Breeding For Brokens and Charlie's

In this article we are talking about breeding New Zealand's (NZ) for specific patterns, not necessarily for color. In order to do that we need to know exactly what defines a solid, broken, or charlie pattern. According to the American Rabbit Breeders Association (ARBA) there are only three sanctioned solid colors of New Zealand Rabbits: red, white, and black (blue is not yet an approved color). Solids rabbits are generally considered 'self' colored rabbits, as they all carry the (aa) allele pairing. The one exception in NZ rabbits is the New Zealand Red (NZR). The NZR, while not only being the original color of the breed is actually an agouti, which means that it carries either the (AA or Aa) allele pairing. (For more information about genetics and allele pairing see my three articles on NZ color genetics). However, when it comes to breeding for patterns, the NZR is considered a solid.

According to ARBA there are only two sanctioned broken colors of New Zealand Rabbits: red & white, and black & white (blue & white is not yet an approved color). A quality broken pattern is one in which both ears colored, with color around the eyes, and on the nose. The body pattern may be spotted, with individual colored spots or patches over the back, sides, and hips: or a blanket pattern with color starting at or near the neck, and continuing over the back, sides, and hips in an evenly balanced pattern. Toenails may be white, colored, or any combination of the two.

Charlies are the red-headed step children of NZ rabbits when it comes to the ARBA as they are not recognized for show purposes. In appearance, a charlie looks like a broken 'lite' if you will (meaning it has a similar, but a lot smaller color pattern due to their different allele pairing (EnEn). While they are not shown much love by ARBA, for breeders however, charlies are an important part of their breeding and livestock sales as many people are looking for good quality charlies. Of the three patterns (solid, broken, and charlie) the charlie pattern is the least common.

Solids

A solid black or white New Zealand (NZ) rabbit should be the same color all over, however that is not exactly true for all of the other colors of the breed. For example, The New Zealand Red (NZR) has a red upper body coat, while the fur on the belly is a lighter shade of red or tan/cream color. For show purposes, the one thing that all NZ solids (except reds) have in common is that their coat should not be interspersed with any color of fur. When judging show rabbits even one small hair of a different color located between a toe can cause a rabbit to be disqualified.

Keep in mind that a 'solid' or 'self' colored rabbit may also be referred to as 'steel tipped' if it carries the (Es_) allele. In rabbits with this allele, the color of some of the hair on the fur will have silver to orange coloring on the tips of the hair shaft. Other than being 'steel tipped' If the rabbit in question has any pattern in which one color is interspersed with another (red and white, black and white, or blue and white) then it is classified as either a 'broken' or a 'charlie'.

Broken Pattern

A NZ rabbit with a broken pattern will be one of three color patterns (red & white, black & white, and blue & white). The primary colored portions of fur occur in a patched or blanketed pattern on the face, ears, and nose of the rabbit. Ideally, a rabbit with a broken pattern should have a balanced marking on its nose (full butterfly). The ears should be totally colored and the front feet should be white. The fur around the eyes is generally the base color of the rabbit with some white interspersed. Overall, the amount of colored fur or 'broken pattern' on the rabbit should be evenly distributed, however the actual amount of color may vary from 10 to 70 percent.

Charlie Pattern

A NZ rabbit with a charlie pattern will be one of three color patterns (red & white, black & white, and blue & white). Similar to brokens, a charlie has it's own specific type of pattern. A charlie may look like a broken, but there are specific patterns that are looked for in charlies that brokens do not have. A distinct marking that generally stands out on charlies is their abbreviated patch of color on their nose. It is quite a bit smaller that the full 'butterfly' mustache of a broken, hence the nickname “charlie” because this distinct nose marking is similar to the 1920's comedic actor Charlie Chaplin. Later, we will discuss how Charlies are genetically different from patterned rabbits, and they often look like sparsely patterned brokens, often having less than 10% color on a field of white fur. While some brokens may look like Charlies, Charlies are a distinctively different rabbit genetically. If the rabbit in question has a parent that is solid, then the rabbit cannot be a Charlie. In addition, if a rabbit that is suspected to be a Charlie and during breeding it produces even one solid offspring, it is not a Charlie, it is a broken. This will all be made clear when we examine the gene that is responsible for these patterns, the English spotting gene.

The English Spotting Gene:

The 'En' or English Spotting gene is the gene responsible for producing both broken and charlie patterns. As with color, breeding for a specific hair or fur pattern is simply a matter of genetics. Every complete gene is made of two allele's with each parent giving one allele to their offspring to make a complete pair. If you understand nothing else, then this is all you need to know, so I will repeat it, each parent gives one of their offspring one half of the allele paring that produces the rabbits specific color pattern or lack their of. Believe it our not there are only three possible combinations. The rabbit either has no pattern (enen) allele pairing, has a broken pattern (Enen) allele pairing, or has a charlie pattern (EnEn) allele pattern.

Normally allele pairings are written as two specific genes inside a set of parenthesis. For example the charile allele pair is denoted as (EnEn). To help make the concept of gene donation easier to understand, I will write these pairings with a comma between them to help those of you who are new to color and pattern genetics differentiate between the individual allele's. Keep in mind that each parent supplies one allele (or half) of the gene to make the allele pair of their offspring. Just remember that the correct way to write an allele pairing is (EnEn) not (En, En).

Broken Pattern (Enen) or (En, en)

Charlie Pattern (EnEn) or (En, En)

No Pattern or Spots (enen) or (en, en)

So let's look at some possible pattern combinations when we breed a:

Solid (en, en) to Solid (en, en) = 100% solids.

• Solid to solid will give you 100% solids, no ifs or buts here.

Solid (en, en) to Broken (En, en) = some brokens (En, en), but mostly solids (en, en).

• You will get the occasional broken here, but with three 'en' allele's and only one 'En' allele, the mathematical chance that you will get a broken in a liter is about 25%.

Broken (En, en) to Broken (En, en) = some brokens (En, en), some solids (en, en), some charlies (En, En).

• This combination has the potential for the most variety. With an even number of 'en' and 'En' allele's you will get will get a higher percentage of brokens (about 50%), but you will get some solids and charlies as well (about 25% each).

