An introduction to English Lop color genetics

by Lily Patch Farm. Please do not reproduce this article in anyway without linking back to the original.

One of the most fascinating aspects of breeding rabbits is the ability to manipulate color and patterns. Conversely, one of the most frustrating aspects of breeding rabbits is trying to understand the science behind those colors and patterns!

This article is geared towards English lops, but most of it is applicable to all rabbits. While I am not claiming to be an expert in genetics, I have been a careful student of color genetics in several different species since I was a child. In college, my goal was animal husbandry and medicine with a strong focus in genetics. I came into rabbits with a background in genetics, which made things a lot easier for me to understand. I realize that not everyone is so lucky, so if this article helps one person a little bit I will feel all the better for writing it.


The number one thing to remember about genetics is the following.

Genetic laws are absolute and finite. They MUST be followed. There are no magic words, no wand, no amount of sacrifices to the God of Color that will allow a deviation from a Genetic Law. It is science and math, math and science. Why is it important to understand the genetic code behind your rabbit's color? Because it allows you to properly identify and label your kits, select breedings to produce showable colors, and successfully test breed to determine hidden genes your rabbits may carry. So, let's start at the beginning.


First, a vocabulary lesson.

Dominant: A dominant gene is a gene that ALWAYS expresses (shows) on a rabbit when it is present. It is absolutely, 100% impossible for a rabbit to "carry" a dominant gene, no matter what is in its pedigree. Two rabbits expressing recessive genes will always, always produce recessive rabbits. A dominant gene can be "masked" by a trait on a different allele, but it will always be expressed. An example of a dominant gene is agouti. Agouti is carried on the A (for agouti) locus and is written with a capital "A" to show dominance. Non-agouti is written with a lower case "a" to show that it is recessive to agouti. A chestnut is an example of an agouti rabbit. A black rabbit is an example of a non-agouti rabbit. If you were to breed two black rabbits 10,000 times, you would never produce a chestnut rabbit, because a rabbit expressing recessive traits cannot produce a rabbit expressing dominant traits.

Recessive: A recessive gene is a gene that does not express unless paired with another copy of itself, or with an allele that is recessive to it. It will always be hidden if paired with a dominant allele. Dilute (often called "blue") is an example of a recessive gene. Dilute is carried on the "D" locus (D for Dilute) and determines the saturation of the rabbits coloring. A black rabbit that shows dilute is a blue. A chocolate rabbit that shows dilute is a lilac. All dilute rabbits are homozygous for dilute as it is a recessive gene. Remember: you absolutely cannot breed two rabbits with homozygous recessive traits and get offspring with the dominant version of those traits. If you breed two blues 10,000 you will never produce a black rabbit.

Genotype: a genotype is the "code" behind an animal's color. It describes what the animal actually is, genetically speaking. It differs from phenotype, which describes the animal's PHYSICAL appearance. For instance if I were to say that I owned a broken chestnut buck I would be describing the animals phenotype. If I were to write that my buck was A_B_C_D_E_EN I would be describing the animal's genotype. Or, if you prefer, let's consider a cookie. If you tell someone you have a plate of chocolate chip cookies, it is like you are describing the phenotype of the food. What type of food is it? Chocolate chip cookies! But, if you were to say, well we have here flour, butter, milk, eggs, chocolate chips and sugar… it would be like describing the genotype. It's the "recipe" that makes up the final product! In ARBA, animals are shown, pedigreed and registered based upon their phenotype. In English Lops, this often means that animals are judged on the color they appear to be, rather than the color they actually are. A perfect example of this would be with a self-chinchilla. The term self-chinchilla refers to a rabbit that expresses chinchilla, but did not receive a copy of the agouti gene, so has no banding. This rabbit visually appears seal, but is genetically not seal. However, because ARBA shows are based on phenotype, the rabbit would be pedigreed, registered and shown as a seal. Another example, and one that frequently occurs in English Lops, is the confusion between "cream" and "lynx". Genetically speaking, the two are very different. Cream is black derived, and lynx is chocolate derived. However a smutty cream looks very similar to a lynx, and because ARBA registers based on phenotype, there are many smutty creams out there being advertised as lynx. This creates a problem for someone who is looking to add chocolate to their lines and purchases a "lynx" only to discover it is actually a smutty cream.

