Chinchilla Genetics--the basics of chinchilla mutation colors

Copyright 2008 by Lyn Sedwick Shuster, Lyn’s Chins, www.centralfloridachinchillas.com, Orlando, FL

A cute brother and sister, Dylan, a homobeige boy and Lyra, a light ebony girl--what colors were their parents? Answer at the end, and you’ll know by then without looking!

Any discussion of genetics involves a least a little bit of “basic science” but you can understand what’s going on with chinchilla colors pretty easily, or at least for MOST of the colors. Certain color genes are difficult to understand because they can be “additive” (ebony) or lethal in double doses (the TOV/velvet gene and the white gene), and some combination colors aren’t difficult to explain but sometimes difficult to appreciate in an animal (like “viophire”--violet and sapphire, and beige-sapphire and beige-violet combinations). But consider this: some animals have genes for short and long fur, or white bands around their middle or dappling in their coloration, and trying to understand all the possible genetic combinations with color and these other pattern and fur-length variables is truly mind-boggling for the serious breeder. We are lucky with chins: only a few colors, some dominant, some recessive. And although there is a long haired chin, an angora, they are rare and you are not likely to ever see one.
OK, back to genetics from high school, or college. Every animal has two copies of each chromosome, which are the large structures that are made up of many genes, the exception being the sex chromosomes in which case females have two X’s and males have one X and one Y. These are not important considerations for chin color genetics because no color genes are on the X or Y chromosome. Both parents contribute ONE copy of each of their chromosomes to the “gametes,” eggs for females and sperm for males, which combine to form the offspring. Which copy of each of his/her paired chromosomes the parent contributes to an offspring should be random.
Next subject: recessive versus dominant genes. We all have two copies of each gene (let‘s stop here: a gene is a section of DNA that codes for a protein (or proteins) that results in a single recognizable trait….like color of skin or eyes. Lots of inherited traits are “multi-genic“ and not a result of the expression of just one gene, but chin colors are felt to be secondary to single mutations/changes in genes that code for color of fur). If a gene is “dominant,” then it will be expressed even if there is only one copy of that gene present. Recessive genes need two copies to be expressed. In humans, brown eye color is dominant, blue is recessive, thus you could have one copy of the brown gene and end up with brown eyes. Conversely, two parents who have only one copy of the brown gene each, and the other “paired” gene with blue, can have one or more kids with blue eyes--remember: blue is a recessive gene so you need two copies to have the color expressed. Now, two parents with blue eyes can NEVER produce a child with brown eyes, except if there is some hanky panky and they are not the real parents OR if there is a mutation in the germ cell (egg or sperm) that “creates“ a new brown gene. And mutations do happen, they HAVE to happen, and they happened in chinchillas or we would not have different colored animals now--all the chinchillas that were brought down from the Andes Mountains in the early 20th century were standard grays. Every chinchilla in captivity descended from those chinchillas. Breeders over time occasionally would notice a kit of a different color and breed that kit often using inbreeding to try to come up with the color again.

STANDARD GRAY CHINCHILLA:

To get back to dominant versus recessive: in chins, beige, black velvet (TOV), and white are dominant color genes; violet and sapphire are recessive. Gray might be thought of as recessive too.
OK, let’s talk colors: gray acts like an allele to one color, and does not act like an allelle to others, meaning gray acts like it is the same gene as one color, other colors are in different locations from the gray gene and there are even some that can “alter” color. What is the gray allele? Beige, which is a dominant gene. Violet and sapphire are recessive, but located elsewhere, and we know this because you can produce an animal with beige and violet or beige and sapphire. And, violet and sapphire are not alleles presumably because you can produce a chin with both colors present (so-called viophire, although this is debated). What are the other colors that chins can have? Ebony, black velvet and white. How do they combine?
OK, let’s back up again. Dominant again means you only need one copy of the gene to “dominate” the color picture, so an animal that has, let’s say, one copy of gray and one copy of beige will be, guess what, beige! Now, the interesting thing in chins is that if an animal has no copies of gray and two copies of beige, he is also beige, but a much lighter color beige, and is called “homozygous beige” or homobeige for short, to indicate that the animal has two copies of the beige gene. Conversely, an animal with one copy of beige (and one of gray), is a “heterozygous beige” or heterobeige for short. All beige chins, homozygous, heterozygous or combined with any other genes like white/TOV/ebony, also have red/pink eyes. See the pictures below for the color difference between hetero and homobeige:

HOMOBEIGE (top) and HETEROBEIGE (bottom)

Recessive genes are genes that are ONLY expressed if you have two copies of them, thus an animal with one copy of violet will be…gray! A chin needs two copies of violet to be violet, and with only one, the animal will look gray and be a “violet carrier,” meaning he “carries” a violet gene but does not express it. An animal with two violet genes will be, guess what, a violet! Same with sapphire, and sapphire carriers.

TWO VIOLET CHINCHILLAS (top)

SAPPHIRE WRAP (bottom)

Whew, we’ve got the easy stuff done now, right? Well, not really. Remember I said violet and sapphire are on different genes from gray and beige, and from each other too…which means that although violet and sapphire “come out” when in double doses, SO DOES BEIGE if you have an animal that has a beige gene and double-violet or double-sapphire genes (and I suppose you could come up with an animal that had double violet, double sapphire and beige all together--that many mutation color genes tends to produce a unhealthy animal and the color combination might be only provable with subsequent matings--beige sapphire and beige violet can be bred but often are a sort of color-puzzle and hard to differentiate from straight beige--see below).
BEIGE SAPPHIRE

OK, now we get to the hard stuff: white, black and ebony genes. The hardest of these is the “black,” also known as ‘black velvet,” or “TOV” (touch of velvet). I think TOV is actually the best term, because this gene does NOT always produce a black chin--it accentuates a color the chin already has. And it is NOT an allele to gray, or beige, or violet or sapphire, it’s a separate gene altogether, and it is dominant, i.e. only one copy is needed for it to be expressed. So what does this mean? If you have a chin with a gray gene, if he has the TOV gene as well he will have a black face and back; a beige chin with the TOV gene will have a dark brown face and back, a violet or sapphire will also have accentuation of the underlying color especially on the face although the TOV effect with these colors can be subtle. And with white combinations, “seeing” the effect of TOV can be difficult if not impossible, and sometimes is only confirmed by subsequently mating the chin and having a TOV offspring. The other thing this “color” gene does is make the fur extra dense and strong, giving it a velvety feel, hence the name “velvet.” Astute genetics students will ask, “what does an animal with two TOV genes look like?” And the answer is--dead. This is a lethal gene in double doses, fetuses either don’t develop, die in utero or die shortly after birth, so the gene must be “linked” to other genes that in double doses produce some lethal defect, for example a weak heart (this is not known, I’m just giving you an example of something that could be the reason this gene in double doses is lethal). The other gene that is lethal in double doses is white.

BLACK VELVET (gray animal with TOV gene) (top)
BROWN VELVET (beige animal with TOV gene) (bottom)

OK, now white. Like TOV, white is a dominant gene in another location than any other color genes, so an animal can be beige combined with white, gray with white, violet with white, and sapphire with white. Ebony with white is a popular combination, and really this means gray-ebony because, like TOV, ebony is a gene that alters/intensifies a color already present. More on this later. All white-combo chins are unique--no two exactly alike, so if you like different, unique, one of a kind, then a white combo chin is for you. Sometimes people talk about simply “a white chin,” as if there were an all white chin--see above about why this cannot occur. Like TOV, white is lethal in double doses. However, some “pink whites,” which is white with beige, have so little beige that they appear to be all white, even though you can find a patch of beige, however small, somewhere. Other “pink whites” have quite a bit of beige, but the genetics are the same: a beige colored chin that also has the white gene. White with gray can produce white mosaic, with patches of gray, or white silver, in which the white and gray are so evenly distributed that the chin looks silver-colored--same genetics as white mosaic, however: white combined with gray.