Charlie (En, En) to Broken (En, en) = some brokens (En, en), and some charlies (En, En).

• You will get the occasional broken here, but with three 'En' allele's and only one 'en' allele, you will get mostly charlie's (about 75%) while the mathematical chance that you will get a broken in a liter is about 25%. There is not possibility of getting a solid rabbit from this breeding.

Charlie (En, En) to Charlie (En, En) = 100% charlies.

• Charlie to charlie will give you 100% charlies, no ifs or buts here.

Keep in mind that these mathematical percentages will bear out over time with multiple breedings. It is possible that in one breeding of broken (En, en) to broken (En, en) that you get all brokens and no solids or charlie's, that's simply the way genetics work. So keep that concept in mind when you breed. The only two breeding combinations that will give you 100% known outcomes are solid-to-solid and charlie-to-charlie. The rest of the time it is up to nature. However, keeping good breeding records and knowing which pattern combinations have the potential (mathematical percentage) to produce certain color patterns will help you to be successful in your pursuit of breeding or brokens and charlies.

Conclusion

When it comes to genetics, breeding for a specific color pattern (solid, broken, or charlie) is quite a bit easier than trying to figure out the individual color genome of each rabbit. After all, you only need to know whether the buck and or doe is a solid, broken or charlie. The rest is basic probability (mathematics), and nature will take care of that for you. You may not get the exact outcome you want with every breeding, but eventually with careful breeding the math works itself out and over time you will see that certain breedings will give you a certain percentage of broken or charlie kits that you desire. As always, if you have found this article interesting or informational please share it with your friends. Don't forget to follow us on Facebook or on Google+ for the latest articles on our blog related to raising your own meat rabbits.

Additional Articles On Genetics On Our Blog:

New Zealand Rabbit Genetics Part 1: Dominant And Recessive Genes

New Zealand Rabbit Genetics Part 2: Coat Color, It's In The Genes.

New Zealand Rabbit Genetics Part 3: Putting It All Together.

New Zealand Rabbit Genetics: Putting It All Together

So how did I get started down this road to try and decipher the genetic makeup of the New Zealand (NZ) rabbit? The answer is pretty simple really. Like many people new to breeding rabbits, I thought that If I bred a New Zealand Red (NZR) with a New Zealand White (NZW) then surely I should see some red, white, and possibly some red and white (broken or charlie) offspring (kits) in my litters. What I found out was that always got chestnuts, and or dark colored steel tipped kits from these pairings with no whites, reds, or patterned (broken or charlie) offspring. My NZR to NZR pairings always resulted in beautiful red offspring with no variations in color or color patterns. While my NZW to NZW pairings almost always produce white kits, I had one female who continued to occasionally produce a black litter when she was bred with a white male from another breeder friend of mine which kind of baffled me. So I decided that after three years of raising and breeding rabbits it was time to dive into the subject of genetics and the NZ rabbit genome.

In the second article of this series 'Coat Color: It's In The Genes' we examined the entire NZ rabbit genome or genotype and at the end of the article I listed the basic genotype of each of the NZ rabbit color combinations. Just for convenience I am going to re-list those color gene sequences below for your reference.

Agouti (Chestnut): A_, B_, C_, D_, E_, enen, DuDu, SiSi, VV, W_

Black: aa, B_, C_, D_, E_, enen, DuDu, SiSi, VV, W_

Blue: aa, B_, C_, dd, E_, enen, DuDu, SiSi, VV, W_

Red: A_, B_, C_, D_, ee, enen, DuDu, SiSi, VV, ww +++

White: A_, B_, cc, D_, E_, enen, DuDu, SiSi, VV, W_

The Brokens:

Black: aa, B_, C_, D_, E_, Enen, DuDu, SiSi, VV, W_

Blue: aa, B_, C_, dd, E_, Enen, DuDu, SiSi, VV, W_

Red: A_, B_, C_, D_, ee, Enen, DuDu, SiSi, VV, ww +++

The Charlies:

Black: aa, B_, C_, D_, E_, EnEn, DuDu, SiSi, VV, W_

Blue: aa, B_, C_, dd, E_, EnEn, DuDu, SiSi, VV, W_

Red: A_, B_, C_, D_, ee, EnEn, DuDu, SiSi, VV, ww +++

As I mentioned in 'Coat Color: It's In The Genes' all NZR's share the (DuDu), (SiSi), and (VV) allele pairings so many breeders simply drop these when denoting the NZR genotype. For the rest of this article I will be doing the same, just know that if you want a complete 10 color genome listing add the proper allele pairings to the genome. So The basic genome of the breed would look as follows when abbreviated. NZ rabbit basic color genome: A_, B_, C_, D_, E_, en_, W_.

Putting It All Together

Without DNA testing, there is only one way you can try and fill in the blank spaces in your rabbit's genome. It's the method that breeders of livestock have used for thousands of years and that is simply breeding your rabbits and writing down your individual results. If you keep through consistent records you will eventually be able to fill in most of the blanks on your rabbits color genome based on your own out comes. The key here is consistency and good record keeping. If you are raising meat rabbits for just meat then you probably do not care what the rabbit's coat color looks like as all the meat tastes the same regardless of coat color. However, if you want to breed for a specific color or color pattern in order to increase not only your breeding stock, but potential sales of breeding stock, then it is good to have an idea of the genetic makeup of your rabbits. Eventually most breeders not only want to supply their family with meat to eat, but rabbit sales to supplement their income or at least pay their feed bills.

The New Zealand Agouti “Chestnut”

Basic Genome: A_, B_, C_, D_, E_, enen, W_

The New Zealand Agouti (NZR) is the original color of the breed. The upper coat is a reddish sorrel color, with the pigment running the length of the hair shaft. The coat on the belly color tends to be the same color with a slight lightening or cream color in the middle of the abdomen, the underside of the tail, the front or rear food pads and around the eyes. Their eyes are brown in color. The NZR carries the agouti (A_) gene and when breed with self (aa) colored NZ rabbits will possibly produce steel-tipped kits as well as a variety of different shades depending on other genetic modifiers.