Locus: the chromosomal position of a gene as determined by its linear order relative to the other genes on that chromosome. You will often hear a breeder refer to an "a" locus, or a "b" locus. Rabbits have 6 main loci that determine color. A, B, C, D, E, and EN. Each of these loci attracts two alleles, or variations of genes from the source of genetic code (the parents off the offspring). You get ONE allele from each parent. It is a 50/50 random chance which allele an offspring will get from their parent. The two alleles together form a GENE. So a genotype is written with two spaces: AABBCCDDEEENEN (You may also notice someone use a "_" in place of a letter. That is a placeholder to indicate that the writer does not know the second or recessive gene "hidden" behind the dominant gene.) for instance, to represent each allele on each individual locus. The plural of "locus" is "loci".

In the above graph, we see the "A" locus (which determines whether or not a rabbit will be agouti). As you can see, mom has two alleles (aa) indicating she is not agouti, and dad has two alleles (Aa) indicating he IS agouti. The offspring will randomly (50/50 chance) receive one allele from each parent. In this case, the offspring received "a" or non-agouti from mom, and "A", or agouti from dad. Since agouti (A) is dominant over self (a), the baby will be agouti, like his father.

Homozygous: the term homozygous refers to an animal that has two identical copies of alleles on one locus. For instance, a blue rabbit is homozygous for dilute on the "D" locus. ("dd") Looking back up at our early graph, mom rabbit is homozygous for non-agouti on the A locus, because she has two of the SAME alleles on her A locus. Remember, the prefix "homo" means "same".

Heterozygous: the term heterozygous refers to an animal that has two different copies of alleles on one locus. For instance, an agouti rabbit may be AA (homozygous) on the A locus, or Aa (heterozygous) on the agouti locus. Again, looking back up at the graph above, we see that dad rabbit is heterozygous for agouti on the A locus, because he has two DIFFERENT alleles, one for agouti and one for non-agouti. In slang genetics, a rabbit that is heterozygous for a recessive gene is said to "carry" it. That means that they can produce rabbits expressing that gene, but that they do not themselves show it. Remember, the prefix "hetero" means "different".

Co-dominant/ stacked trait: The proper term for a gene that expresses differently in heterozygous and homozygous form is a co-dominate gene, but in genetic slang it's known as a stacked trait. Again, this is a trait that changes the phenotype of a rabbit when expressed in its dominant form homozygously. Let us look at sable as an example. Sable is carried on the "C" locus as c(chl). When a rabbit is heterozygous dominant sable [ c(chl)c ] they only have one copy of the sable gene. The other allele, in this case, is REW, which is recessive to sable and allows the sable to express. This produces a chocolate-like rich brown known as sable. A rabbit that is homozygous dominant sable [ c(chl)c(chl) ] has two copies of the sable gene. These two alleles "stack" ontop of each other and produce a different color, a very dark brown/almost black color known as "seal". Another example of a stacked trait would be the broken gene. One copy of the broken gene gives you a normal broken rabbit, but two copies of the broken gene "stacks" on top of each other and gives you a "Charlie" or a very lightly broken rabbit.

Punnett Square: the Punnett square is a quick and easy way to visualize the possibilities of an outcome of a single genetic trait. It is incredibly helpful to help determine the percentage of offspring you will produce that express any given trait. For instance, if you breed a black rabbit who you know carries dilute (let's say one of his parents was dilute, so he has to have one copy of dilute) and a blue rabbit that is homozygous dilute, the Punnett square for that pairing would look like this:

This is a punnet square illustrating the hereditary rate of the dilute gene. 

As you can see, inside the squares we get all the possible outcomes for that trait. In this case, there is a 50% chance to produce rabbits that are Dd (or non-dilute) and a 50% chance to produce rabbits that are dd (or dilute.) This does not mean that if you produce 6 kits, 3 kits will be dilute. What it means is that EACH KIT has a 50% chance of being dilute. It averages out. However, if you flip a coin 10 times in a row, it is possible to get heads 10 times. Likewise, it is possible to breed once and achieve a litter of all Dd and no dd.


