Topic: color genetics
I am always entertained by color genetics. I used to be consumed by predicting what color bunnies would be born if I paired certain rabbits. I learned a LOT by going after RED rabbits with French and English angoras for 8 years. [The red factor has been put on a back burner while I go after HEALTH in German crosses (not as easy as I hoped)].
At any rate, it struck me last night that Sydney and Neo have created an interesting litter.
Sydney is chocolate (and I while don't have a picture of her at the ready, here is an English angora I had years ago to show the color):

Neo is tortoiseshell:

and from their gene sharing, we got
4 black rabbits and 4 white rabbits:
This is a colorful business!
So here's how it works:
The dominant genes are ABCDE.
The recessive genes are abcde.
There are few moderately dominant and modifying genes, but in this case they do not come into play.
A complete discussion of how color shows itself in a black rabbit is here on the blog:
BareHare January 2004
Neo is aaB-CcD-ee.
Sydney is aabbCcD-E-.
I know what these parents are genetically because:
1. I have bred them before and seen what color bunnies they had. Neo has never had a chocolate bunny, but both his grandmothers were chocolate.
2. I have bred them before and know there are UNDERLYING genes in the "D" and "E" positions...therefore the white bunnies posses wild cards in that department!
In fact, I was SURE Neo had a chocolate gene. And he may have. That does not mean it will come out in any litter, even though the odds were fabulous that IF he had a chocolate gene, it would pair with Sydneys' and produce some chocolate bunnies.
They had black bunnies that are:
aaBbC-D-Ee
And white bunnies that are:
aab-cc--e-
Recessives can cruise along undetected for generations and then express themselves one fine day. But the nice thing about Sydneys' bunnies is that I KNOW each white and black bunny has a recessive "b" chocolate gene from Sydney, a recessive "a" self color gene from either parent, and a recessive "e" gene from Neo. The NEXT generation from this litter will produce those recessive expressions IF I pick the right parent.
Want to read more?
Links for color genetics in angora rabbits:
Island Gems
Kanien