*New to Genetics? Don’t let this page confuse you till you’ve checked out our Simple Rabbit Genetics Primer and Part 1 of the A-series discussion*
Rabbit Breeding Outcomes With Respect To the A Gene
Now we get to the fun part: what happens when you breed one rabbit to another, with respect to the “a” gene. Knowing what two rabbits’ genotypes are (or even just their phenotypes, in some cases) can tell you what the possibilities are for their offspring. Likewise, looking at offspring (and determining as much of their genotype as possible) can tell you about the unexpressed, or recessive genes, of the parents.
Since it does not matter which parent has which set of a genes, there are 21 possible combinations of A/at/a genes in parent rabbits (there are 36 combinations, but 15 of them are duplicates; that is, an “at-a” father to an “a-a” mother has the same outcome as an “a-a” father to an “at-a” mother). Fifteen of those combinations involve the agouti gene. If you have no agouti animals in your barn, your “A/at/a” gene possibilities are much more limited. Likewise, 14 of the combinations involve the “at” gene. If you do not have the “at” gene in your barn, you will have fewer possibilities to consider. If you have only self rabbits, you’ll never get anything but self rabbits.
Let’s just pick one combination as an example to look at so that we can understand the possible outcomes in the offspring. Suppose you breed an agouti Netherland Dwarf (let’s just say a chestnut) who carries the self gene with an otter who carries the self gene. The chestnut is “A-a” while the blue otter is “at-a,” in this case (other times a chestnut may be “A-A” or “A-at” and the blue otter could have been “at-at”). You can see that, on the average, 50% of the offspring will be agouti rabbits, 25% will be selfs and 25% will be otters or martens (depending on the C gene).
A-a x at-a |
Blue Otter | ||
| at Gene | a Gene | ||
| Chestnut | A Gene | A-at Agouti carrying otter/marten |
A-a Agouti carrying self |
| a Gene | at-a Otter/Marten carrying self |
a-a Self |
|
Let’s now look at what happens when you breed an otter that carries the self gene with another otter that carries the self gene. On the average, out of every four babies, you could expect three to be otters and one to be a self. Two of those otters would carry the self gene while one of them would be a true-breeding otter.
at-a x at-a |
Black Otter | ||
| at Gene | a Gene | ||
| Black Otter | at Gene | at-at True Breeding Otter |
at-a Otter/Marten Carrying Self |
| a Gene | at-a Otter/Marten Carrying Self |
a-a Self |
|
Please note that the self rabbits produced from two such otter parents do not carry the “at” gene. Self colored rabbits (black tortoiseshell, blue tortoiseshell, black, blue, chocolate, lilac, etc.) cannot carry either the otter gene or the agouti gene. If a rabbit has the agouti gene, it will be expressed. If a rabbit carries the otter gene, the self gene will be hidden under it (not vice versa). Thus, a black rabbit cannot “carry” the otter gene.
Since there are so many combinations of “A/at/a” genes when breeding rabbits, I won’t attempt to make a complete table for each one. But below you will see the possible combinations and the expected outcomes for each. (Remember, these are averages–your exact results will vary, except when the percentage is 100, of course.)
| A-A | A-at | A-a | at-at | at-a | a-a | |
| A-A | 100 % A-A |
|||||
| A-at | 50% A-A 50% A-at |
25% A-A 50% A-at 25% at-at |
||||
| A-a | 50% A-A 50% A-a |
25% A-A 25% A-at 25% A-a 25% at-a |
25% A-A 50% A-a 25% a-a |
|||
| at-at | 100% A-at |
50% A-at 50% at-at |
50% A-at 50% at-a |
100% at-at |
||
| at-a | 50% A-at 50 % A-a |
25% A-at 25% A-a 25% at-at 25% at-a |
25% A-at 25% A-a 25% at-a 25% a-a |
50% at-at 50% at-a |
25% at-at 50% at-a 25% a-a |
|
| a-a | 100% A-a |
50% A-a 50% at-a |
50% A-a 50% a-a |
100% at-a |
50% at-a 50% a-a |
100% a-a |
Although the different breeds allow different colors to be shown, the genetics are the same all across the board: from Mini Rex to Fuzzy Lops to Netherland Dwarfs to Satins… everything with ears upright or floppy!
Don’t miss the next article in this series — So what does this mean to my breeding program?