(please understand that the above image is a simplified version and is not meant to actually be a representation of a chromosome!) The above image shows six loci with two alleles on each locus. For the purpose of this article, we will not be discussing Vienna, as it does not pertain to English Lops. I will be writing a separate article dealing with breeding in Vienna, as well as tan points, into English Lops at a later date.

The genetic code, or genotype, for this rabbit would be written AaBBCcddEEEnen. Phenotypically speaking, this rabbit would be a broken opal rabbit.

We are going to break down the genetic code into individual loci, starting with the "A" locus.

A Locus

A: Dominant agouti. Agouti is the most dominant gene possible on the A locus. Agouti creates banding in each individual hair shaft, white eye circles, and a white belly. Dominant "A" can be expressed Aa, Aat, or AA. Examples of rabbits that are dominant "A" on the A locus are: Chestnut, opal, orange, cream, lynx, and chinchilla. When you blow into the coat of these rabbits, you should see a clear definitive "ring" on the hair shafts.

at: Tan points. This gene creates the eye circles, white belly and white inner ears and under-tail of an agouti rabbit, but does NOT create the banding on each individual hair shaft. This is a partially dominant gene. It is dominant to "a", but NOT dominant to "A". Examples of rabbits that are "at" on the A locus are otter and silver martin rabbits. Rabbits that are dominant "at" on the "A" locus are expressed either atat or ata.

a: Self/non-agouti. This gene is the most recessive gene, and indicates a rabbit that does not have any banding, or eye circles/white belly/white inner ears etc. This is a self, non-agouti rabbit, like a purely black rabbit. All self rabbits are homozygous on the "A" locus. They are always expressed as aa, because they cannot hide any other gene.

B locus

The "B" locus controls the base color of a rabbit. All rabbits are either BLACK based, or CHOCOLATE based. Believe it or not, there are only TWO colors in rabbits. Black and chocolate. Black based rabbits have eumelanin, which is black pigment. All black based colors are the results of individual alleles altering the eumelanin. Chocolate based rabbits have pheomelanin, which is yellow/brown/red pigment. All chocolate based colors we see are the results of additional alleles altering the appearance of the pheomelanin.

B: dominant black. Most English lops are BB. In fact, the idea that chocolate even exists at all in English Lops is currently a heated debate among breeders. We won't take sides here, so we will say that a dominant black rabbit can be either heterozygous black or homozygous black, expressed as Bb or BB.

b: recessive chocolate. This gene is responsible for all chocolate based varieties including chocolate, lilac, chocolate chestnut, and lynx. All chocolate rabbits would be bb, or homozygous recessive, as once again, you must have two copies of a recessive gene for it to express. Chocolate is very uncommon in English Lops, and even (as previously mentioned) believed by some to not exist in purebred English Lops. There are a lot of rabbits that are labeled as chocolate that are actually sables, or seals, or light black torts, etc. If you believe that you have a chocolate, I highly suggest test breeding to a known chocolate of a different breed. If you get chocolates in that litter, then you know for sure your English Lop is chocolate. 

C Locus 

The "C" locus further impacts the color of the rabbit. This is probably the most difficult of all of the loci to understand, as there are five possible alleles and one of those is a stacking allele. Ok, let's dive in!

C- Dominant Full color. This is the most common and most dominant of the possible alleles. Examples of rabbits that are dominant full color are blacks, blues, blue torts, black torts, chestnuts, opals, oranges, creams, chocolates, and lynx. Dominant full color rabbits can be written as CC, Cc, Cc(chl), Cc(ch) or Cc(chd).

c(chl)- Co-Dominant Sable/Shaded- this stacked trait is responsible for both sable and seal. One copy removes all of the yellow from the hair shafts, creating a rich sepia toned rabbit. It also is a temperature sensitive gene, restricting the darkest colors to the areas of the rabbit most likely to get cold (ears, feet, tail, underbelly and face) while the areas that generally stay warmest (back and chest) stay lighter. This creates the shading affect. However, if you have a rabbit that is homozygous sable, the two alleles "stack" on top of each other, creating a much darker sepia tone, an almost black rabbit, with very little shading evident. This color is known as "seal".