The New Zealand Black

Basic Genome: aa, B_, C_, D_, E_, enen, W_

Broken Black Basic Genome: aa, B_, C_, D_, E_, Enen, W_

The New Zealand Black (NZB) has an upper coat with a uniform dark black throughout. The undercoat may be a uniform, black color or it may be a dark slate blue color with dark brown eyes. The NZB is a self (aa) colored rabbit and when bred with another with self (aa) colored NZ rabbit will possibly produce steel-tipped kits as well as a variety of different shades depending on other genetic modifiers.

The New Zealand Blue

Basic Genome: aa, B_, C_, dd, E_, enen, W_

Broken Blue Basic Genome: aa, B_, C_, dd, E_, Enen, W_

The New Zealand Black (NZBL) has an upper coat with a uniform dark black throughout. It is the dilute (dd) allele pairing that causes the black (B_) allele to become diluted from a black to blue coat. The undercoat may be a uniform, blue color or it may be a dark slate blue color with dark brown eyes. The NZBL is a self (aa) colored rabbit and when bred with another with self (aa) colored NZ rabbit will possibly produce steel-tipped kits as well as a variety of different shades depending on other genetic modifiers.

The New Zealand Red

Basic Genome: A_, B_, C_, D_, ee, enen, ww, rufus-modifier

Broken Red Basic Genome: A_, B_, C_, D_, ee, Enen, ww, rufus-modifier

The New Zealand Red (NZR) is the original color of the breed. The upper coat is a reddish sorrel color, with the pigment running the length of the hair shaft. The coat on the belly color tends to be the same color with a slight lightening or cream color in the middle of the abdomen, the underside of the tail, the front or rear food pads and a around the eyes. Their eyes are brown in color. The NZR carries the agouti (A_) gene and when breed with self (aa) colored NZ rabbits will possibly produce steel-tipped kits as well as a variety of different shades depending on other genetic modifiers.

The New Zealand White or 'Ruby Eyed White' (REW)

Basic Genome: A_, B_, cc, D_, E_, enen, W_

The New Zealand White (NZW) is probably the rabbit that most people think of when you mention the words “New Zealand Rabbit”. It is the most commercially produced as well as breed for show variety of the NZ rabbits. In fact, it is the gold standard for commercial rabbit meat production and laboratory testing as well as a great rabbit to breed at home for meat production. The NZW is technically and albino (lack of melanin), because the NZW is an albino, the other genes colors that would normally make up it's genetic code are suppressed. That does not mean that the other color gene's are not there, rather the albino gene (cc) blocks the color of all the pigments along the hair shaft and eyes, producing a white rabbit with pink/red eyes known as a 'ruby-eyed white (REW)'. It can still be a carrier for all the other genes, it is just that you may not see their expression until you breed a white rabbit with a rabbit of another color.

The Breeding Trials

So let's look at how you can begin to fill in some of the blank spaces on you NZ rabbits genome. I have listed the basic color genome for our NZR buck 'Long Eared Red' (LER) and the our NZW doe Luna which we have breed to several times. For whatever reason she is most responsive to this buck so I almost always breed her to him. LER's red coloring is right in the middle of the red color range so my best guess is that he has three rufus-modifiers denoted as (+++) at the end of his genome, the words 'rufus-modifier' have been replaced by this notation. As I mentioned earlier their pairings always produce either agouti's and or steel tipped kits. Looking at the various litters that these two rabbits have produced, I can now begin to apply some of my knowledge to start and flesh out their color genome's.

Our NZR buck 'LER's' Basic Genome: A_, B_, C_, D_, ee, enen, ww, +++

Our NZW doe “Luna's' Basic Genome: A _, B_, cc, D_, E_, enen,W_,

I have bred these two rabbits multiple times and I always get a combination of chestnut agouti's and black cinnamon tipped steel kits, the majority of them being steel tipped. So let's see if we can flesh out the color genome of these two rabbits gene by gene. It is important to remember that each parent gives one allele to it's offspring to complete the pair. Knowing this, we can look at their offspring to help us to fill in the blanks in their genetic color code.

Their last litter basic genome:

2 - Chestnut Agouti's Aa, B_, C_, D_, Ee, enen, Ww

5 – Black Cinnamon Tipped Steels aa, B_, C_, D_, Ese, enen, Ww

A-Series Genes: Agouti (A_) allele, and Self (a_) allele

Possible Allele Pairings: Agouti Rabbits (AA, Aa), Self Colored Rabbits (aa)

The A-Series of genes has only two possible possibilities in NZ rabbits, agouti or self. If one dominant agouti (A_) allele is present you get a rabbit with agouti characteristics, if two recessive agouti (a_) alleles are present you get a self colored rabbit. Because the breeding of LER and Luna continue to produce some self colored (black) rabbits with steel tips then the both must carry the (Aa) pairing. So our first gene for these two rabbits is complete.

Our NZR buck 'LER's' Basic Genome: Aa, B_, C_, D_, ee, enen, ww, +++

Our NZW doe 'Luna's' Basic Genome: Aa, B_, cc, D_, E_, enen, W_,

B-Series Of Genes: Black (B_) allele or Brown (b_) allele

Possible Allele Pairings: Black Colored Rabbits (BB, Bb), Brown Colored Rabbits (bb)

This gene then determines whether the rabbits base coat color is black or brown. Because the black (B_) allele is dominant over the brown (b_) allele, black is the most common color. The allele pairings (BB) or (Bb) will always produce a black, while the recessive (bb) allele pairing will always produce a brown rabbit. Because there are no brown colored NZ rabbits, I will go out on a limb here and say that both LER and Luna carry the (BB) allele pairing. It is possible that one of rabbits carries the (Bb) allele pairing, but one of them is a (BB) for sure, I just do not know which one at this time.