PINK WHITE (white beige) brothers, one with a large beige patch, one with minimal beige in his face (top)
WHITE MOSAIC (white with gray) (middle)
WHITE EBONY, common pattern, Mom and daughter (near bottom)
WHITE EBONY with unusual mosaic-patches (far bottom)

The last common color gene is ebony, and this is a very odd gene that seems to have an “additive” effect. Chins are described, and judged in shows, as light ebony, medium ebony, dark ebony and extra dark ebony to indicate the degree of darkness and “wrap.” When ebony is talked about in this way, it is understood that this is really a “gray-ebony” combination, which “wraps” the color gray all around the chin, no white belly, and gives variable degrees of “darkening” of the gray from a little darker to a steel gray all the way around to an almost totally black chin. Although lighter degrees of ebony can be achieved with ebony from only one parent, extra dark ebony, truly black, chins generally inherit ebony from each parent to achieve this coloration. It’s hard to explain how this gene can be additive--maybe it comes in multiple copies and it is the number of copies that the animal inherits that determines “how ebony” it is. Breeders also talk about “ebony carriers” to indicate an animal that isn’t showing much ebony, if any at all, but passes more on to kits, and this is also hard to understand. Ebony combined with other colors, like violet and sapphire, produces a “wrap” of the underlying color all around the animal, and is called, e.g., a violet wrap or sapphire wrap; ebony with beige is commonly called “tan” instead of “beige wrap” and the animal will be brown all the way around. Sometimes the effect of ebony in a white combo chin is hard to see, but generally a white chin with black patches/areas is a white ebony, a very pretty and popular color combination.

MEDIUM EBONY (gray with ebony) with WHITE MOSAIC sibling (top)
EXTRA DARK EBONY (with ebony from both parents) (middle)
LIGHT TAN (beige with ebony) (bottom)

If you are a breeder and want to know what color kits you could have with different color of parents, there are tools to help you online (so called “chin calculators”), however, if you know your genetics, you can fairly easily figure out what color kits you MIGHT have, always recognizing that, in the end, the way the colors come out is up to chance, meaning you can know what you COULD get but you can‘t know which of those you WILL get.
And if you are NOT a breeder, if you still are reading, you might want to finish this section so you’ll have an understanding why breeders might tell you when you ask what they are expecting, “well, I COULD have white ebony, pink white, gray, ebony, tan or beige kits coming up,” by which they mean that because of the color of the soon-to-be-parents, these colors are all possible in kits but until the kits arrive, it’s a mystery. And breeders recognize that some of their chins tend to “throw” one color more than expected based on the genetics, for example, a white ebony mom who has more than 50% white kits or who never throws white--chances are the longer you breed that chin, the more the genetic possibilities will conform to the expected combinations, but not always. Another complication can be the presence of a “carrier” status, which, again, might mean that with two carriers you often get the color, or never (like violet or sapphire)--with time, and enough litters, you should see many, if not all, of the color combinations your chins can make, but not always.
Here is an easy Punnett square, which is a standard genetic tool to diagram the possible genetic possibilties in offspring--in this case, a standard gray female crossed with a heterobeige male.

Mom gametes>>            Gray           Gray
Dad gametes VV

Beige                              Beige          Beige

Gray                               Gray            Gray

The way to read this square is to place, across the top, the color chromosomes the mom can contribute (in this case, only gray), and on the side the color chromosomes the dad can contribute (and with this dad, heterobeige, he can pass on beige or gray in sperm)--the inside of the square shows how the colors combine to produce kits. Add up the kits and, in this case, 50% of the kits will be (hetero)beige and 50% will be gray. Pretty easy, huh?
Well, here is another, much harder Punnett square--a gray violet carrier mom crossed with a pink white violet carrier dad--that’s a lot of color genes for chins to carry by the way, and some breeders would say, stick to simpler matings. In case you are wondering, these two parents would “look” like a gray mom and a pink white (beige-white) dad, because the “violet carrier“ status is not expressed.

