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SilverStar Polish Rabbitry

An Attempt at Explianing Color Genetics and Compatabillity in the Polish Rabbit.

This article is writen for polish, but the genetics apply to other breeds too.  CLICK HERE for an article on Silver rabbit color genetics.

Part I- Black, Blue, Chocolate, and Lilac

I realize that probably many of my know what you get when you breed certain colors together. You may have your own guidelines or ways of doing things. You may know that breeding a black to a chocolate will give you black--unless the black carries chocolate. But if you bred two blacks and got a lilac, would you know why? So, when breeding certain colors to certain colors in Polish, what will you get?

Black: The most dominant color in Polish is black. (well, actually broken black, but that's another deal altogether.) We sometimes say, "All I ever get is black!" It can sure seem like that at times! Breeding black to chocolate, blue, lilac, or REW will give you black, 100%, every time... UNLESS your black carries another color's gene.

There are 5 basic color gene series in rabbits. They are easy to remember: A, B, C, D, and E. Within each series there are dominant and recessive genes, indicated by the case the letter is in, or a superscripted letter after it. (like B is dominant, b is recessive. C is most dominant, followed by cchd, cchl, ch, and c..) Some series have several genes, such as C; some like B just have two. The only two gene series that we will be dealing with today are B and D, and both only have two genes, dominant and recessive, B and b, and D and d. When breeding only black, blue, and chocolate, avoiding brokens and whites, the only gene series that we use for polish are B and D.

B is the chocolate gene. It is recessive, hense breeding black to choc = black. B is the symbol for dominant black (or blue!) b is the symbol for recessive chocolate (or lilac!). A black can carry chocolate. So its genotype would be Bb. A black that didn't carry chocolate would be BB. Chocolate however can't "carry" black, it doesnt need to to throw black. (chocolate's genotype is bb.) Breeding a BB (black/doesn't carry choc) to a bb (choc) will give you entirely Bb-- black carrying chocolate. The offspring get one "letter" from each parent. The black can only give a B, and the choc can only give a b. Now lets say that the black did carry chocolate, and you bred it to a choc. (Bb x bb) You would get both black and chocolate. (maybe not every single time you bred the pair, but eventually, and supposedly 50% of the offspring should be each color.) The choc can only give a b. In cases where the black gives a B, you get Bb--black carrying choc. In cases where the black gives a b, you get bb-- choc. Follow me?

The blue gene works just the same way, only with the D series. The D is non-dilute, like black or chocolate. The d is dilute, like blue or lilac. The only color of the four we are working with that is dominant each time is black; the only color that is recessive both times is lilac.

Black: B_ D_

Lilac: bb dd

Blue: B_ dd

Chocolate: bb D_

The blank symbols ( _ ) are in case of a dominant gene where you don't know what it carries. For example, take chcocolate. You know that it has to be bb D_ . You don't know just by looking at it if it carries blue/dilute (Dd) or not (DD). A black could be Bb Dd, BBDd, Bb DD, or Bb Dd, you'd need a pedigree and/or breeding records to find out. Where it is not known, you put a blank. (Note: blue and chocolate are interchangable for the most part in the examples in this article. Anywhere i use chocolate as an example, blue could be substituted, as long as you also change the appropriate gene symbols.)

So... Black: Breeding black to anything, (black, blue, choco, lilac) will give you black, we covered that. this applies for brokens too. Broken black x blue = black or broken black, ignore the broken gene for the present, we're talking about the color of the broken. we'll get to brokens later. Two blacks can throw a chocolate if they both carry chocolate . Two blacks can even throw a lilac, if they both carry BOTH blue AND chocolate. Breeding a black that carries choc only to a black that carries blue only ( Bb DD x BB Dd) will give you 100% blacks, some carrying choc (Bb DD), some carrying blue (BB Dd) some carrying neither (BB DD) and some carrying both (Bb Dd) It all depends on what each parent happens to give.

Blue: Blue is dilute dd, and non-chocolate so B_. Blue can carry chcolate. (Bb dd) or not (BB dd). -Blue x black= Black, or blue if black carries blue. Choc and lilac are possible if both carry chocolate as well. - blue x blue = all blue, never a black, never a chcocolate. (dd x dd = dd ALWAYS. 2 recessives cannot throw a dominant!) Blue to blue can throw a lilac if both blues carry chocolate. STOP! Before i confuse you further, we're going to skip ahead to lilac now. If you can understand black and lilac, you get blue and chocolate with the package.