Our NZR buck 'LER's' Basic Genome: Aa, BB, C_, D_, ee, enen, ww, +++

Our NZW doe 'Luna's' Basic Genome: Aa, BB, cc, D_, E_, enen, W_,

C-Series Of Genes: Complete (C_) allele, Incomplete (c_) allele

Possible Allele Pairings: Complete Colored Rabbits (CC, Cc), Albino Rabbits (cc)

The C-series of genes determines whether a rabbits coat has complete color or no color. The dominant (C_) allele allows all four of the dark and all three of the yellow pigments to be present in the hair shaft. This allows for full color development of the rabbits coat and works with the E-series of genes and their alleles to produce ticking or steel tipped colors in rabbits that carry the agouti (A_) allele. A NZ rabbit with two recessive (c_) allele's is classified as an albino (white rabbit with red eyes). Because multiple pairings of LER and Luna have never produced any white kits, and you have to have a (cc) allele pairing to produce white kits, we know that LER carries a (CC) allele pairing. If he carried the (Cc) allele pairing, eventually they would produce a white kit (cc), but this has never happened.

Our NZR buck 'LER's' Basic Genome: Aa, BB, CC, D_, ee, enen, ww, +++

Our NZW doe 'Luna's' Basic Genome: Aa, BB, cc, D_, E_, enen, W_,

D-Series Of Genes: Dense (D_) allele or Dilute (d_) allele

Possible Allele Pairings: Dense Coat (DD, Dd), Dilute Coat (dd)

The D-series of genes determines the depth of color of the coat of the rabbit. Rabbits with at least one dense (D_) allele have full color shades that are are darker (black or chestnut), and generally have brown eyes. Rabbits with a dilute (d_) allele have a lighter more sedated or dilute colored pigment in the hair shaft causing the coat to be lighter in color. Unfortunately I have no definitive way to determine the 'D' allele pairings of these two rabbits. All of their kits appear to have a nice dark definitive coats, so I am leaning towards (DD) for both, but because I confirm that I will leave them as undetermined (D_).

Our NZR buck 'LER's' Basic Genome: Aa, BB, CC, D_, ee, enen, ww, +++

Our NZW doe 'Luna's' Basic Genome: Aa, BB, cc, D_, E_, enen, W_,

E-Series Of Genes: Steel Extension (Es_) allele, Normal Extension (E_) allele,

Non-extension (e_) allele

Possible Allele Pairings: Steel Tipped Rabbits (EsEs, EsE, Ese), Black Rabbits (EE, Ee), Red Rabbits (ee)

The (Es_) allele works in combination with the agouti (A_) allele and is responsible for producing the ticking or steel patterns (Gold or Cinnamon tipped). So in order for a NZ doe to produce kits with steel characteristics (tipped hair coloring) either the buck, doe, or both must carry an agouti (A_) allele. If both rabbits in the breeding pair carry the self colored (aa) allele pair, they cannot produce kits with steel tipped fur. Because our NZR buck 'LER' carries a non-extension (ee) gene, and NZR's also carry the dominant agouti (A_) allele, and we get some steel tipped kits, then we know our NZW doe Luna must carry the steel extension (Es) in her basic genome. In addition, because all NZR rabbits are (ee), and this pairing never produces any litters with red rabbits then her 'E' gene pairing must be (EsE).

Our NZR buck 'LER's' Basic Genome: Aa, BB, CC, D_, ee, enen, ww, +++

Our NZW doe 'Luna's' Basic Genome: Aa, BB, cc, D_, EsE, enen, W_,

W-Series Of Genes: Normal Width (W_) allele, Double Width (ww) allele

Possible allele Pairings: (WW), (Ww), and (ww)

The dominant normal width (W_) gene produces a yellow or white agouti color band in the hair shaft producing a normal coloring. The recessive double width (ww) gene doubles the width of the yellow or white agouti band in the hair shaft causing the rabbit to have the characteristic agouti patterns typical of the new Zealand Red. Because of NZR buck LER carries the double width (ww) agouti gene which produces the standard agouti patterns around the eyes, triangle at the nape of the neck, feet, legs, ear, and inside of the belly. However, none of the the steel tipped kits exhibit these patterns, and this pairing has never produced any litters with red rabbits Therefore Luna must carry a (WW) allele pairing.

Our NZR buck 'LER's' Basic Genome: Aa, BB, CC, D_, ee, enen, ww, +++

Our NZW doe 'Luna's' Basic Genome: Aa, BB, cc, D_, EsE, enen, WW,

For this particular pairing of rabbits, fleshing out their genome was pretty straightforward. The whole process is simply a matter of looking at the types of offspring that this breeding produces. If Luna was bred to a white buck, then I would have been unable to unravel both her or LER's color genome as all the pigments in their offspring would be suppressed by the (cc) allele which produces albinos, aka. Ruby-eyed Whites (REW). Once we know the genome of the parents, we can then produce an accurate genome of their offspring.

Their last litter complete genome (almost):

2 - Chestnut Agouti's: Aa, BB, Cc, D_, Ee, enen, Ww

5 – Black Cinnamon Tipped Steels: aa, BB, Cc, D_, Ese, enen, Ww

Conclusion

I know this may seem like a lengthy process, but it is fairly easy, and once you have done it a few times it goes really fast. You just have to understand that determining the color genome of some rabbits is easier than others, and you need to look at more than one litter to be able to accurately determine the genetic color makeup of the rabbits in your herd. If you have read all three of the articles in this series you may think to yourself, I am just not interested in knowing this. That's fine, but remember if you what to be able to produce consistent litters of specific colors to sell as breeding stock, knowing the genetic color makeup of your herd will help you to become more successful.

The more genetic variables you have in your herd, the harder it is to consistently reproduce the desired characteristics in your herd's offspring whether it be size, shape, and or color. When adding new livestock to your herd, a pedigree helps because it usually contains the basic weight and color characteristics of the rabbits ancestors. Just remember however that a pedigree does not always guarantee you quality, that final determination must be made by you when you examine the rabbit prior to purchase. As always, if you have found this article interesting or informational please share it with your friends. Don't forget to follow us on Facebook or on Google+ for the latest articles on our blog related to raising your own meat rabbits.

Other Related Articles:

New Zealand Rabbit Genetics Part 1: Dominant And Recessive Genes.

New Zealand Rabbit Genetics Part 2: It's in the Genes.

Additional References:

Stewart, Eric, Rabbit Color Genetics (ARBA Article Of The Month 2012)

Rabbit Genetics: The Basics Are Easy To Understand.

Rabbit Genetics: A Genetics Primer.

