Genetics Explained

Mini Lop Color Genetics Explained
Or at least tried to......

     Coat colors are a whole hobby unto themself. You could spend most of your life trying to figure them out and still get surprised now and then. Here is my feeble attempt to portray what I know about colors and hopefully help others that care to know more about them understand them better. This does not cover every gene known to man but covers the basics in Mini Lops. It doesn't cover things like fur type such as Satin, Rex, Angora and patterns not recognized in Mini Lops such as tan, marten and otter. I've been studying this for a year now and sometimes feel as though I've made little progress so bear with me. Email me if I have my facts messed up. Enjoy.

The Letters of the Alphabet....

     Ok so you are interested in genetics and knowing what colors bred together will result in a specific color or what specific colors will result in what possiblities. Maybe you've had something surprising pop up in a litter and don't have a clue what it is so you start to try to figure out genetics. If you are like me when you start seeing things like A_bbc(chl)D_ee your brain normally switches to off and you get overwhelmed trying to make sense of it all. It's actually not that complicated once you get a basic understanding of the different letters, what they represent and how they work. By now I'm sure you know the order of the alphabet, especially since you are reading this... so therefore I can answer the first question. Why did they pick A, B, C, D and E for letters? Well simply because they wanted to start at the beginning and make this as easy and as painless a system for figuring out genetics as possible. Don't switch to another page now. Understanding these letters really is quite easy once you look into it. Let's jump into the alphabet soup and start at the very beginning with none other then the letter A.

The A Series....

     The A genes represent the Agouti coloring of a rabbit.  Wild rabbits are all Chestnut Agoutis. Their coat color is completely dominant. If you blow into their fur you will see rings of color. Starting with white, going to orange, then brown and then black. This is what is reffered to as agouti. Agouti is banded colors on the hair shaft from the skin to the tip. The dominant genes are represented by capital letters. Therefore the capital "A" represents agouti. A lowercase "a" however represents a self color. Self is where the color is usually just one solid color. There is no banding noticable.

     Of course it's slightly more complicated then just "A" and "a". Genes come in sets of two. One from the father and one from the mother. So every rabbit has a set of two of the A series genes. Here is what they can look like. AA, Aa and aa. If you do not know what the gene really is the underscore sign is often used in place of an unknown gene. Therefore most agouti rabbits are represented as A_. We know they are Agouti so therefore they have to have at least one dominant Agouti gene (A) but we do not know beyond that what the second gene is unless we look at their pedigrees and their offspring. They could carry the recessive "a" gene from one of their parents but you will not know that unless you breed them and get completely recessive babies or if one of the parents was completly ressessive. If they did it would look like "Aa".

     If you get a rabbit that is a recessive self color then it always has two recessive genes.  If it had one recessive and one dominant gene the dominant gene would always show. For sake of making it easy to understand, the dominant genes always come before the recessive genes in the genetic code when written. Therefore their capital and lowercase letters that represent them have the same rule. You will never see an Agouti rabbit that carries the recessive self gene written as "aA". It will always be "Aa".

     Here is a list of what I hopefully have been able to describe with satisfactory results.

A = Agouti (Dominant Gene)
a = Self (Recessive Gene)

AA = Agouti (Completely Dominant)
Aa = Agouti (One Dominant, One Recessive)
aa = Self (Totally Recessive)

Here is a list of what you would get when breeding different cobinations of the genes above.

Parent 1: AA  X Parent 2: AA = All offspring AA
Parent 1: AA X Parent 2: Aa = Half of offspring AA and half Aa.
Parent 1: AA X Parent 2: aa = All offspring Aa.
Parent 1: Aa X Parent 2: Aa = Quarter offspring AA, half Aa and quarter aa.
Parent 1: Aa X Parent 2: aa = Half offspring Aa, half aa.
Parent 1: aa X Parent 2: aa = All offspring aa.

Along with the A series is the tan gene. It is represented by the a(t) symbol. It is dominant to a but is recessive to A. To very simply put it, it makes an almost self colored rabbit with a light belly, nose, eye and ear markings like that of an agouti. It also has some ticking on it's fur. There is not Agouti banding in the fur however.