c(ch)- Himalayan- This gene is responsible for pointed whites, such as the Himalayan rabbit. It restricts color to the feet, ears, tail, and muzzle of a rabbit and leaves the remainder of a rabbit pure white. Unlike most other genes, this one is also partially temperature controlled. The colder it is, the darker the points will be. (This is so that the rabbit will absorb more heat on the extremities of the body) Conversely, if it is TOO cold, then you will achieve a lot of smut (or excess color) on the body of the rabbit. Luckily, pointed white is not a showable color in English Lops and we do not have to worry about this!

c(chd)-chinchilla. Chinchilla removes yellow from the hair shafts and replaces it with white. Paired with agouti on the A locus, you get a traditionally colored chinchilla rabbit. When not paired with chinchilla, you get a rabbit that has the yellow removed from its hair shaft but no bands- this lightens the overall coat color of the rabbit and produces a rabbit that LOOKS like a seal rabbit and is referred to as a self-chinchilla.

c- REW. Otherwise known as Ruby(or red) Eyed White. This is the most recessive of the C locus alleles. Any rabbit can hide REW, but REWs cannot hide any other allele on the C locus. All REWs are cc. Remember that earlier I said that there is absolutely no way a rabbit could hide a dominant gene? This is still true. REW works like a white blanket, covering your rabbit and hiding its true color underneath…however, your rabbit is still expressing those dominant genes. It is just covered by the REW blanket. Your rabbit could be black, blue, chestnut, opal, a tort, etc… but will appear white.

D locus

The "D" locus controls the saturation of color on the rabbit's coat. It is controlled by the MLPH (Melanophilin) gene. Mutations of this gene cause color to clump along the hair shaft rather than evenly distribute. This affects how light reflects off of the hair shaft, resulting in a lighter looking, less color saturated coat.

D- Dominant non-dilute. Rabbits that are "D" have full saturation of their coats, resulting in a deep, dark color. For black based rabbits that are D, they show black fur. A black based rabbit that is dd shows blue fur.

d- Recessive dilute. Rabbits that are "dd" have incomplete saturation of color on their coats, resulting in a subdued, lighter hue. For a black rabbit this means blue. For a chocolate, this means lilac. Here is a list of SOME colors matched with their dilute counterparts.

Non Dilute

REMEMBER! You cannot breed two recessives and get a dominant. That means that no matter what, you will never be able to breed two dilute rabbits and get a non-dilute rabbit.

E locus

The "E" locus is the Extension locus. This locus controls how far the color extends on the individual hair shafts. There are three possible alleles on the "E" locus.

E: Dominant Full Extension. A rabbit that is dominant Full Extension will show color from the top of the hair shaft all the way to the skin. Most rabbits are dominant full extension. Examples of full extension rabbits are blues, blacks, chestnuts, chocolates, lilacs, chinchillas, sables, opals etc. Dominant full extension rabbits can be written as Ee, Eej, EEs or EE depending on what they carry for the second allele.

ej: Partially dominant Japanese. This is a fairly tricky little allele that is responsible for the harlequin pattern in rabbits. It is co-dominant, and will only express if it is homozygous on the E locus or is paired with its recessive counterpart "e" or non-extension. A solid rabbit that is dominant for Ej is a harlequin (otherwise known as a Japanese rabbit) a broken rabbit that is dominant for Ej is known as a tri color. The broken gene also breaks the striping of the harlequin pattern into smaller spots. A dominant Japanese rabbit will express as ejej or eje. The best harlequins/tri colors are ejej, as eje can result in some light torting or mild non-extension showing which is a disqualification.

e: recessive non extension. The gene for non-extension restricts the color on each individual hair shaft and does not allow it to extend to the end of the shaft, but rather allows the lighter core color to extend. This will produce a shaded look on many rabbits, and is responsible for the torting on rabbits. The shading is not true shading, but is actually an illusion. The full color only extends partially on the hair shaft, so the rabbit will appear darker in the face, ears, sides, stomach and paws since those areas have shorter hairs. On the back however, you will see less color because the individual hairs are longer, allowing the lighter core color to be the primary color you see. If you were to shave a dominant non extension rabbit for some reason, they would be the same color all over at the skin. The non-extension gene produces some drastic changes to a rabbit's phenotype depending on the color it is acting upon. Here are some examples.