Rabbit Color Genotypes Chart: 144 rabbit Color Coat Colors and Their Genotypes.

British Rabbit Council (BRC) 

New Zealand Rabbit Genetics: Coat Color: It's In The Genes

To reiterate what we talked about in my first article on dominant and recessive genes, a rabbits chromosomes are strings of DNA that act as building blocks or blueprints that determines the final characteristics or traits of the animal. Each chromosome has an individual spot or location (loci) in which a specific gene is attached. The buck and doe each contribute one part of their chromosome's to their offspring. When these two chromosomes combine together they form a chromosomal pairing in which each chromosome supplies one allele to make a genetic pair. These allele pairings then act together, alone or in combination with other alleles and gene modifiers to determine a rabbits overall coat and hair appearance.

In this second article of the series, we will be examining how a New Zealand (NZ) rabbits hair color is determined by a combination of multiple genes and their allele pairings. The combination of allele pairings of each gene act in conjunction with other genes to produce a variety of different colors and patterns. A rabbit has only two possible pigments that can be expressed in its hair, dark brown and yellow. The absence of both pigments results in albinism (white fur). All of the possible hair colors in a rabbit's hair shaft are simply combinations of these pigments or lack thereof. This genetic expression can appear on the same or different hairs, in certain patterns, and in different intensities. Because we are going to be looking specifically at the genetic makeup of the New Zealand breed, there will be some genetic color traits found in other breeds that are not present in New Zealand's.

In NZ rabbits, as with most breeds, there are 10 genes (A, B, D, C, E, En Du, Si, V and W) each with multiple alleles (gene variants) that determine the primary color and depth of a rabbit's coat. There are other factors and color modifiers (rufus modifiers, plus/minus) that work in combination with these genes and their allele's to control the intensity and or depth of certain colors and or patterns. These color modifiers are not single genes, but multiple ones that work in combination to create a specific color pattern.

A-Series Genes: Agouti (A_) allele, and Self (a_) allele

Possible Allele Pairings: Agouti Rabbits (AA, Aa), Self Colored Rabbits (aa)

The A-Series of genes has only two possible possibilities in NZ rabbits, agouti (A_) or self (aa). While other breeds carry the Tan (a^t) allele, purebred NZ rabbits do not.

The agouti (A_) allele has complete dominance over the self (a_) allele. It produces a rabbit with a white or cream (depending on modifiers) hair color on the belly, eye circles and inner ear, and the rest of the hairs will be banded. So when you separate the hairs and closer examine them you will usually see three distinct color rings. The outermost color ring is determined by the B-series and D-series genes and their allele's (see below), the middle ring will generally be white to bright yellow, and the bottom ring will be white to slate gray. This genome is responsible for the “natural” or “normal” color of wild rabbits. In New Zealand rabbits this color pattern is often called chestnut.

When two recessive self (aa) alleles are paired together it produces a NZ rabbit that has a coat completely made of one color. Therefore, a rabbit with a self (aa) allele pairing is bred with another rabbit with the self (aa) allele pairing, they should never produce any agouti offspring. If you are looking to breed for consistency of color in your heard, then it is important that you acquire both male and female rabbits with a self (aa) gene. The self color is sometimes called 'solid' by some breeders.

B-Series Of Genes: Black (B_) allele or Brown (b_) allele

Possible Allele Pairings: Black Colored Rabbits (BB, Bb), Brown Colored Rabbits (bb)

Almost all rabbits regardless of breed will carry are either the black (B_) or brown (bb) allele. The B-series gene then determines whether the rabbits base coat color is black or brown. Because the black (B_) allele has complete dominance over the brown (b_) allele. Black is the most common color, as the allele pairings (BB) or (Bb) will always produce a black or blue rabbit (see NZ Blue later in this article), while the recessive (bb) allele pairing will always produce a brown rabbit. Therefore, if two rabbits both have the recessive brown (bb) allele pairing they will never produce any black offspring. If any pair of rabbits produce brown offspring, then both the buck and doe must have had at least one brown (b_) allele.

Some rabbits look like they have a brown coat, but they are not really brown. The most common example of this is the agouti (see above), sometimes called the “natural” or “normal” color of rabbits. While an agouti or cottontail rabbit may appear to be brown in color, their coat is actually made of different layers of banded phoemelanin (yellow) and eumelanin (dark brown) hairs. This combination of colors may give the appearance of brown rabbit, but a brown rabbit must have the (bb) allele pairing.

C-Series Of Genes: Complete (C_) allele, Incomplete (c_) allele

Possible Allele Pairings: Complete Colored Rabbits (CC, Cc), Albino Rabbits (cc)

The C-series of genes determines whether a rabbits coat has complete color or no color. The complete (C_) allele is dominate to the incomplete (c_) allele. The dominant complete (C_) allele allows all four of the dark and all three of the yellow pigments to be present in the hair shaft. This allows for full color development of the rabbits coat and works with the E-series of genes and their alleles to produce ticking or steel tipped colors in rabbits that carry the agouti (A_) allele. The New Zealand Black (NZB) is an example of a rabbit that carries the complete dominant allele. When a rabbit receives two incomplete or recessive (c_) alleles from it's parents it is classified as an albino. The recessive (cc) allele pairing not only blocks all the color of all the pigments along the hair shaft, it blocks all expression of color in the rabbit producing a white rabbit with red eyes (REW). The New Zealand White (NZW) rabbit because it has the recessive (cc) allele pairing has a coat as well as eye color that lacks any color pigment. They are in essence albinos, however they are carriers of all the other color allele's you just cannot physically see them. You may however see some of these allele's show up in their offspring when bred to a non-white rabbit.

D-Series Of Genes: Dense (D_) allele or Dilute (d_) allele

Possible Allele Pairings: Dense Coat (DD, Dd), Dilute Coat (dd)

The D-series of genes determines the depth of color of the coat of the rabbit. Dense (D_) has complete dominance over dilute (d_), rabbits with at least one dense (D_) allele have full color shades that are are darker (black or chestnut), and generally have brown eyes. Rabbits with a dilute (d_) allele have a lighter more sedated or dilute colored pigment in the hair shaft causing the coat to be lighter in color. Any combination of allele pairing in which there is at least one dense allele (DD, Dd) will produce a rabbit with a dense coat with (DD) being the darker of the two. Rabbits with the dilute (dd) pairing have the lightest or most dilute coat color. If you want to increase the depth of coat color in your rabbit's bloodline, then breeding a rabbit with a (DD) allele can help you accomplish this while breeding a rabbit with a dilute (dd) allele pairing will soften or mute the color.

