Rabbit Colour Genetics
I have found learning about the genetics behind breeding rabbits fascinating, so have decided to start a section on my site about rabbit colour genetics for anyone who is interested and also to help me learn more along the way!
First of all it is important to take it slowly, one step at a time when learning about this subject as it can seem a little confusing at first. But if you take it slowly, you will get there in the end!
A rabbit’s coat colour is mainly determined by five genes; A, Agouti B, black/brown C, colour saturation D, colour dilution and E, colour extension.
There are also other gene sets that include V -the Vienna gene responsible for blue eyed whites and En, the broken gene that gives you broken coloured rabbits - aka, butterfly’s
Each parent donates one of a pair of each type of gene to the kits in the litter. The kits inherit two of each gene; one from each parent. Dominant genes are expressed and are the colour you can visually see. This is known as the rabbits phenotype. Where as recessive genes are carried to be possibly passed on to offspring. This is known the rabbits genotype.
(what the genes are, Aa_BB etc)
Each gene, regardless of its dominance or recessive quality, is passed on to roughly half of the offspring.
First of all it is important to take it slowly, one step at a time when learning about this subject as it can seem a little confusing at first. But if you take it slowly, you will get there in the end!
A rabbit’s coat colour is mainly determined by five genes; A, Agouti B, black/brown C, colour saturation D, colour dilution and E, colour extension.
There are also other gene sets that include V -the Vienna gene responsible for blue eyed whites and En, the broken gene that gives you broken coloured rabbits - aka, butterfly’s
Each parent donates one of a pair of each type of gene to the kits in the litter. The kits inherit two of each gene; one from each parent. Dominant genes are expressed and are the colour you can visually see. This is known as the rabbits phenotype. Where as recessive genes are carried to be possibly passed on to offspring. This is known the rabbits genotype.
(what the genes are, Aa_BB etc)
Each gene, regardless of its dominance or recessive quality, is passed on to roughly half of the offspring.
The agouti gene
The A gene is expressed in three ways, A, which is responsible for an Agouti, at -tan which is responsible for otters and foxes and a, which is the self gene. The A - agouti gene is the most dominant of the three, followed by the at -tan gene and lastly a - self which is the most recessive.
For example if the Dam is aa - self and the sire is AA - Agouti, the offspring would all be Agouti type rabbits carrying the recessive self gene, which would look like this Aa. They are visually agouti rabbits but as they inherit one of a pair from each parent they will all carry the self gene as a recessive.
However, another possible combination could be Dam -Aa visual agouti carrying self and Sire aa -self the resulting kits in the litter would be Aa agouti carrying self and also aa -self.
The statistic probability of self vs. Agouti coloured offspring in the litter would be 50/50. The way I see it is if one parent is agouti but carries self and the other parent is self it balances the dominant agouti gene and gives an equal chance of getting self kits in your litter.
For example if the Dam is aa - self and the sire is AA - Agouti, the offspring would all be Agouti type rabbits carrying the recessive self gene, which would look like this Aa. They are visually agouti rabbits but as they inherit one of a pair from each parent they will all carry the self gene as a recessive.
However, another possible combination could be Dam -Aa visual agouti carrying self and Sire aa -self the resulting kits in the litter would be Aa agouti carrying self and also aa -self.
The statistic probability of self vs. Agouti coloured offspring in the litter would be 50/50. The way I see it is if one parent is agouti but carries self and the other parent is self it balances the dominant agouti gene and gives an equal chance of getting self kits in your litter.
The Black/Brown gene
This is quite an easy gene to remember, there are only two genes in this set, Black and brown (chocolate)
Colours that are in the (B) Black set include black, sooty fawn, blue and black chinchilla.
Colours that are in the chocolate set include chocolate, lilac, choc tort, choc chinchilla and lynx.
As there are only two genes in this set there are only three possible combinations BB. Bb and bb
The (B) black gene being the most dominant and (b) chocolate the recessive.
Therefore, a black rabbit can carry chocolate (the b gene) which would appear like this Bb, but a chocolate rabbit cannot carry black.
A chocolate rabbit will always be bb. A recessive gene cannot carry a dominant gene.
