Eye color gives clues to underlying genetics. I thought I pretty much knew the genetics of the parents here: above is Neo, a tortoiseshell Dad with clear brown eyes; whose genotype I am pretty sure is:
aaBBCcD-ee
and Sydney, a chocolate doe with brownish eyes, pictured below, whose genotype is
aabbCcD-E-:

But wait! They had a litter that came out in surprise format!
4 of the bunnies were white, which is fine:
aaBbcc---e, and 4 of the bunnies were black, which is also fine:
aaBbC-D-Ee. So far, so good. But, as they reached 5 weeks of age all of a sudden I got a clear look at the eye color of the black bunnies:

Fully black bunnies have brown eyes, and the fellow in the front has grey eyes. Grey eyes in a black rabbit can be caused by having an incompletely dominant "C" gene allowing only SOME of the black and yellow pigments possible in a rabbit express themselves.
(To read all about the black and yellow pigments in any given rabbit's genetics, check out this older post)
So, now we are looking at a "chmc" expressing or a "chdc" expression. Which parent is the culprit?

To get ANY white bunnies in a litter BOTH parents have to have a little "c" gene, which leaves them ONLY one spot to have a big "C" gene. So, one of them has eyes that are not as dark brown as they could be. Mama is the culprit, I can assume. She is the ONLY chocolate rabbit in the barn, and I have had no one else to compare her eyes to. Since her coat has stayed pretty dark, I will rule out the chl gene (although I am open to reinterpretation if someone can suggest further information about this!). That leaves chd and chm as possibilities.

The info I have gathered to date tells me that chm will allow light brown eyes and dark fur. Hmmm. Chm is one of those in-between "C" genes that some color genetics texts discount, preferring to use either a chd, or chl in its place.

So, I am still in a quandry, but I have a little more respect for genes that can modify a color's full expression!

Posted by countrywool at 1:21 PM EDT

Updated: Thursday, 23 June 2005 1:23 PM EDT

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The Massachusetts Sheep and Wool Festival is this weekend, and I will spend Saturday morning there browsing, shopping and picking up two new bunnies. I have long wanted a German rabbit from Nancy Benda at The Spinning Bunny, and made connections to finally get one this spring! And Charlene Schultz has another black buck bunny for me that is related to my beloved and lost Zwart, so I will bring him back, too. It seems like 2005 is my year of LOTS of rabbits, for I have 15 bunnies on the ground; a last litter due tomorrow; and the two I have purchased. The barns will be empty no more!

So, a question about the red glow in brown eyes has surfaced. Can it mean that the color red is underneath???? Sadly, no. I had the same question back in the beginning as I was hunting for red signs in my adult stock, so I had an idea who to breed to get red bunnies. The red glow generally means there are modifying "C_c" genes letting only parts of black and yellow color shine through the coat and eyes. Sometimes I wonder if the "D_d" genes put a damper on the full expression of whatever color is in the "B_b" spot. I have not had any full "shaded" rabbits here, but I am told they, too have a red glow to their eyes in the right light. Also, chocolates (and blues I would suspect, but I don't have any!) have a red glow to their eyes in the right light. I have even had chocolate rabbits who have golden tips on their fur around their heads. The golden fur is sunburn (!).

A complete discussion of the "C_c" gene and what it does to eye color is found in an older post here

Red comes from Rufus modifiers ADDED TO a tortoiseshell or fawn pattern
A-B-C-D-ee
aaB-C-D-ee
A-bbC-D-ee
aabbC-D-ee
They are only expressed when the "no B or b showing" rule (ee) lets them shine. Rufus can be shown in degrees, and it is denoted as "+". There are five degrees in a full red rabbit, and breeding a +++ to a ++ you CAN get a +++++.
Rufus modifiers are unmistakable in a red parent, and as far as I can tell, totally masked in other colors although they can be carried along from generation to generation.

Red is always a wild card when you breed for "ee". It's always Christmas morning when I discover it in my rabbits!