Here it is in the list of Dominance.

A = Agouti (Completly Dominant)
a(t)=Tan (Dominant to a, Recessive to A)
a=Self (Completely Recessive.

On to Punnet Squares to reduce confusion.

Another less confusing way to look at all this is through the use of a tool called "Punnet squares". Use them with all of the different genes in the future. Here is an example below of how they work.

In box 1 we first enter parent 1's genes (Highlighted in Red). In this case parent one is "Aa" (One dominant agouti gene and one recessive self gene).
1
A
a
In box two we entered Parent 2's genes (Now highlighted in red). For sake of demonstration this parent will also be "Aa" (One dominant agouti gene and one recessive self gene).
2 A a
A
a
In box three we now take parent 1's genes and copy them to the right to show the first set of genes the offspring will have.
3 A a
A A A
a a a
Now we move on to box 4 to get our final results and add the second parents genes. (And remeber to keep those dominant capital letters in front of those recessive lowercase ones.)
4 A a
A AA Aa
a Aa aa
The final outcome is a quarter of the offspring will be AA (completely dominant agouti genes), half will be Aa (One dominant agouti and one recessive self gene) and a quarter will be aa (Completely recessive self).
5 A a
A AA Aa
a Aa aa
Use this Punnet Square technique will all the gentics. It works with them.

Those Bothersome B's...

Get ready for a shocker. The B series is extremely easy to understand. Are you ready for it? Here goes.

There are only 2 colors in rabbits. Yes I know that there are lilac torts, chestnut agoutis, oranges, chinchillas, frosted pearls, sables and the list goes on. But there are only 2 colors. Here's how.

The B gene is responsible for two colors. Black and Chocolate. The dominant wild rabbit's genetic code is AABBCCDDEE and is a black chestnut agouti. But wait, a chestnut agouti is a brown rabbit you may say. True but look closely at the tips of the fur on a wild rabbit and you will see they are black. The dominant "B" gene is therefore responsible for the color black. The Recessive "b" gene is responsible for brown, otherwise refered to as chocolate. If you get a Chocolate Chestnut Agouti (A_bbC_D_E_) the tips of the fur will be brown and the rabbit will also have a brown base coat. You get the same thing with chocolate chinchillas and all other agoutis. Selfs will also have a brown based fur coat with out the dominant B (black) gene.

If you have a non agouti rabbit with the Dominant gene "B_" you will have a black based rabbit or some genetic varient of this color. If you have a completely recessive "bb" you will have a chocolate rabbit or some genetic varient of this particular color. If the rabbits are Agouti then you will have both of the same things apply but the fur will have a banded hair shaft and can appear to be a number of different colors. Just remember that all the other genes will take these two colors and distort them into what appears to be some other color but there are only 2 true colors.

BB = Black (Completely dominant)

B_ = Black (One dominant gene, one unknown gene)

Bb = Black (One dominant black gene, one recessive chocolate gene)

bb = Chocolate (Completely recessive)

The same way the genes are passed on with the "A" genes (One from each parent) are also applied here. If the rabbit has a completely ressive parent then it obviously carries a resessive gene. If it has two completely dominant parents then it is always dominant. If it ever produces a rabbit which is recessive in color then it is either completely recessive or carries a recessive gene. The rabbit which it was bred to also must carry a recessive gene to have a completely recessive baby.

The Confusing C's...

I'll be the first to admit the "C" series is a bit confusing and intimidating. There are a lot of little "subgenes" as I like to call them that affect this particular gene. To start out with the "C" gene is the dominant full color gene. The "c" gene is the completely recessive "no color" gene. The "c" gene acts as a white blanket on a rabbit and covers up it's real color while the dominant "C" gene allows the full color to show. There are other genes in this series that do some other strange things to color as well. Each is in order below by their dominance. Each gene is only recessive to the genes above it and dominant to the genes below it in this list.