For an example if the Dam is BB - a black rabbit and the Sire is bb the offspring would all be black rabbits carrying chocolate which would look like this Bb.
However, if the sire; black rabbit carries chocolate as a recessive Bb and the dam is chocolate bb then statistically half the kits in the litter would be chocolate and half black.
Colours that are in the (B) Black set include black, sooty fawn, blue and black chinchilla.
Colours that are in the chocolate set include chocolate, lilac, choc tort, choc chinchilla and lynx.
As there are only two genes in this set there are only three possible combinations BB. Bb and bb
The (B) black gene being the most dominant and (b) chocolate the recessive.
Therefore, a black rabbit can carry chocolate (the b gene) which would appear like this Bb, but a chocolate rabbit cannot carry black.
A chocolate rabbit will always be bb. A recessive gene cannot carry a dominant gene.
For an example if the Dam is BB - a black rabbit and the Sire is bb the offspring would all be black rabbits carrying chocolate which would look like this Bb.
However, if the sire; black rabbit carries chocolate as a recessive Bb and the dam is chocolate bb then statistically half the kits in the litter would be chocolate and half black.
The C- Colour saturation gene
The C series gene is the most complex and the one I struggled with most to understand.
The colour gene determines where and how much colour is expressed rather than which colour.
Not only is there dominant and recessive genes there are also genes that have co - dominance and incomplete dominance and also a gene that is affected by temperature.
There are five different genes in this set listed in order of dominance; C - full colour gene, cchd - dark chinchilla gene, cchl - light chinchilla (sable gene) ch - the Himalayan gene and c - the albino gene.
This set of genes will determine how full the colour of the coat is.
The C gene allows full colour pigment, However on the other end of the spectrum the c gene, most recessive of the gene set will demonstrate a complete loss of colour, or an albino, (red eyed white)
Note; this gene is not responsible for BEW, blue eyed white this is a different gene (The Vienna gene)
The cchd, dark chinchilla gene and the cchl, sable gene share co-dominace.
They can only be expressed when paired with any gene other than the C - full colour gene.
The chinchilla gene cchd will allow production of some but not all colour in the rabbit. The yellow pigment in the coat is turned to white. It can also affect the eye colour turning the eye colour blue.
Some colours that carry the cchd gene include, chinchilla, squirrel, choc chinchilla and sallander.
The cchl gene, light chinchilla (sable) is slightly different than other genes in that is has incomplete dominance. When you have a rabbit that inherits two cchl genes, cchl cchl it results in not a sable coloured rabbit but a seal coloured rabbit, (dark sepia colour)
The cchl gene removes yellow pigment from the hair shaft but also removes some of the darker pigments too giving the rabbit a shaded look. However unlike the cchd gene this gene will leave the eye colour dark.
Some colours that carry cchl gene, are sable, seal point and smoke pearl.
The ch gene is known as the Himalayan gene and as I mentioned
earlier this is the gene that is affected by temperature.
Rabbits displaying this gene are pointed white, the rabbit will be coloured white except on the muzzle, nose, ears and feet.
This gene is sensitive to temperature as the rabbits that carry this gene will actually show their colour better in the colder months.
The most recessive of the genes is the c gene, the albino gene. The c gene, known as an epistatic gene will completely mask the other genes in the genotype of the rabbit when paired with another c gene, (cc). Making it visually impossible to know what other genes are underneath “the white coat”
(The best way to determine what other genes your REW carries is to test mate it with a coloured rabbit.)
The colour gene determines where and how much colour is expressed rather than which colour.
Not only is there dominant and recessive genes there are also genes that have co - dominance and incomplete dominance and also a gene that is affected by temperature.
There are five different genes in this set listed in order of dominance; C - full colour gene, cchd - dark chinchilla gene, cchl - light chinchilla (sable gene) ch - the Himalayan gene and c - the albino gene.
This set of genes will determine how full the colour of the coat is.
The C gene allows full colour pigment, However on the other end of the spectrum the c gene, most recessive of the gene set will demonstrate a complete loss of colour, or an albino, (red eyed white)
Note; this gene is not responsible for BEW, blue eyed white this is a different gene (The Vienna gene)
The cchd, dark chinchilla gene and the cchl, sable gene share co-dominace.