When a rabbit with a dilute (dd) allele pairing also carries one of the black (BB, Bb) allele pairs, the coat color is changed or diluted from black to blue and causes the eye to be gray-blue. So we see that the B-series gene and the D-series gene when combined can produce a totally different color of rabbit. Breeders of NZ's have been developing a genetic line of New Zealand Blue's (NZBL) for a few years now, but this color has not been approved by the ARBA so there is no breed standard as of yet. Therefore any rabbit that is blue in color must have a complete dilute (dd) allele pairing.

E-Series Of Genes: Steel Extension (Es_) allele, Normal Extension (E_) allele,

Non-extension (e_) allele

Possible Allele Pairings: Steel Tipped Rabbits (EsEs, EsE, Ese), Black Rabbits (EE, Ee), Red Rabbits (ee)

The E-series of genes work in combination with the C-series of genes and the rufus modifier to make a variety of small and subtle changes to the pigments in the rabbits hair shaft that determines it's overall coat color. There is a lot going on with this gene series; not only are there six possible allele pairings (EsEs, EsE, Ese, EE, Ee, and ee), there is more than one dominant gene although there is a specific order of dominance that has to be taken into consideration.

In E-series genes, the steel extension (Es_) allele is dominate to the normal extension (E_) allele, which is dominant to the non-extension (ee) allele. The (Es_) allele works in combination with the agouti (A_) allele and is responsible for producing the ticking or steel patterns (Gold or Cinnamon tipped) in some NZ rabbits. This combination of (A_, Es_) alleles work together to accentuate or darken the characteristic agouti type landmarks (eye circles, triangle at nape of neck, feet, legs and the inside of the ears) of some rabbits. So in order for a NZ doe to produce kits with steel characteristics (tipped hair coloring) either the buck or the doe must carry an agouti (A_) allele. If both rabbits in the breeding pair carry the self colored (aa) allele pair, they cannot produce kits with steel tipped fur. In NZ rabbits steel-tipped kits are most often seen when a NZR (which carries the agouti gene) is bred with a self (aa) colored rabbit. Obviously a NZ chestnut agouti has the potential to produce steel tipped kits, but most breeders who sell breeding stock do not keep chestnuts as part of their breeding program.

The normal extension (E_) allele allows the complete expression of dark black/brown pigment in the hair shaft (New Zealand Black). You have to remember while the (E_) allele allows the complete expression of the black/brown color, it is not the dominant allele here, rather it is recessive to the steel (Es_) allele that is the most dominant allele of the series.

While the (E_) allele allows complete expression of the black/brown color, the non-extension (e_) allele when paired (ee) together removes or suppresses all or most of the black or brown pigment in the hair shaft leaving yellow or orange producing a New Zealand Red (NZR) rabbit.

En-Series Of Genes: English Spotting (En_) allele, Self Colored (en_) allele

Possible Allele Pairings: Charlie Pattern (EnEn), Broken Pattern (Enen), and No Pattern (enen)

In the En-series of genes (sometimes called “plus/minus” or “blanket/spot”), the English spotting (En_) allele is dominant to the self colored (en_) allele. The (Enen) allele pairing produces normal spotting of the rabbits coat, rabbits with this allele pairing are known as 'brokens'. The (EnEn) gene pairings produce less spotting of the rabbits coat than the (Enen) allele pairings, with the focus of the spotting generally around the head area. Rabbits with the (EnEn) allele pairing are known as 'charlies'. The final possible allele pairing is (enen) which as mentioned causes the hair to have normal coloring without spotting.

In addition, the allele pairings of En-series gene work in combination with the allele pairings of the C-series gene and other color markers to make a variety of small and subtle changes to the color patterns seen in NZ 'broken' and NZ 'charlie' rabbits. The amount and location of the spotting in 'broken' and 'charlies' can also be affected by other color modifiers.

The Other Genes (Du Si, V, and W)

Du-Series Of Genes: Absence of Dutch pattern (Du_) allele, White Belt Dutch Pattern (du_) allele

Possible Allele Parings: Solid Color Rabbits (DuDu), (Dudu), Dutch Pattern Rabbits (dudu)

The (Du_) color gene represents the Dutch color pattern. In a Dutch pattern the front of the face , front part of the body, and rear paws are white, the rest of the rabbit has colored fur. The Dutch pattern (Du_) allele is dominant to the white belt Dutch pattern (du_) allele. The (DuDu and Dudu) allele pairings are present in solid colored rabbits causing no dutch patterns. All pure breed NZ rabbits are (DuDu). Since we are specifically talking about genetic coloring and patterns in NZ rabbits, this is all we need to know about this gene.

Si-Series Of Genes: Non-Silvering (Si_) allele, Silver (si_) allele

Possible Allele Parings: No Silver Color (SiSi), Silver colored tips (sisi)

The Si-series of Genes is determines whether the rabbits coat has white and/or silver tipped hairs intermingled throughout the rabbits coat. The (Si_) allele is dominant to the (si_) allele. Rabbits with the (SiSi) allele pairings have normal colored coats (no white or silver tipped hairs), while the recessive (sisi) allele pairing produces white and silver tipped hairs intermingled throughout the rabbits coat. All pure breed NZ rabbits have the normal (SiSi) allele pairing and therefore have no white or silver tipped hairs caused by this Si-series gene. Since we are specifically talking about genetic coloring in NZ rabbits, this is all we need to know about this gene.

