There are five basic sets of genes that determine the look and color of your rabbit, and several lesser gene sets. The basic genes are A Agouti, B Black/Brown, C Color Saturation, D Dilution of Color and E Extension of color. Other gene sets include V Vienna which produces blue-eyed whites, En which gives the broken pattern in Holland Lops and Du which gives the Dutch color pattern.
Every rabbit has two genes for each of the gene sets. When rabbits are bred the sire will pass on one of the two genes from the gene set, and the dam will pass on one gene from the gene set, giving the offspring two genes for each gene set. For example in the Agouti gene set there are three possible genes A, at, and a. The dam and the sire will each possess two genes from the set, and can be in any combination (A & A, A & at, A & a, at & at, at & a or aa). Lets assume that the sire has the gene set Aa, and the dam has the gene set ata. The sire will pass to the offspring either an A or an a, and the dam will pass on either an at or an a. The resulting offspring would have the following possible gene sets: Aat, Aa, ata, or aa. Often this is expressed in table format:
Each gene set has a particular order of dominance. In the gene set the most dominant gene will always be the trait that appears in the rabbit, and the other trait will be masked or recessive. The order of dominance in the Agouti gene set is A, then at, and last a. Well explain the agouti gene set in a minute, but if a rabbit possesses the A gene that pattern will be the one that show in the animal since it is the most dominant gene, regardless if their gene set is AA, Aat, or Aa. The only way an at can show is if the second gene is an at or an a (atat, ata), and the only way the a gene can show is if both genes or a (aa). If you are not thoroughly confused yet, then we are in good shape.
The Agouti gene set has three possible genes. They are list in order of dominance: A, at and a. The A gene is the typical wild rabbit color pattern. Rabbits with this gene would have white bellies, white eye circles and white on the underside of the tail. The individual hairs on a rabbit possessing the A gene will have color bands. If you blow on the back of the rabbit you will see circular bands of color, this is a result of this gene.
The at gene is known as the tan pattern. In order for this gene to display in the rabbit the second gene must either be an at or and a.If the second gene is an A (Agouti) the rabbit will carry the at but will show the A (agouti) since the A (Agouti) is dominant. The tan (at) gene has the same overall pattern as an Agouti. The belly will be white, the rabbit will have white eye circle, and the under side of the tail will be white. However, the individual hairs will not have color bands, but will be all one color.
The a gene is known as the self gene. Since this is the most recessive gene, the rabbit must have two as in the gene set to show this pattern (aa). With this gene the rabbit will be one color throughout their body, and the individual hairs will be one color.
There are only two genes in this gene set, B (black) which is dominant and b (chocolate) which is recessive. Colors in the B (black) set include black, blue, tort, sable point, and chinchilla. Colors in the b (chocolate) set include chocolate, lilac and lynx.
Because there are two genes in this set, there are three possible gene combinations: BB, Bb and bb. BB & Bb will both show the black. The only way for the chocolate to appear in the bunny is if this gene set is bb.
If you are breeding to obtain one of the chocolate colors, it is best to use a chocolate color rabbit. Its not impossible to get a chocolate from a black rabbit since both parents could carry the chocolate gene, but its a whole lot easier when starting with a chocolate.
This is one of the more complex gene sets. Not only does this set have dominant and recessive genes, but it also has genes with co-dominance and slight dominance, and even one gene that is affected by temperature. There are five different genes in this set: C, cchd, cchl, ch and c.
This series of genes will determine how full the color is in you rabbit. The most dominant gene in the set is the C, which will have your rabbit showing full color. On the opposite end of the spectrum the c gene will show a complete loss of color, or an albino. The c gene produces a REW or ruby eyed white, not a BEW or blue eyed white. There is another gene (v-vienna) that produces a blue eyed white.
The cchd and cchl genes have co-dominance. The cchd is known as the chinchilla gene, or chinchilla dark. The chinchilla gene will allow the production of some but not all of the color pigment in your rabbit. If your rabbit is an agouti, white bands will appear between the dark color bands. Usually its the yellow pigment that is reduced to white. This gene will also affect eye color and can produce rabbits with blue eyes.
The cchl is known as the sable gene, or chinchilla light. This gene is different than other genes, as it has what is called incomplete dominance. When you have a pair of sable genes cchl cchl the resulting color is not sable but rather a dark sepia color called seal. Seal is an almost black color. Like the cchd , this gene removes yellow from the hair shaft, and some darker pigmentation, leaving the rabbit with a shaded look. Unlike the chinchilla dark gene, this gene will leave the eye color dark.
The ch gene is known as the himi gene. Rabbits showing this gene are called pointed white, as the rabbit will be white except in the muzzle, ears, and feet. This gene is also temperature sensitive, and in colder temperatures, the color can actually be turned back on. This is why pointed rabbits will show color better in winter months.
The c gene is known as the albino gene. It will eliminate the display of color in your rabbit. Because of its properties, this gene will effect every other gene set as well, as it will wash out what ever the A, B, D, & E genes specify. The only way for this gene to be expressed in your rabbit is if the rabbit has two c genes (cc).
There are only two genes in this set D, which is full strength of color, and d, which is diluted color. Since the D gene is dominant if the gene set is DD or Dd the rabbit will show full strength of color. The only way to have diluted color is if both genes in the set are d (dd).
The dilute will weaken the color in full color rabbits. For example, Black dilutes to blue, and brown dilutes to lilac. This gene will affect eye color as well.
This gene determines if the color is extended all the way to the end of the hair shaft, or if the color stops at some point on the hair shaft and another color finishes. The non-extended hair shaft will produce colors such as black tortoiseshell. The rabbit will appear shaded as shorter hairs near the belly, feet in muzzle arent long enough to show the color change in the hair shaft, where longer hairs will show the change. This gene can easily be confused with the C gene set as it will all produce shaded rabbits, but for a different reason.
There are actually four genes in this gene set E full extension of color, ES extension of dark color, e extension of light color, and ej. The ES gene produces various steel colors, and the ej gene produces harlequin color patterns.
There are two genes in this color group En and en, with En being dominant. Enen will cause normal spotting as in a broken color Holland lop. EnEn will cause the rabbit to have spotting primarily on the head only. The resulting color is known as a Charlie. The gene set enen will result in a normally colored rabbit. Its generally not a good practice to breed to broken rabbits together as the results will be some charlies. However, if you are willing to wait for a second generation, the resulting charlies could be bred with a solid colored rabbit, resulting in brokens and solids.