They can only be expressed when paired with any gene other than the C - full colour gene.
The chinchilla gene cchd will allow production of some but not all colour in the rabbit. The yellow pigment in the coat is turned to white. It can also affect the eye colour turning the eye colour blue.
Some colours that carry the cchd gene include, chinchilla, squirrel, choc chinchilla and sallander.
The cchl gene, light chinchilla (sable) is slightly different than other genes in that is has incomplete dominance. When you have a rabbit that inherits two cchl genes, cchl cchl it results in not a sable coloured rabbit but a seal coloured rabbit, (dark sepia colour)
The cchl gene removes yellow pigment from the hair shaft but also removes some of the darker pigments too giving the rabbit a shaded look. However unlike the cchd gene this gene will leave the eye colour dark.
Some colours that carry cchl gene, are sable, seal point and smoke pearl.
The ch gene is known as the Himalayan gene and as I mentioned
earlier this is the gene that is affected by temperature.
Rabbits displaying this gene are pointed white, the rabbit will be coloured white except on the muzzle, nose, ears and feet.
This gene is sensitive to temperature as the rabbits that carry this gene will actually show their colour better in the colder months.
The most recessive of the genes is the c gene, the albino gene. The c gene, known as an epistatic gene will completely mask the other genes in the genotype of the rabbit when paired with another c gene, (cc). Making it visually impossible to know what other genes are underneath “the white coat”
(The best way to determine what other genes your REW carries is to test mate it with a coloured rabbit.)
The d - dilution gene
This gene is fortunately quite straight forward.
There are only two genes in this set Dense colour - D and dilute colour -d
Dense being the dominant gene and dilute being the recessive.
All Dense colours have a corresponding dilute colour.
For example, blue is the dilute of black,
Here are some more
Lilac dilute of chocolate,
Opal dilute of agouti
Cream/fawn dilute of orange
Squirrel dilute of black chin
Lilac chinchilla dilute of choc chinchilla
Lynx (lilac agouti) dilute of chocolate agouti
Beige/Isabella dilute of sooty fawn
Lilac tort dilute of chocolate tort
For a rabbit to be a dilute colour it must inherit a dilute gene from each parent. Genetically it would appear like this dd.
Remember dense colour is more dominant and can only produce a dilute colour if it carries the dilute gene (Dd) and is paired with another rabbit that is either a dilute colour (dd) or a dense
colour carrying dilute (Dd)
A dense coloured rabbit cannot produce a dilute colour if it doesn’t carry the dilution gene even when mated with a dilute colour rabbit. Each rabbit MUST carry dilute to produce dilute coloured offspring.
The E - extension gene
There are four genes in this set, E, full colour extension, Es, extension of dark colour, e, extension of light colour and ej, Japanese harlequin pattern.
The Es gene produces steel coloured rabbits and is actually dominant over the full colour extension gene (E) Steeling will only ever appear in full extension coloured rabbits it cannot appear in non extension colours (ee)
This gene determines whether the colour will be extended all the way to the end of the hair shaft or if it stops at any point and another colour finishes.
When a rabbit has full extension it appears to look the same colour all over such as the appearance of a black or a blue coloured rabbit.
However, rabbits that exhibit non extension such as a sooty fawn take on a shaded look as the shorter hairs around the stomach, feet and muzzle aren’t long enough to show the colour change within the hair shaft.
Care should be taken not to confuse the non extension gene with the C series gene which can also result in shaded rabbits but for a completely different reason.
The gene that is located between the full extension gene and the non -extension gene is called the japanese harlequin gene (ej). This gene is responsible for harlequins, Tri - colours (harlequin butterfly's) and magpies (chinchillated harlequin).
The full extension gene (E) and the steel gene (Es) can both carry the harlequin gene (ej) But non-extension (ee) cannot.
If the japanese harlequin gene is carried by the steel gene (Es) it can visually mask the appearance of both genes.