V-Series Of Genes: Normal Coat (V_) allele, No Color (v_) allele

Possible allele Pairings: Normal coat (VV), Vienna Carrier (Vv), Blue Eyed White (vv)

The V-series of gene (a.k.a Vienna White) produces a rabbit with a normal coat color. As with most allele's the (V_) allele is dominant to the (v_) allele. Almost all rabbits carry the (VV) gene pairing which produce a normal coat color. The recessive (vv) gene pairing produces a blue-eyed white (BEW) rabbit, while the (Vv) pairing indicates that the rabbit is a carrier for the Vienna White gene. All NZ rabbits carry the (VV) gene, there are no blue-eyed NZ rabbits so none of the breed can carry the (Vv) or (vv) gene pairing. Since we are specifically talking about genetic coloring in NZ rabbits, this is all we need to know about this gene.

W-Series Of Genes: Normal Width (W_) allele, Double Width (ww) allele

Possible allele Pairings: (WW), (Ww), and (ww)

The dominant normal width (W_) gene produces a yellow or white agouti color band in the hair shaft producing a normal coloring. The recessive double width (ww) gene doubles the width of the yellow or white agouti band in the hair shaft causing the rabbit to have the characteristic agouti pattern areas such as: eye circles, triangle at the nape of the neck, feet, and legs, as well as the inside of the ears and belly (typical of the new Zealand Red).

Modifier Genes

The Rufus Modifier (polygene):

It is unique in that it is a stand alone gene and does not rely on any other particular allele. As it's name implies, this gene modifier works in combination with other genes to intensify the red/orange color of the agouti coat in New Zealand Red (NZR) rabbit's. A NZR rabbit with multiple rufus modifiers will have a darker, richer color red coat. A NZR with fewer rufus modifiers will have lighter, duller red color. The rufus modifiers are denoted as a number of plus (+) signs at the end of the basic genome of red colored rabbits.

So here is where it gets a little sketchy. Most of the information I can find simply lists what the rufus polygene does, but does not give a definite idea of the number of rufus modifiers found in NZ rabbits, however my best educated guess is that there are five. So how did I come to this conclusion? The British Rabbit Council (BRC) actually lists the genome and breed standard for red rabbits on there website as: A_B_C_D_ee +++ rufus modifiers. From this information along with other information I have read, I believe that the NZR can have up to five rufus modifiers (+++++) with three (+++) being in the middle or the breed standard. If this is the case, then a NZR rabbit with five (+++++) rufus modifiers would have the most intense red color, and a NZR with two (++) or less would have a very light washed out color red.

Most Intense Red Color: (+++++)

Balanced Red Color: (+++)

Weak Red Color: (+) or (++)

Plus/Minus Modifier Genes

The plus/minus modifier genes work with the En, Du, and V genes to increase or decrease the amount of spots or patterns of a rabbits coat. The more plus modifiers that rabbit has, the more spots or colored hair pattern they will have, the more minus modifiers your rabbit has, the fewer amount of spots or colored hair pattern they will have.

Color Intensifier Modifiers

The color intensifier modifiers. These modifiers can either darken the spots of color and or the overall color of the rabbits coat, or lighten it to a more diluted shade. I will have to admit that I cannot find any additional information on what particular types of color intensifier modifiers there are New Zealand rabbits. Perhaps if I purchased a book that does a through in depth study of rabbit genetics it would mention what exactly these modifiers are, but at this point this is all the information that I could find on the subject.

New Zealand Rabbit Breed Basic Genome or Genotypes

Below are the listed basic genomes or genotypes for the NZ breed of rabbits with all 10 color genes represented. As all NZ rabbits carry the (DuDu), (SiSi) and (VV) allele pairings you could drop these from the listing (must people do) but for the purposes of this article, I wanted to try and give your the most information possible regarding the breed.

Agouti (Chestnut): A_, B_, C_, D_, E_, En_, DuDu, SiSi, VV, W_

Black: aa, B_, C_, D_, E_, En, DuDu, SiSi, VV, W_

Blue: aa, B_, C_, dd, E_, En_, DuDu, SiSi, VV, W_

Red: A_, B_, C_, D_, ee, En_, DuDu, SiSi, VV, ww +++

White: A_, B_, cc, D_, E_, En_, DuDu, SiSi, VV, W_

The Brokens:

Black: aa, B_, C_, D_, E_, Enen, DuDu, SiSi, VV, W_

Blue: aa, B_, C_, dd, E_, Enen, DuDu, SiSi, VV, W_

Red: A_, B_, C_, D_, ee, Enen, DuDu, SiSi, VV, ww +++

The Charlies:

Black: aa, B_, C_, D_, E_, EnEn, DuDu, SiSi, VV, W_

Blue: aa, B_, C_, dd, E_, EnEn, DuDu, SiSi, VV, W_

Red: A_, B_, C_, D_, ee, EnEn, DuDu, SiSi, VV, ww +++

Conclusion

So there are 10 color genes plus a variety of color modifiers that contribute to make up your rabbits coat color. The reality of the NZ rabbit makeup is that since (according to my research) all NZ rabbits carry the (DuDu), (VV), and (SiSi) allele pairings, most people do not examine these genes when they are determining the genome or genotype of the NZ rabbit. It was goal in this article however to give you the most in depth information possible so that you could examine your livestock and begin to understand the genetic makeup of the NZ rabbit. In the third and final article of the series 'Putting It All Together', I will show you how to put this information together to determine the possible genetic genome of your rabbits without having to do any DNA testing. It may not be as accurate as a DNA test, but it the tried and true technique that has been used by breeders for hundreds of years, way before DNA was even discovered.

Now I am not a geneticist, rather just a humble breeder of New Zealand rabbits that happens to have a medical background so do understand something about genetics. Having said that, I have tried to make sure the information provided in this article is as accurate as possible. If you see an error in my conclusions and have additional information regarding the subject, please feel free to leave me feedback so that we can discuss your findings. As always, if you have found this article interesting or informational please share it with your friends. Don't forget to follow us on Facebook or on Google+ for the latest articles on our blog related to raising your own meat rabbits.

Other Related Articles:

New Zealand Rabbit Genetics Part 1: Dominant And Recessive Genes.

New Zealand Rabbit Genetics Part 3: Putting It All Together.

Additional References:

Stewart, Eric, Rabbit Color Genetics (ARBA Article Of The Month 2012)

Rabbit Genetics: The Basics Are Easy To Understand.

Rabbit Genetics: A Genetics Primer.