ES-Partially dominant extension steel- This is a very tricky allele, and one that I actively work not to have in my barn. It is an incomplete dominant allele, but also a stacking trait, and for reasons that I will make clear can hide and muck up your other colors. If you are going to work with steel, I recommend having a separate line that you know could be steel, and not breeding it into your main herd as it can cause you to lose track of your other rabbit's genotypes without lots of test breedings.

So, steel is dominant to non-extension (e) and Japanese (ej), but recessive to full extension (E). Steel alters the rings on agouti rabbits by moving the light band to the tip of the hair, rather than the middle of the hair, resulting in a "sprinkling" of color on top of the fur but no rings. It also alters eye rings and the white belly on agouti rabbits. Depending on what color the rings would be (on a normal chestnut they would be gold, on a chinchilla they would be silver for instance) you will get gold tipped, or silver tipped steels. Although steel is dominant, it cannot express without Agouti, since without agouti there are no bands of color to alter. A self-steel will appear a normal self rabbit, but will throw steels, which can be incredibly confusing if you are not aware that your rabbit is genetically steel. Additionally, the steel alleles can stack. A rabbit that is homozygous for steel will have the bands completely removed from the fur, rather than just moved, resulting in a rabbit that is deceptively dark, almost appearing self, although it is actually both agouti and steel. In conclusion, steel is not generally considered a gene for the faint hearted!

EN Locus

The last Locus we will discuss is the "EN" locus. This locus determines whether or not a rabbit carries English Spotting, or "broken" patterning. There are only two possible alleles:

En: English Spotting, dominant stacking gene. A rabbit with ONE dominant English spotting allele is a broken rabbit. A rabbit with two English spotting alleles (homozygous dominant English spotting, or EnEn) is a Charlie rabbit. The two broken genes "stack" ontop of each other and produce a greater affect on the rabbit's pattern than a rabbit who is heterozygous for En.

en: recessive solid. This gene is recessive and determines that the rabbit will be solid. All solid rabbits are enen, or homozygous recessive. Repeat after me! It is impossible to breed two homozygous recessive rabbits and produce a dominant animal. That means no matter what, no matter how many breedings, two solid rabbits will never produce a broken rabbit.

The broken gene is one gene I am asked about frequently. Lets draw a few Punnett squares to determine the outcome of some breedings!

Ok let's look at this breeding. On top, we see a broken (Enen). On the side, we see a solid rabbit (enen). When drawn out, we see that this type of breeding would give us a 50% chance of producing brokens, and a 50% chance of producing solids.

This breeding shows a broken (Enen) bred to a broken (Enen). As we see here, we get a diverse outcome in our kits! This breeding will give us a 25% chance of producing solids (enen), a 25% chance of charlies (EnEn) and a 50% chance of producing brokens (Enen).

This breeding shows two solid rabbits (enen). A solid rabbit is homozygous recessive on the en locus. They do not carry the broken gene. Breeding two solids will always, always result in 100% solid rabbits.

Here, we see a Charlie (EnEn) bred to a solid (enen). This is actually the very reason that most people will keep a nice Charlie, even if unshowable, if brokens are a goal in their breeding program. As you can see by our Punnett square, you get 100% brokens in this breeding.

The last breeding we will examine will be a Charlie (EnEn) to a broken (Enen) this is not generally a recommended breeding. You will produce 50% non-showable Charlies with this breeding, and 50% brokens.

Breeder cheat sheet!

Listed below are all of the acceptable (and a few unacceptable!) colors for English lops, and the possible genotypes that could go into making them. Remember that a (_) means there are multiple possible combinations that could follow but would still result in the same phenotype. A dominant gene will never be hidden by a (_) unless it is being masked by a REW.