Lilac: Yes, lilac is not currently a recognized or showable color in polish. However, when working with blues and chocolates, the genes are there to create lilac. Lilac can be thought of as both blue AND chocolate combined. It is a recessive chocolate color (bb) and it is recessive dilute (dd). So how do you get a lilac? You've likley been told at some point "breed blue to chocolate and you'll get lilac" even if you know that this isn't strictly true. You could breed a blue to a choc every day for five years and NEVER get anything but the ever-present black. Stop and think about this genetically. What is chocolate? bb D_ (we'll say for this purpose its bb DD). What is blue? B_ dd. (for this example, it will be BB dd). You breed the two together and... the blue provides the B_ and the choc provides the D_. So you get Bb Dd--black carrying blue and choc. The blue in this case can only give a B and only a d. the choc can only give a b and only a D. Breeding two of those offspring together (Bb Dd) can result in blue, lilac, chocolate, and black. Lilac can also be achieved by breeding two blues that carry choc, or two chocs that carry blue. Or a black that carries both to a choc that carries blue, etc, any two rabbits that express or carry both blue and chocolate. So there you have your blue and chocolate color compatabillities as well. A blue to blue or choc to choc will ALWAYS throw blue or choc, respectively, as long as both parents don't carry any hidden recessive genes. If they do, lilac is possible. But both parents need to carry the recessive blue gene (for chocs) or choc gene (for blues.) In the same way, if you breed black to black, both have to carry blue to throw blue. Just one carrying it isnt enough. (DD x Dd = 50% DD and 50% Dd, but all black.) The recessive genes can be passed down indefinitely. For instance, a black doesnt need to have chocolate in its visable pedigree (just 3 or 4 generations!) to carry a choc. but always down the line some rabbit hid the chocolate gene and it got passed down to this rabbit. I have gotten a chocolate from a blue when bred to a black. The black was out of a chocolate so it HAD to carry chocolate, but the blue didn't have any chocolate behind her that i could see. Still, one of her parents was Bb, and one of its parents was Bb, and so on, each passing down that hidden recessive b to the next generation. Any of those rabbits could have thrown a choc.

ON A SLIGHTLY DIFFERENT TOPIC...(ok here's where you can't interchange blue and chocolate anymore) So we have what colors you will get when working with black, blue, chocolate, and lilac, but now let's touch on the quality of those colors.

Scattered white hairs: Scattered whites are a fairly common trait in all four of the colors. These are a hereditary fault, and you are better off without them in your herd (speaking show-wise). A still common myth is that breeding broken into your solids will result in solids having scattered whites. This is incorrect. Scattered white hairs have nothing to do with the broken gene. Some brokens will have scattered whites too, if you look. Its especially evident in the ears on brokens. These can pass down scattered whites to broken AND SOLID offspring, as solids can pass scattered whites to broken offspring. REWs are also said to pass on scattered whites and white toenails. this is only because the REW hides these things, since the whole rabbit is white.

Chocolate to chocolate: It is said that choc should not be bred to choc for more than three generations, without crossing in black to intensify the chocolate color. Choc to choc for too long will result in a washed out color. I have not had any real personal experiences to back this up either way. However, the rabbit that i have that has the best chocolate color is out of a chocolate and a black that has no choc in the visable pedigree.

Dilute to dilute: White nais are a disqualification,and can occur in all colors of polish, but most commonly in the dilute varieties (blue and lilac). However crossing dilute to dilute will not necessarily result in white nails. White nails are most commonly just caused by modifiers but can also be caused by the BEW (not REW!) gene.

Ok, that's enough for today! In part II we will discuss REW, the A series, and the E series.

Part II-- REW, A, C, and E.

 

Remember that there are five basic color gene series in rabbits, ABCD and E.  B and D are the two simplest by far, as well as the two that we use the most in Polish. 

 

THE C SERIES has not just two genes in it, a recessive and a dominant like B or D, but five.  Each gene down the list is dominant over the ones below it, can carry the ones below it, but is recessive to and cannot carry the ones above it.

 

C is the most dominant, called "full color".  These are our blacks, blues, and chocolates, no shading.  Colors like chestnut, gold-tipped steel, orange/red, opal, lynx, otter and tort, etc, are C_.

 

chd is the next most dominant. (This is supposed to be written with the hd superscripted, like this: chd  however when typing most people do not superscript the hd, hl, h, or whatever it may be in the case of that gene.) It is recessive under C, can be masked/carried by C, but masks everything below it.  This is chinchilla dark, or what we would just know as chinchilla.  There are no recognized polish colors expressing chd, and to my knowledge there are not any polish that carry or express this gene.  Colors like chinchilla, squirrel, silver-tipped black steel, and silver marten are chd colors in other breeds.