Your gray violet carrier can give you two types of gametes: gray with violet and plain gray. Your pink white (i.e. white with beige) violet carrier can give you all these gamete combinations:
White beige violet; beige violet; white beige, beige.
ARE WE DONE? Well….no. Is this a heterozygous pink white or a homozygous pink white? This is sometimes impossible to know until you mate the chin (and see what you get--if you got a gray kit from the pink white parent, then you KNOW the chin is NOT a homobeige, which can only give beige to its offspring). Some breeders say very light pink eyes indicates a homozygous pink white, meaning the animal has two copies of the beige gene, versus a heterozygous pink white, meaning the animal has only one copy of the beige gene. Why does this matter? Again, a homozygous beige animal can ONLY pass on beige, no “non-beige” (gray) gametes, therefore, ALL offspring will have at least one beige gene. Let’s do the Punnett square both ways.

MOM:>>                                                Violet                                    Gray

DAD: VV
HOMOBEIGE
white beige violet carrier:

White beige                                            white heterobeige                    white heterobeige
  Violet                                                           violet                                 violet carrier

Beige violet                                            heterobeige violet                    heterobeige violet carrier

White beige                                            white heterobeige                     white heterobeige
                                                                 violet carrier                      

Beige                                                     heterobeige violet                      heterobeige
                                                                    carrier


OUTCOME OF KITS GENETICALLY: l white beige-violet/2 white beige VC’s/l beige-violet/1 beige VC/l white beige/l beige/l beige VC
AND THEY WILL LOOK LIKE THIS: l white beige-violet/3 white beige/3 beige/l beige-violet

Dad: VV
HETEROBEIGE
white beige violet carrier

White beige                                            white heterobeige                     white heterobeige
Violet                                                              violet                                 violet carrier

Beige violet                                            heterobeige violet                      heterobeige violet
                                                                                                                     carrier

White beige                                           white heterobeige                       white heterobeige
                                                                violet carrier

Beige                                                     heterobeige violet                        heterobeige
                                                                     carrier

Violet                                                              violet                               gray violet carrier

Gray                                                           gray violet                               gray
                                                                     carrier

White gray violet                                          white violet                           white gray violet
                                                                                                                        carrier

White gray                                              white gray violet carrier                  white gray

You can figure out what the kits color genes will be and what the kits will be “phenotypically,” which is the genetic way of saying “what the animal looks like from the genes that are expressed.” Because white is dominant, exactly half the kits in this Punnett square are whites of some kind, because violet is recessive and each animal is a carrier, exactly one fourth of the kits are violets of some kind, and because beige is dominant, exactly half the kits are beige of some kind--but it’s the whole square that tells you, for example, what the chance of a white beige violet is in this match (l in l6).

And see what a difference having a heterobeige animal makes? It expands the combinations and gives the possibility of either gray or white gray (white mosaic) kits, whereas when the animal is homobeige, ALL the kits will have beige, whether with white or violet mixed in or not, because all will get that dominant beige gene from the homobeige parent. And keep in mind, all those ‘violet carriers’ will not “show” violet, they will simply express the color they are and carry the violet (important for breeding). Now, because I think it’s easier to remember what we’re talking about to call them the actual combination colors, remember that in most chin color terminology, white gray = white mosaic (or silver) and white beige = pink white.
That’s it, that’s all you need to go out and l) speak knowledgeably to breeders about the colors of chins and 2) figure out what kind of kits you can get from breeding different color chins. Good luck!

Back to the cute brother and sister from the start of this article, and you should know some possible parents by now--this homobeige boy and light ebony girl actually came from a pink white heterobeige mom and a heterobeige tan dad, but could have come from any two chin parents that each had only one beige gene and one parent with some ebony. And now you know why!