  Chestnut is a very dominant, wild color in rabbits. Black chestnut is dominant on all loci- agouti, black, full color, non-dilute and full extension
  Opal is the dilute version of Chestnut and is therefore homozygous dilute on the D locus.
  This is the same as a black chestnut agouti, only chocolate based, so is homozygous recessive chocolate on the "b" locus
  This is a chestnut that is homozygous recessive on the "B" locus (so chocolate) and ALSO homozygous recessive on the "D" locus, so dilute.
  This is a black chestnut rabbit who is homozygous recessive for non-extension. The agouti eye bands/belly remain white, but the dark color on the individual hairs do not extend full length, resulting in an orange rabbit.
  This leads to some confusion in English lop breeders, especially coming from other breeds. In other breeds Fawn refers to the dilute of Orange. In English Lops we use fawn to refer to a rabbit that is genetically orange but has a dustier, paler orange than a bright red orange. This is due to rufus factor. Rufus is selectively  bred in, and determines how red a rabbit appears. Higher rufus animals are orange, lower rufus animals are fawn.
  This is a dilute orange, or an opal rabbit that is homozygous recessive for non-extension
  This is a chocolate based dilute orange. Or, a homozygous non extension lilac chestnut.
  This is a chestnut agouti rabbit that exhibits chinchilla on the C locus. Chinchilla removes the tan from the hair shaft, leaving silvery bands in it's place.
  This is a dilute chinchilla
  This is a chestnut agouti rabbit also exhibiting the Japanese gene (harlequin)
  This is a harlequin rabbit also exhibiting chinchilla. A blue magpie would be the same except dd on the D locus.
  This is a chinchilla rabbit also exhibiting non-extension. A rabbit that is dominant chinchilla and also homozygous recessive non-extension will result in a nearly pure white rabbit.
  This is the dilute version of a black frosted pearl
  A chestnut agouti exhibiting steel. The gold agouti rings are pushed to the tips of the hairs and the eye rings are eliminated. A self steel would be a rabbit that does not carry agouti but does exhibit the steel gene ( aaB_c(chd)_DDEse). A self steel will appear like a self with a few if any scattered white or gold hairs. 
  A chinchilla exhibiting steel. The silver agouti rings are pushed to the tips of the hairs and eye rings are eliminated.
  An opal rabbit exhibiting steel. The silver agouti rings are pushed to the tips of the hairs and eye rings are eliminated.
A blue chinchilla rabbit exhibiting steel. The silver agouti rings are pushed to the tips of the hairs and eye rings are eliminated. A self steel would be a rabbit that does not carry agouti but does exhibit the steel gene ( aaB_c(chd)_ddEse). A self steel will appear like a self with scattered white hairs. 
  Non agouti, black based full color, non dilute, full extension
  Non agouti, black based, full color, full dilute, full extension
  Non agouti, chocolate based, full color, non dilute, full extension
  Non agouti, chocolate based, full color, dilute, full extension
  This is a chinchilla rabbit that did not get a copy of the agouti gene. Without a copy of the agouti gene, there are no tan bands and eye circles/belly to turn white, so this rabbit just looks like a very dark chocolate or seal rabbit. In reality, it is called a self chinchilla.
  This is a black rabbit that is also homozygous for non extension, resulting in the classic torted rabbit.
  This is the dilute version of a black tort.
  This is a chocolate rabbit that is homozygous recessive for non-extension
  This is a dilute chocolate rabbit that is homozygous for non-extension
  Non agouti, black based, shaded (sable) rabbit with full extension and no dilution
  Non agouti, black based, homozygous incomplete dominant shaded (sable) with full extension and no dilution. The two sable alleles stack ontop of each other and create a dark near solid colored rabbit, known as a seal.
  The dilute version of a sable
  The dilute version of a seal
  A sable rabbit homozygous for non-extension, creating a faux version of a pointed white. It is not truly a pointed white however, just the non-extended version of a sable. You could accurately describe this color as a "sable tort"
  Known as blue points, dilute sable points and smoke pearl points depending on who you talk to, this is the dilute version of a sable point. It is currently a non- showable color.
  A pointed white is any color with a dominate c(ch) on the C locus, creating the base color only at the points
  A REW can be absolutely any color other than chinchilla, shaded or pointed white as the C locus is homozygous recessive. Think of REW as a blanket covering the true color of the rabbit. Underneath, the rabbit could be agouti, or self, broken or solid, dilute or non dilute, full extension or non extension, or Japanese or steel. It is just masked under the REW blanket! The only way you will be able to fill in the blanks on a REW is by test breeding and careful examination of the pedigree.
 Any Color- Broken
 Take any of these genotyopes and add Enen to them, and you have a broken rabbit. Add EnEn and you have a charlie rabbit.

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That's all for now folks! I will be adding a FAQ section, pictures of kits and adults of the same colors, and detailed pictures of ring patterns and how to tell the difference between certain colors at a later date. Also keep checking back for my article on selectively breeding new colors into your herd!