 

chl is called chinchilla light, but has nothing to do with what we think of as chinchilla.  It is actually the shaded gene.  Sables, smoke pearls, sable points, sable marten, and seal are all chl colors.  I have heard of sable and smoke pearl polish cropping up, and in this case the parents would have been Cchl to Cc (or Cch).  (If both were Cchl x Cchl you would get seal...but that's too confusing for right now, just cull them all instead! LOL).  Obviously, smoke pearl and siamese sable are not recognized polish colors.  A sable is the same as a black, only shaded.  Where a black is aa B_ C_ D_ E_ a sable/siamese sable is aa B_ chl_ D_ E_.  Smoke pearl is the dilute of sable as blue is a dilute of black.  A tortoise is not shaded, though it may look it, but is a full color C. 

 

ch is himalayan, californian, pointed white.  ch is dominant only over c.  There is a himalayan polish owned by someone who will be reading this!  I've seen her, she looks like a very nice typed polish! Its not the breeder's fault, but for generation upon generation the recessive ch gene got passed down hidden under C (Cch) until two rabbits like that were bred together....and BAM!

 

c , lastly, is REW.  We do use c when breeding polish.  A cc is a REW.  A cC is not a REW, obviously because that is not possible, c cannot carry anything, as you know.  Cc is a black, choco, blue, etc carrying REW, but the color of the black, etc is not affected.  While c is recessive under the rest of the C genes, a cc is ALWAYS REW.  For illustration, a dd is not always blue.  It is always a blue/dilute COLOR, but it may be blue or smoke pearl or blue point, or broken seal squirrel (that is possible by the way)... you get the idea.  A cc is always REW, no matter what the other color genes the rabbit has.  A REW could be Aat BB cc Dd Esej or aa bb cc dd ee, it's still a REW.   Do not let REW be confused with BEW--they are way different.  

 

So we now (hopefully!) understand B/b, C/c, D/d.  Lucky for us with polish, we can generally disregard all C genes except C and c. 

 

Some examples for genetic codes of colors

 

-a blue out of a black and a REW is B_ Cc dd.  (remember that since it is out of a cc it has to carry c.)

 

- a black that throws lilac is Bb C_ Dd

 

- A black that carries nothing is BB CC DD

 

But what about A and E?

 

THE A SERIES...

 

A is agouti.  Chestnut, most steel, opal, frosty, but no polish colors, EXCEPT that several BEW are agouti underneath, thus breeding BEW to a black, blue, chocolate, or lilac can result in chestnut sports.  (AA (the agouti hidden by the BEW) to aa (self black) = Aa).  But more on agouti and BEW next time!

 

at is tan pattern.  I have never heard of a polish that expressed or carried tan pattern.  Tan patterns are tans, otters, and silver martens, etc.

 

a is our self polish.  Blacks, blues, chocolates, lilacs are a, self.  In polish, most REWs are a, but are not necessarily self. 

 

And THE E SERIES

 

When you get into the details of most E genes, they get the more confusing than any other.  Luckily we polish breeders should have nothing to do with it, excepting the E, full-extension, black blue chocolate lilac type gene.

 

Es is more dominant than E, but needs the A / Agouti  gene to express itself, or else it can look like an E…it’s weird, I don’t entirely understand steel, and hopefully we’ll never have to deal with it in polish!

 

E is our full-extension, black blue chocolate and lilacs…  Chestnut, opal, lynx,  chinchillas, otter, himalayan, siamese sable are all E.

 

ej is tri-colored or harlequin.  Again, it needs the agouti to look right. 

 

e is non-extension.  These are the “yellow” colors (and don’t need agouti.).  Tort, orange, red, fawn, cream, (not lynx!), and sable point are e colors.

 

Your average black polish is aa B_ CC (or Cc) D_ EE.  A blue is usually aa B_ CC (or Cc) dd EE.  For a list of what each color’s genotype is see this link:

http://amysrabbitranch.com/genotypes.htm

 

Remember to apply rules from the last article in working out what genes your rabbits carry and what you are likely to get when breeding a certain pair.  For an easier way to work this out, use punnet squares (The following paragraphs are part of an article by a friend of mine, Amy Scholten.  Amy helped me learn color genetics in the first place, and I have permission to use her article.  Amy’s website is http://amysrabbitranch.com )

 

Punnett Squares
    Punnett squares are used to determine the probable outcome of a cross. In English, they help to figure out what could happen when you breed two rabbits (or anything else). For example, if I have a chocolate doe that I want to breed with a black buck, what colors could I get? That's when punnett squares come in handy. The difference in black and chocolate colored rabbits is the 'b' gene. In this cross, they will both be homozygous, meaning that they have the same two genes (example: bb) Here's how it's set up:

(chocolate) bb x BB (black) -each rabbit can pass on 1 allele.
                  b or b x B or B

     |  B  |  B | 
 b  | Bb |  Bb|
 b  | Bb |  Bb|
  All the babies are heterozygous black. Heterozygous means that they have two different genes. Black is totally dominant, so they will all be black. They will all carry the chocolate gene. If I cross two heterozygous chocolates, one out of four will be chocolate. I'll set it up:

    Bb x Bb
B or b X B or b
     |  B  |   b  | 
  B | BB |  Bb |
  b | Bb |  bb |


     There is one homozygous black, two heterozygous black, and one homozygous chocolate. Keep in mind that there might be more chocolates, or no chocolates all together! Punnett squares only determine probability, not frequency. They can be done with as many genes as you want! Just 'cancel' out all the homozygous pairs that are the same, and do the cross with the rest!

chocolate: aa bb CC Dd EE    

black: aa BB CC Dd EE

All the a's, c's, and e's are the same, so cancel them.