Posted by countrywool at 7:43 AM EDT

Updated: Thursday, 26 May 2005 7:47 AM EDT

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Grindle was born here in early December, making her 12 weeks old now. The day today is sunny and above freezing, so she and I spent some time together out in the sunshine taking pictures and just hanging out. She is a lovely rabbit. It always amazes me how the personality of an animal exhibits itself so soon after weaning and living on their own.

Her eyes are brown, but she has a softer center golden ring around her iris. Her grandmother Matilda had very light brown, almost gold eyes, and I suspect the chm or chl gene was the most dominant "c" gene she owned and passed down to her offspring.

Her coat also exhibits clear "rings" of black and grey under color at the ripe age of 12 weeks:

It almost appears silvery underneath next to her half sister Liesl (who will pay a visit to this blog tomorrow), but on the surface both are identical in color. In my continuing quest to identify a solid black color, I continue to note differences...and Liesl's eyes are darker brown than Grindle's.

Posted by countrywool at 12:49 PM EST

Updated: Sunday, 29 February 2004 5:18 AM EST

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Eye color is dependent on a couple of genetic factors. Above we see Liesel, the doe in Liebchen's litter that is staying at Countrywool for breeding evaluation. Liesel is 5 1/2 weeks old, and her black coat and clearly dark brown eyes tell me her genetics color makeup most likely is:

"aa" Self or solid color. The color on each fiber shaft is black. Darker at the tips and fading paler to charcoal at the base. At this point her color is very dark for her fiber is short. As it grows, things will happen and her coat will fade as the intermediate fiber shaft grows long very fast and does not retain the depth of the colored tips of her coat, which will always be black. Her face, where fur remains short during her life, will always be black. I am journeying on a discovery mission to find out if stray white hairs identified on the face of a "solid" black rabbit will lead to white hairs in the coat at a later age. Stay tuned. I will have more info in ten years.

"B-" Black, which is the dominant gene for color in the gene pool. The "-" could be either "B" or "b", but it makes no difference what it is for "B" always shows itself regardless of the attributes of its companion gene. It may indeed be "b", since Liesel has a chocolate brother, and we may be able to determine this after she is bred. Interestingly enough, now I know that Liesel's black mother Liebchen carries a hidden "b" gene in HER makeup. A true black self/solid colored rabbit will have brown eyes IF the "C" genes allow for it.

"C-" All color provided by the "B" genes shows through fully. Well, this is true now, and will be true later, but there are questions in my mind about those silly white hairs in an adult coat. When color shows through fully, then eyes will be brown. There are a number of "c" genes that alter the color expressed making the coat more yellow or less black, and adding a few new tones to the gradations of color from black, blue, chocolate, lilac of the coat. These genes also change eye color, and they work cooperatively when the right combos are present, so you can get light brown eyes, golden eyes, marbled brown eyes, grey eyes, and marbled grey eyes. They are:
"chd", "chm", "chl", and "ch"
I suspect one of these may be in Liesel's background, but they are not expressed right now. They may not ever be expressed, as current genetics understanding goes, but I have my doubts. Stay tuned.

"D-" Color depth expression is as deep as it can be, while allowing for the other genes to make a play on which color gets expressed. Currently the accepted genetic expression of "D" is black, and "d" as the dilute of black, or blue. When "D" is present, eye color is as dark as it can be, So, brown.

"E-" The extension gene. This factor will keep color expression confined to PARTS of the body, or allow it all over. "E" allows it all over, so Liesel, being an all-over colored black rabbit has this makeup. If her makeup was "ee" she could still have brown eyes, as "ee" confines full color to the head (eyes!) and ears, back haunch, tail, and feet, and strips out any black/blue/chocolate/lilac from other parts of the coat, leaving a cream/golden bunny with solid colored extremities. There are a number of additional "E" genes that have been wrecking havoc with my herd "Es" and "Ej". I suspect "Es" is at work. The steel gene expresses itself in partial spurts here and there when the genetics are not quite perfect for full expression, and that may be the reason I am seeing stray white hairs in the coats of my black rabbits. Stay tuned.

Posted by countrywool at 10:50 AM EST

Updated: Wednesday, 14 January 2004 10:57 AM EST

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