The japanese harlequin gene (ej) works best when it is paired with the agouti gene (A) for the best coloured harlequin. When paired with self (aa) it can create a sooty harlequin marked rabbit and is not classed as a "true harlequin" as the sooty shading mixes unfavourably with the harlequin brindling.
The Es gene produces steel coloured rabbits and is actually dominant over the full colour extension gene (E) Steeling will only ever appear in full extension coloured rabbits it cannot appear in non extension colours (ee)
This gene determines whether the colour will be extended all the way to the end of the hair shaft or if it stops at any point and another colour finishes.
When a rabbit has full extension it appears to look the same colour all over such as the appearance of a black or a blue coloured rabbit.
However, rabbits that exhibit non extension such as a sooty fawn take on a shaded look as the shorter hairs around the stomach, feet and muzzle aren’t long enough to show the colour change within the hair shaft.
Care should be taken not to confuse the non extension gene with the C series gene which can also result in shaded rabbits but for a completely different reason.
The gene that is located between the full extension gene and the non -extension gene is called the japanese harlequin gene (ej). This gene is responsible for harlequins, Tri - colours (harlequin butterfly's) and magpies (chinchillated harlequin).
The full extension gene (E) and the steel gene (Es) can both carry the harlequin gene (ej) But non-extension (ee) cannot.
If the japanese harlequin gene is carried by the steel gene (Es) it can visually mask the appearance of both genes.
The japanese harlequin gene (ej) works best when it is paired with the agouti gene (A) for the best coloured harlequin. When paired with self (aa) it can create a sooty harlequin marked rabbit and is not classed as a "true harlequin" as the sooty shading mixes unfavourably with the harlequin brindling.
En -The pattern gene
The En broken gene is responsible for broken coloured rabbits/butterfly’s
There are two genes in this set En -spotting and en-solid colour. En being dominant over en.
There are few different combinations in how this gene can work;
Enen causes normal spotting
enen -Solid colour
EnEn broken - broken aka charlie
If you breed a solid coloured rabbit enen to a broken Enen the probability of broken vs. solids in the litter would be 50/50
However, if you breed a broken Enen to a broken Enen you run the risk of Charlie’s appearing in the litter.
A Charlie, genotype EnEn (broken -broken) is a rabbit with not enough spotting on it, A nearly white rabbit with only a small amount of markings on it and is not a showable colour .
However a charlie is really good for breeding broken/butterflys. if you breed a Charlie (EnEn)to a solid enen, It will guarantee you a full litter of broken/butterfly’s (Enen).
There are two genes in this set En -spotting and en-solid colour. En being dominant over en.
There are few different combinations in how this gene can work;
Enen causes normal spotting
enen -Solid colour
EnEn broken - broken aka charlie
If you breed a solid coloured rabbit enen to a broken Enen the probability of broken vs. solids in the litter would be 50/50
However, if you breed a broken Enen to a broken Enen you run the risk of Charlie’s appearing in the litter.
A Charlie, genotype EnEn (broken -broken) is a rabbit with not enough spotting on it, A nearly white rabbit with only a small amount of markings on it and is not a showable colour .
However a charlie is really good for breeding broken/butterflys. if you breed a Charlie (EnEn)to a solid enen, It will guarantee you a full litter of broken/butterfly’s (Enen).
The Vienna gene (BEW)
The Vienna gene is the gene responsible for blue eyed white rabbits and is a colour I have worked on a lot in the past.
Blue eyed whites are still fairly rare and the ones that are around don’t tend to be a very good type. My project is to better the type of my BEW rabbits using BEW carriers of a good type. It can be a lengthy process.
Let me explain how this gene works,
The Vienna gene is actually present in all rabbits
A rabbit that is not a blue eyed white or a vienna carrier, genetically appears like this VV, (upper case V ) it has two dominant Vienna genes.
The vienna gene will only visually appear when the recessive v (lower case) gene is present. When two v - recessive Vienna genes are paired together this will result in a blue eyed white rabbit.
When only one recessive Vienna gene is present (Vv) the rabbit will be a Vienna carrier (BEW carrier)
Vienna carriers (Vv) appear with white spots on their fur where there wouldn’t normally be any, a common place is on the top of their head, foot, (looking like a sock) and nose. I call these kits Vienna marked. (vm)
However, Vienna carriers do not always show white marks on their fur.