The cross is: bbDd x BBDd   Figure out all the possible combinations, then do it!

     | BD    | BD     | Bd     |   Bd   | 
bD| BbDD |  BbDD | BbDd | BbDd|
bD| BbDD |  BbDD | BbDd | BbDd|
bd|  BbDd |  BbDd | Bbdd  | Bbdd |
bd|  BbDd |  BbDd | Bbdd  | Bbdd |
   

   75% are black, 25% are blue.

    A tip for doing punnett squares is to always write the dominant gene first in the square, and the recessive after it. Keep the genes in order though (ABCDE...). In this last cross, I didn't cancel the 'Dd'. That is because they aren't homozygous. If I would have canceled them out, then I wouldn't have realized that I could get blue rabbits.
    Punnett squares can get a whole lot more complicated. I tried a cross once for fun that I was only able to cancel one gene pair out! It took a very long time to do. Most of the time, the more diversity in the genes, the more possible colors. The problem with this is that the colors might not be recognized in the particular breed. That can be good or bad, depending on the goals of the breeder.

 

There you have it!

 

But hey!  What about broken?  And BEW?

 

NEXT TIME! : 

 

Part III:  BEW, broken, Du, Si, and W.

 

Part III. The other five

So... We've covered ABCDE, and still havent seen broken, or BEW. Well, there are five MORE gene series!!! These 5 are in a way simpler.

Up to this point, generally every gene we've covered will entirely cover the genes recessive to it, with one or two exceptions. For example, a black carrying a blue (Dd) will look no different than a DD, or a black that does not carry blue. The genes in the next 5 series do not quite operate this way.

The broken gene is written En, for English. The English Spot, Checkered Giant, and Rhinelander patterns are nothing more than brokens bred for certain markings. The first brokens were English Spots, hense the En gene.

A rabbit whose genotype is EnEn (two dominant, don't let the n confuse you), is a charlie, a white rabbit with a few markings. A rabbit with the genotype of two recessive enen is a solid. And then, a broken is Enen, one dominant and one recessive. This is why you get solids, brokens and charlies with a broken to broken cross. A EnEn (charlie) bred to an enen (solid) will throw entirely Enen...which is a broken with over 10% color. This is why using a charlie in your breeding program is different than using a rabbit with a disqualification or fault such as inherited malocclusion or pinched hindquarters.

The color of the broken is determined by the rabbit's ABCDE genotype. Since a REW masks all else, a REW can be a broken underneath the white.

A rabbit cannot "carry" broken.... I think if you get what i've been talking about you'll understand why.

BEW: Blue Eyed White is similar to En, but a little more complex. V is the symbol for the BEW gene, since the old name for BEW is Vienna White. Most rabbits are VV, non bews and non-carriers. A vv will always be BEW, in this way it works like cc REW. (if a rabbit is both cc and vv the REW will show.) So the BEW is often another color underneath, and for some odd reason in Polish this often seems to be chestnut agouti. Breeding a BEW vv to a non-BEW VV will result in 100% Vv BEW-carriers. These carriers will often be marked with white, somewhat resembling a dutch marked rabbit. But note that dutch is an entirely different gene than BEW. A rabbit such marked is called a BEW Sport or, as is becomming more common, "VM" for Vienna Marked. On a pedigree this would be written, for example, Black VM. Occasionally a Vv will not show any white, and will look and can be shown like any other rabbit of its color. Still, it does carry BEW and this should be noted on pedigrees so future breeders don't get scared when it throws a BEW or a VM. This would be written "Black VC"

Following the "rules" that i've outlined already, I'm sure that you can figure out that 2 BEWs will always throw BEWs (or rews...). VV to VV can never ever throw a Vv or a vv...you get the picture.

there are three more genes. none of these are used in polish.

Du- is dutch. Du is dominant non-dutch, du is dutch. A Dudu will be partially marked

Si- is silver, like in a silver or a silver fox breed. SiSi is non silvered, Sisi very lightly silvered, and sisi is silvered.

W affects red and tan rabbits.

We're nearly done! Coming next month...

Part IV... Modifiers, a few notes, and a summary!

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