Broken pattern genetics

[eco2pia]

I was wondering why my very lightly patterned mutt buck bred to my solid doe gave mostly solid kits with just two with white on their heads/front paws. I have found this one web site that makes it a little clearer.

http://rexrabbit.tripod.com/brokengene.html

I think that given his medium-small size it is possible my mutt has dutch in him somewhere, but also I found the discussion of modifiers interesting, and I am nearly beside myself to try my lightly patterned NZ on her and see what I get.

Also, I am hoping that line breeding back to my broken NZ buck may increase the modifiers in the line, resulting in more lightly-patterned kits. Is this a viable way of increasing modifiers? Can a solid rabbit carry modifiers for pattern that are not expressed? Or would I have to line breed him to a broken doe? Anybody know?

 

[Jack]

read this thread, some of the best genetics sites I have found so far
another-color-question-t2088.html

 

[eco2pia]

http://www.debmark.com/rabbits/genetics.htm

This one is particularly good, and I had seen it before but missed this passage:

"The basic color genes in the rabbit are A through E, En, Du, Si, V, and W. Other genes act as color modifiers controlling the intensity of certain colors or patterns. They include the rufus modifiers, the plus/minus (blanket/spot) modifiers, and the color intensifiers. These modifiers are not single genes, but multiple ones that pool their effects."

OK, I understand the rufus modifiers as well as the current science can tell us--there are some theories that different modifiers occur on different loci and no matter how many times you were to line breed, if the modifier isn't in the pool you could only intensify the red to a certain point. However that is a theory and not what I am working on--I have fairly nice red color.

I really wanted to know more about influencing pattern placement, I am aiming for an English Spot-like pattern rather than a blanket, and since my buck has the pattern I want, I think the genetics must be there...somewhere.

 

[Jack]

the spots seem, from what I have read to operate on +/- modifiers like the rufus red, with a white at the ---- end and a solid on the ++++

 

[eco2pia]

here is an interesting thread on another forum: http://s13.invisionfree.com/RabbitHabbi ... t28956.htm

In it someone is asking almost the same question (except their babies are too light) and they get this answer:

"Although your broken was heavily marked, it is postulated (and this I agree with) that the solids still carry those modifiers, you just can't see it as they don't have the broken gene. So your solid is probably very "minus" for the broken pattern, hence why all the babies are so light despite the heavily marked broken used. "

So my solid is probably very "plus"...and I should get more minus modifiers in solid daughters by a broken buck--except I wont know which solid daughters have the most minus modifiers! I am going to enjoy this, I love genetics...leave it to me to pick broken reds, one of the more complicated colors to achieve.

 

[akane]

Modifying a pied coat on any animal down to a certain pattern is a very big feat. It takes many many many generations of breeding with usually a lot of line breeding to narrow down the modifiers. Throw in one animal out of that gene pool and you can get randomness again. If you want a certain pattern I would look for brokens that display at least close to that pattern and avoid solids. Solids carry who knows what and will make it a lot harder to breed for something specific.

 

[eco2pia]

Akane, I hear you, but I have a broken buck and a solid doe and room for one more doe--micro operation! I want to have solids and brokens, but I am really just feeding my family. Originally my plan was just to have some variety in the nestbox for fun.

If I were to line breed broken bucks to solid does, would the odds of increasing the solid daughter's modifiers go up through the generations? What I mean is, do the modifiers still exsist, unexpressed under the solid coat, like the way black color genetics can exsist, unexpressed under a REW's double recessive cc? Or does the solid coat always indicate no modifiers? I realize the only way to figure out what a solid carries in terms of modifiers would be a test cross, but I am ok with that plan. In fact, since I eat the mistakes, I love that plan!

Is there any reason that a solid from a broken would be less desirable? Increased chance of DQ's like white toenails or something? Not that I am showing or plan to, really just curious. If I got one nicely marked buck a generation, that would keep me in business... I could cycle through several doe replacements in a buck generation.

 

[Jack]

The problem is that you have to keep a line of solids to breed the brokens to, as you have EN for normal, en for broken

BUT enen, the recessive, is a charlie, but breed your charlie to a solid and you get a litter of properly marked brokens
ENen

 

[akane]

You will always get some regular brokens from broken x broken. These are what you keep and what should be increasingly showing the markings you want with each generation. The charlies go (if you are in to meat rabbits that's easily solved) and for now the solid offspring as well. Eventually you could keep some solids because once the brokens become predictable you'd know what their solid offspring was carrying.

This cannot be done with just a trio or so of rabbits. You would have to keep several from each generation, breed them back to the parents, keep the ones that show the markings you want, and then butcher or sell everything else except maybe one or 2 of the original stock that already display the pattern you want and breed from there. If your breeding plan is going how you want it then you will be replacing older stock with the improved offspring every generation or 2. I would think once you get going you'd have 10-20 rabbits on hand at any time to make any sort of progress. With a very small number I'd forget about it and just enjoy what broken patterns you do get. The genetic pool is way too small and you will just be breeding back in the modifiers you don't want instead of eliminating them.

 

[Jack]

--------------
| EN | en | Solid, charlie = all broken
| EN | en |
--------------

en en Broken, broken = 25% charlie, 50% broken, 25% solid
EN EN

 

[eco2pia]

Thanks for the explanation Akane, just what I wanted to know...I may just keep back a broken doe based on that...for fun if nothing else. I realize that I haven't got a chance to get far. But it would be fun to try, and the freezer is their ultimate home, so no big deal. Plus, meat type trumps pattern in this barn. It will still be fun to see what happens. I understand that it won't really be a viable line.

Jack, I know a charlie and a solid makes a broken, but it doesn't guarantee showable pattern placement any more than a solid and a broken, because whether you get polka dots, or a blanket, or a raggedy blaze and a few white toes, is controlled by modifiers....and I wanted to know if the modifiers were passed independently of the En gene...In other words, does a solid carry modifiers? Akane has cleared that right up for me, and given me a heap more to consider also.

 

[Jack]

Hmmm, but you are only going to show them in the broken, My wife breeds broken polish, and she has good middle pattern, and has never had problems with her stock, so truthfully IDK. Most of hers are from one group (different lines, but not far removed) and reputable breeders, so it may be that I never know.

 

[eco2pia]

Actually I am not going to be showing them at all in any likelyhood. If I did show, I could probably show solids more readily around here, as 4-H meat-pen babies or something. The shows around here for NZ are pretty limited. Now if I wanted to show MR or ND or mini-lops...But very few seem to show the bigger rabbits. And I hate showing, but I just happen to be facinated by genetics.

 

[Jack]

OOH, experiment and LUNCH
hmm, tasty genetics, hell I'm vegetarian and I'm still up for that.