene 'hiding' under the dalmatian white -- the ticking is coming in lighter in this area where it has to 'fight' two genes that are trying to make the coat white.
Barbari - sometimes also called Dalmatian, but not the same gene as the (nigerian) dalmatian patterns above. This gene is a modification which restores colored spots within white areas of the coat. These dark spots are present at birth (unlike ticking ,which develops). Easily confused with the (Nigerian) Dalmatian pattern, barbari is uncommon in nigerians.
Blue eyed gene
Blue eyes in goats is caused by a simple dominant gene. This allele is common only in angoras, nigerians and fainting goats.
Blue eyes in goats is NOT related to health or vision problems. It is NOT linked to the gene that causes goats to faint. It is NOT true albino (which is a specific recessive gene that shuts down all pigment production, including to the eyes resulting in pink eyes). It is NOT the recessive 'leucistic albino' of blue-eyed white tigers (which shuts down the ability of eumelanin to darken when exposed to light). It is NOT the vienna gene that gives blue eyed white rabbits (which shows through in vienna marks on carriers and IS linked to health problems). It is also NOT the same gene that causes blue eyes in humans (blue eyes is recessive in humans). It is its own gene. It just makes the eyes blue - nothing else.
Blue-eyes is a dominant gene. A homozygous blue-eyed goat (with two copies of the allele) passes the gene to all its offspring and they will all have blue eyes - regardless of the eye color of the other parent. A heterozygous blue-eyed goat (carrying the more common allele for brown eyes) will give the gene to half its kids so at least half the kids from a blue-eyed goat would be expected to also have blue eyes.
Blue eyes in goats is NOT related to health or vision problems. It is NOT linked to the gene that causes goats to faint. It is NOT true albino (which is a specific recessive gene that shuts down all pigment production, including to the eyes resulting in pink eyes). It is NOT the recessive 'leucistic albino' of blue-eyed white tigers (which shuts down the ability of eumelanin to darken when exposed to light). It is NOT the vienna gene that gives blue eyed white rabbits (which shows through in vienna marks on carriers and IS linked to health problems). It is also NOT the same gene that causes blue eyes in humans (blue eyes is recessive in humans). It is its own gene. It just makes the eyes blue - nothing else.
Blue-eyes is a dominant gene. A homozygous blue-eyed goat (with two copies of the allele) passes the gene to all its offspring and they will all have blue eyes - regardless of the eye color of the other parent. A heterozygous blue-eyed goat (carrying the more common allele for brown eyes) will give the gene to half its kids so at least half the kids from a blue-eyed goat would be expected to also have blue eyes.