Rabbit Color Genotypes Chart: 144 rabbit Color Coat Colors and Their Genotypes.

British Rabbit Council (BRC) Website.

New Zealand Rabbit Genetics: Dominant And Recessive Gene's

Just as in humans, a rabbits chromosomes are strings of DNA that act as building blocks or blueprints that determines the final characteristics or traits of the animal. Each chromosome has an individual spot or location (loci) in which a specific gene is attached. When two chromosomes combine together they form a chromosomal pairing in which each chromosome supplies one gene to make a genetic pair. These gene pairings then act together, alone or in combination with other genes and modifiers to determine a rabbits overall coat and hair appearance. To be more accurate, each gene is further categorized by it's specific function or property known as alleles (which are different versions of the same gene). So for the remainder of these three articles we will refer to the individual gene's variations as alleles.

This is of course a pretty basic statement, and you could examine the structure of DNA and chromosomes until your eyes glaze over, but suffice it to say all you need to know is that both the buck and the doe each contribute one chromosome to their offspring. These chromosomes when paired together each supply one part of a gene (allele) pair that individually or in combination with other allele's determine their offspring's appearance (body shape, ear size, coat color and patterns etc…). Before we get into the second article in this series, you need to understand a few terms as well as understand how the gene's allele's when paired together work to determine your rabbits final coat color and pattern characteristics.

First of all, every allele is classified as either 'dominant' or 'recessive'. For scientific notational purposes all allele's classified as dominant are represented by a capitol letter, while their recessive counterpart(s) are represented by a uncapitalized letters. A dominant allele is just that, it dominates the pairing. For any pairing in which there is at least one dominant allele, the characteristics of that dominant allele almost always supersedes those of the recessive allele. Most dominant allele's express themselves completely suppressing any characteristics of the recessive allele. When this happens it is called complete dominance. However, recessive allele's can modify the expression of the dominant allele making subtle changes to the overall genetic outcome. When this happens to relationship of the dominant allele in regards to the recessive allele is called incomplete dominance. In addition, an allele pair can be made up of two recessive allele's which may produce a totally different outcome.

So what exactly does all this dominant and recessive gene mumbo jumbo mean? To keep it simple, a rabbits dominant allele traits are visually apparent over a recessive allele. That means you can see them when you look at the rabbit. A rabbit's recessive allele traits are not visually apparent. That means the characteristics of the allele are there, but you cannot visually see them.

As a quick example of how gene dominance works we are going to examine the B-series gene whose allele pairings are responsible for producing black, blue (we will discuss blue coloring in our second article), and brown hair colors in rabbits. When it comes to color, almost all rabbits will carry either the black or brown allele.

There are only two B-series gene allele's black or brown. The combination of these two allele's determine whether the rabbits base coat color is going to be black or brown. Since black is the dominant allele in this pair it is represented by the capitol letter 'B', because brown is the recessive allele in this pair it is represented by the uncapitolized letter 'b'. As the B-series gene is made up of a combination of these two dominant and or recessive alleles, when writing them we indicate the dominant black allele as (B_), and the recessive brown allele as (b_). We use the '_' to denote the second allele which is absent in a paring when we do not know what it is yet.

As mentioned earlier, the buck and the doe each supply one chromosome to their offspring to complete the chromosome's genetic pairing. As the B-series gene has only two allele's black (B_) and brown (b_) there are only three possible allele combinations. Their offspring can have two dominant black allele's (BB), one dominant black allele and one recessive brown allele (Bb), or two recessive brown allele's (bb). Because black (B_) has complete dominance over brown (b_), any combination of these allele's in which there is at least one black allele (BB, or Bb) will result in black offspring. When two recessive brown (b_) alleles complete the pair (bb) then the offspring will be brown.

Terms Or Definitions

Alleles: Are different versions of the same gene that can occupy the same position on a particular chromosome and control the same characteristic such as hair or eye color. Rabbits are diploid organisms because they have two alleles, one at each genetic locus, with one allele inherited from each parent. In our previous example, we examined the B-series gene that could made up of pairs of either black (B_) alleles, brown (bb) alleles or a combination of the two.

Chromosome: A string of DNA made up of individual points (or loci) called genes. Rabbits cells contain two sets of chromosomes, one set inherited from the mother (doe) and one from the father (buck). These chromosomes combine together to make pairs in which they share genes.

Genes: Are the working subunits of DNA. They hold the blueprints or genetic instructions that determine the rabbits genetic makeup (body size, composition, hair color etc.) Genes come in multiple variations called allele's which make up the gene pairing.

Conclusion

This is just a quick example to show you how a chromosome's genes (and all it's allele variants) work together to determine one color aspect of your rabbits potential coat color. Now that you understand the 'lingo' it's time to look at are second article 'New Zealand Rabbit Genetics Part 2: Hair Color: It's In The Genes' for in in depth look at how to determine the color characteristics of your breeding rabbit's and what to expect when you breed specific color combinations of New Zealand Rabbits. I know there may be a lot of new terms that many people are not familiar with when it come to genetics and I will try and keep this information as simple as I can. Maybe the following line drawing will make my ramblings more clear. As always, if you have found this article interesting or informational please share it with your friends. Don't forget to follow us on Facebook or on Google+ for the latest articles on our blog related to raising your own meat rabbits.

In a nutshell:

Two individual chromosomes, each come from each parent.

• These chromosomes combine to make one chromosomal pair in the offspring's cells.
  • This chromosome pair Is made up of multiple genes (A, B, C, D, etc…)
    • These genes are made up of individual genetic variations called allele's.
      • The allele's of the B-series gene that we examined in this article were black (B_) and brown (b_).

Related Articles:

New Zealand Rabbit Genetics Part 2: Coat Color: It's In The Genes.

New Zealand Rabbit Genetics Part 3: Putting It All Together.


Additional References:

Stewart, Eric, Rabbit Color Genetics (ARBA Article Of The Month 2012)

Rabbit Genetics: The Basics Are Easy To Understand.

Rabbit Genetics: A Genetics Primer.

Rabbit Color Genotypes Chart: 144 rabbit Color Coat Colors and Their Genotypes.