For example, If a BEW is bred to a solid coloured rabbit that is VV (does not carry BEW) it will result in a litter of (Vv) 100% vienna carriers.
Although none of the offspring will actually be BEW they will all be carriers, some might be vienna marked (vm) white marks visually apparent and others may be solid coloured and unmarked, However these kits will still carry the vienna gene and are known as (vc) or (Vv) vienna carriers they will definitely carry BEW even though white marks are not visually present.
These carriers are useful for breeding BEW’s as the carriers often are of better type than the actual bews.
The statistic probability of BEWS in the litter from a BEW vv to a BEW carrier Vv is 50/50
If a BEW/vienna carrier (Vv) is bred to another BEW/vienna carrier (Vv) statistically, it should result in 25% chance of BEW babies (vv). The other 25% will be normal/solid colour (VV) not carrying BEW at all) and the other 50% will be carriers (Vv)
If a BEW is bred to a BEW it will statistically result in a 100% full litter of BEWs.*
* (The exception to the rule is when both rabbits also carry the albino/REW gene (cc) or the himi gene (ch )
The Vienna gene, like the REW gene is an epistatic gene, meaning it masks the colour pigments of all other genes resulting in a blue eyed white rabbit.
Care must be taken not to mix Bew’s with your other coloured rabbits (not intended to be carriers) as it can result in undesirable white spots and white toenails in your coloured rabbits for generations to come.
It is also important not to use, chocolate or cchl (light chinchilla) gene in your BEW breeding project as this can give a ruby cast to the blue eye.
Blue eyed whites are still fairly rare and the ones that are around don’t tend to be a very good type. My project is to better the type of my BEW rabbits using BEW carriers of a good type. It can be a lengthy process.
Let me explain how this gene works,
The Vienna gene is actually present in all rabbits
A rabbit that is not a blue eyed white or a vienna carrier, genetically appears like this VV, (upper case V ) it has two dominant Vienna genes.
The vienna gene will only visually appear when the recessive v (lower case) gene is present. When two v - recessive Vienna genes are paired together this will result in a blue eyed white rabbit.
When only one recessive Vienna gene is present (Vv) the rabbit will be a Vienna carrier (BEW carrier)
Vienna carriers (Vv) appear with white spots on their fur where there wouldn’t normally be any, a common place is on the top of their head, foot, (looking like a sock) and nose. I call these kits Vienna marked. (vm)
However, Vienna carriers do not always show white marks on their fur.
For example, If a BEW is bred to a solid coloured rabbit that is VV (does not carry BEW) it will result in a litter of (Vv) 100% vienna carriers.
Although none of the offspring will actually be BEW they will all be carriers, some might be vienna marked (vm) white marks visually apparent and others may be solid coloured and unmarked, However these kits will still carry the vienna gene and are known as (vc) or (Vv) vienna carriers they will definitely carry BEW even though white marks are not visually present.
These carriers are useful for breeding BEW’s as the carriers often are of better type than the actual bews.
The statistic probability of BEWS in the litter from a BEW vv to a BEW carrier Vv is 50/50
If a BEW/vienna carrier (Vv) is bred to another BEW/vienna carrier (Vv) statistically, it should result in 25% chance of BEW babies (vv). The other 25% will be normal/solid colour (VV) not carrying BEW at all) and the other 50% will be carriers (Vv)
If a BEW is bred to a BEW it will statistically result in a 100% full litter of BEWs.*
* (The exception to the rule is when both rabbits also carry the albino/REW gene (cc) or the himi gene (ch )
The Vienna gene, like the REW gene is an epistatic gene, meaning it masks the colour pigments of all other genes resulting in a blue eyed white rabbit.
Care must be taken not to mix Bew’s with your other coloured rabbits (not intended to be carriers) as it can result in undesirable white spots and white toenails in your coloured rabbits for generations to come.
It is also important not to use, chocolate or cchl (light chinchilla) gene in your BEW breeding project as this can give a ruby cast to the blue eye.
