The A Locus: Wild, Tanned, and Selfish

This post is Lesson 4 in our Rabbit Genetics Illustrated series. 

Wild, tanned, and selfish could easily describe a good number of people. At this time, you can picture who ever you would like who fits that description if that's what it will take for you to remember what lurks here. However we are talking about rabbits. The A Locus is home to not two but three possible coat patterns. They are Agouti (some times referred to as the wild rabbit coat), Tan, and Self. 

Let's start with the Self rabbits since that is what we have been using in all of our examples so far. A Self rabbit is covered from the tip of it's ears to the tip of it's toes in one single solid colour. It can be any of our four primary colours: Black, Blue, Chocolate, or Lilac. There should be no spots, no shading, no pattern of any sort imposed over this colour. All you see is that colour. 

The Tan gene is responsible for giving us the iconic look of the Otter pattern. The Tan gene spices up the plain Self rabbit by adding a few simple modifications. It turns the fur into a light cream or off-white on: the belly, the inside of legs, underside of feet and tail, under the jaw, inside the ears, around the eyes and nostrils, and slightly at the nape of the neck. All of these light areas are bordered by an orange/tan before blending into the remainder of the coat which remains a solid Self colour. The quality of the pattern can vary from one animal to another. It may be more pronounced and bold or it may be more faint.  On non Diluted rabbits, the border of this pattern is orange/tan in colour. On Diluted rabbits, every part of the rabbit is Diluted and hence the orange/tan border areas turn into a lighter diluted version of itself and will look like a fawn/cream. 

The Agouti gene takes things up one notch further. It takes the Tan patterned rabbit and gives it a banded coat. Now, each hair instead of being only one single colour will display multiple bands or multiple layers of colour all on a single hair. More on this later. The end result is a coat colour that looks like it has been applied with spray paint. 

Agouti is the most dominant out of all three and as such is noted by the capital "A". Agouti is dominant over both Tan and Self. A single copy of "A" automatically turns the rabbit into Agouti. Agouti can carry both Tan and Self.

"AA" would be an Agouti rabbit.
"Aat" would be an Agouti rabbit that carries Tan.
"Aa" would be an Agouti rabbit that carries Self. 

"A_" would be a rabbit that you can see is Agouti, but you do not know if it carries Tan, Self, or neither. 

Tan, often referred to as Otter, is noted by the letters "at". Tan is only dominant over Self. Tan can only carry Self.

"atat" would be a Tan rabbit.
"ata" would be a Tan rabbit that carries Self.

"at_" would be a rabbit that you can see is Tan, but you do not know if it carries Self.

Last but not least is Self. Self is noted by the small letter "a". A Self rabbit can only be "aa" as a single copy of "A" automatically turns the rabbit into Agouti, and "at" is dominant over "a" resulting in a Tan looking rabbit. Self can not carry Agouti and it can not carry Tan.

The above illustration uses a Black Self rabbit as the base coat for our Agouti and Tan patterns. Change the base coat colour, and you change the over all appearance of the rabbit! The main principles of the pattern remain the same. Here are the 12 possible variations of the A Locus using our four primary colours. 

Before we jump to our Punnett squares to see some breeding results, here are a couple things to note. One, if you have an Agouti rabbit and would like to know if it is possibly carrying Tan or Self, you can test breed for that using a Self rabbit. You will see how in a minute. Two, if you breed two Self rabbits, you will never ever end up with either an Agouti or a Tan rabbit, because both Agouti and Tan are dominant over Self and Self can never carry these unseen. This is important to keep in mind because for example in Angoras, people often mistakenly label a Tort rabbit as a Fawn. A Tort (short for Tortoiseshell) is a Self based rabbit. A Fawn is an Agouti based rabbit. If you look on your pedigree and your Fawn rabbit has two Self based parents, you know it can not possibly be a Fawn and is in fact a mislabelled Tort.

Here is what happens when you breed a Self to an Agouti, as well as what happens when you breed a Self to a Tan. 

If you breed a Self to an Agouti that does not carry Tan or Self, all you will get are Agouti babies. 

If you breed a Self to an Agouti that carries Tan, you will get babies that are either Agouti or Tan. 

If you breed a Self to an Agouti that carries Self, you will get babies that are either Agouti or Self. 

If you breed a Self to a Tan that does not carry Self, all you will get are Tan babies. 

If you breed a Self to a Tan that carries Self, you will get babies that are either Tan or Self. 

Continue forward to Lesson 5! 

The C Locus: The Department of Pigment Taxation