C = Completely dominant full color gene

c(chd) = Turns all yellow pigment in fur completely white.

c(chl) = Responsible for the shading on a rabbit. Eliminates yellow and turns black to brown.

c(ch) = Pointed gene. Limits color to only the nose, eyes, ears, feet and tail. Heat sensative gene.

c = Completely recessive no color (or albino) gene

Now remember each combination above acts as a single gene because in all reality it is. The rabbit gets one set from each parent. There for it is possible to have any combination of two of the above genes. Which one you will be able to tell will be the one that is the most dominant. If you get a Ruby Eyed White rabbit (REW or incorrectly Albino) then you know both the genes are "cc". It got one "c" gene from each parent. If you get a pointed rabbit then you know it got the c(ch) gene from at least one parent and the other parent either gave a "c(ch)" or a "c" gene. Any other gene would be dominant to this combination and you would therefore not have a pointed rabbit. The rest of the genes in this category work in this order.

The Decisive D's...

You remember how I said their were only two colors? Well this gene takes those two colors and turns them into four. It's very simple to explain. The dominant "D" means undiluted color. The rabbit will be either a black base or a chocolate based rabbit depending on whether it has the dominant or recessive "B" genes. The recessive "d" gene when doubled up with another "d" gene will dilute those to colors to blue and lilac respectively. It's really simple.

Dominant "D_" combination

Black = Black

Chocolate = Chocolate

Recessive "dd" combination

Black = Blue

Chocolate = Lilac

And last but certainly not least...

The Enraging E's...

The only other gene that gave me more problems was the "C series" genes. These genes are fairly simple except they do break the rule in one spot where a dominant gene sometimes acts as a recessive. This is again another gene with more then one variation. Below they are shown in order of dominance.

Es = Steel gene. Responsible for color of tipping on ends of fur. There are two colors which this will create on the ends of the fur as well. One is gold and the other is silver. This is the only dominant gene that can be "hidden". A rabbit can have it and not show it. This one gene is slightly more complicated then what I've just told you but for sake of not going into to much detail it controls the "tipping" on the fur.

E = Normal extension gene. Allows fur to have color banding at a set distance apart and allows all the color to be on a hair.

ej = Responsible for the Harliequin gene which causes the "B" gene colors (Black and Chocolate) to bunch together in patches on the body. In a broken rabbit this results into a Tri colored rabbit. In a solid rabbit it results in a Harliequin. Possible color combinations for a tri are orange/black/white, orange/chocolate/white, fawn/blue/white, and fawn/lilac/white. A magpie is a result of the ej gene in combination with the c(chd) and c(chl) there for turning the orange fur to white. This will result in a silver/white rabbit with black patches.

e = Extended extension gene. Broadens the color bands in the fur so that they extend beyond the length of the fur. Thereby turning a chestnut agouti red, orange or fawn. Sooting in these colors is a result of the "ee" combination not having it's modifiers extended enough so some of the brown from the fur tips the ends. Also the color of the fur depends on how close together the rufus modifiers are. If they are closer then the rabbit will appear darker. For instance a red instead of an orange. Genetically they are the same thing and have the same alphabetical makeup but the modifiers are the determining factor in the color difference. In other breeds this particular gene varies a little. Red, Orange and fawn are not the same genetically in some other breeds but for Mini Lops they are.

The ej combination is something I have just started studying. It's a bit tricky and needs a lot more explination then I have right now but I will update it when I figure it out myself. Mostly you will not find tri or harliquin Mini Lops so you probably won't have to deal with this particular gene.

I will also attempt to learn about the other genes that affect other things besides color and I will learn more on the coat pattern genes such as tan, marten, and otter. I've seen tan and otter used interchangably but I'm not sure if this is correct. I will do more studying. I also haven't touched on fur type such as Normal, Rex, Satin, Angora, etc.

Hopefully this has helped answer a few questions. I will be updating this as I learn more.

Welcome to Honeysuckle Rabbitry!

ARBA Inc. Registered breeder of pedigreed, show quality mini lop rabbits in a variety of colors. Registered Rabbitry # A197. Member of ARBA, MLRCA, EMRBA and WMRBA.