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Lesson 3 Silver and Other colors . . . |
| And, now by popular
demand: Silver
Silver is not hard, genetically, to understand. It is dominant and therefore cannot be carried. In other words, to produce a silver kitten, one parent must be silver. But for some reason, in Bengals, it is confusing. I personally believe this is because as an unrecognized color many didn't know it existed so were not looking for it in their litters. The other reason seems to be that it can and is confused with Sepia (phenotypically) and some cannot identify one from the other. Therefore many kittens have been miss-registered and what is on the pedigree may be a color other than the actual genetic color. Silver, like "snow", is not a color. I think a lot of the confusion over silver comes from thinking of it as a color. Any other color, including Lynx point, can be 'silvered'. The inhibitor gene which produces the silver, interferes with the synthesis of the color granules and blocks their entrance into the hair shaft during embryonic development of the background (agouti) hairs, leaving the tabby pattern hairs unaffected. So, a silver Bengal is still genetically a Black cat with the ground color inhibited. [i.e.: Think of a normal cat as a lady having dark brown hair and then bleaching it blond, this lady still is a brunette but she now looks blond. The inhibitor gene acts much the same way. So, the genetic make-up of the cat in all other areas is still there (ie: black) but the ground color is just inhibited from being seen.] That said, lets us deal with some commonly asked questions: 1. "If Silver is dominant and Brown (genetically black) is dominant, how can silver carry Black?" Here is where remembering that silver is not a color is helpful. A silver Bengal is still a genetically black cat (usually). So, if you breed a mink queen to a sepia stud and you get a BST kitten -- what happened? First of all, you know that neither mink nor sepia can produce black (BST). But, remember that silver is not a color and is influencing different genes (inhibitor genes); therefore, one did not dominate the other, you just see the effect of the silver and not the black because the action of one stops the action of the other. (Like our example above.) You can conclude, now, that one of your parents is a silver. Ok, so you look over your parents and determine which one is the silver. Most likely it will be the "sepia" as that is the easiest color to fool you, especially when you're not familiar with both sepia and silver. So, your "sepia" (that you now know is silver) is genetically: CcsIi and when bred to spotted mink (cbcsii) produces the following possibilities: |
Silver (Supposed to be Sepia) Spotted carrying Lynx pt X Mink Spotted=
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| # | Genotype: | Phenotype: |
| 2 | CcbIi | Silver carrying Sepia |
| 2 | Ccbii | Brown carrying Sepia |
| 2 | cbcsIi | Silver mink |
| 2 | cbcsii | mink |
| 2 | CcsIi | Silver carrying Lynx point |
| 2 | Ccsii | Brown carrying Lynx point |
| 2 | cscsIi | Silver Lynx point |
| 2 | cscsii | Lynx point |
| (I assumed that the silver carries for Lynx point because Lynx point is so common and because this cat came labeled "sepia" so probably from a snow breeding program.) |
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Pretty much an equal chance of getting each possible combination in this
case. You would not know who was carrying the recessives in the silvers
and blacks. [FYI this is a litter I actually bred and produced.
Out of 5 kittens we got 2 mink, 1 bst, and 2 silvers. We would not
at that time have been able to distinguish a silver mink or a silver Lynx
point, so it is a miracle those did not show up. <g>)
Note: Had the silver in the above example been homozygous for the inhibitor gene (II), all kittens would have been silver, silver mink, or silver Lynx point. It would have been easy for a newbie to assume this was an all "snow" litter with "sepias", minks, and Lynx points. Also, if the one BST had not shown up, we would still have had the same circumstances. The newbie producing this litter might never know what she had or was selling. (I think this is exactly where some of our incorrectly classified cats come from.) |
| Here
is how this works:
If the (I) gene is present, the cat will be silver. Silver can be homozygous (II) or heterozygous (Ii). In the example above, we assumed that the silver was heterozygous for silver (outside of a silver breeding program, I doubt if many silvers will be homozygous.) For the silver to "appear" to carry brown, it must be heterozygous for silver as it is the non-inhibitor (i) gene that is carried allowing the brown (black) to show up; not the brown (black) color being carried which is there all along. While silver cannot carry black (brown), you can see by this litter how it can appear to carry it. You can also see the importance of being able to identify it, if you're going to be working with it. Or, if you're going to work with colors where you might be offered a "sepia/mink", Lynx point, or "unrufoused" BST that may be miss classified. To identify silver look for black paw pads, black markings, and a black tail tip. [Seal is not quite black and if the tail tip is placed next to something that is a true black, it will be slightly lighter (seal), also a mink or sepia cannot have black markings because of the action of the albino genes (see the lesson on snows). Their darkest markings will be very dark brown or charcoal - never black. Also, in an adult silver the eye color is often a brilliant beautiful green, in an adult green eyed sepia or mink the eye color is the result of the reduced pigment in the cornea from the albino gene and will not be that bright. The white parts (under sides, under coat, and the base of the hairs) will be bright white on a silver and an off-white or soft white on any of the "snows". |
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2. "I think one of my kittens is a silver, but neither parent is silver,
how can this be?"
It can't. If you have truly gotten a silver in a litter with no silver parents, you've got to really look those parents over. One of them IS silver or a silvered Lynx or a silvered something. Sometimes a silver will have enough "tarnish" to look like a bad brown spotted (not very rufoused). Or, a Lynx point will surprise you because the normally light undercoat camouflages the silver. When I was researching our situation with the silver male that was supposed to be sepia, one person told me (speaking of this stud's mother) "I've seen her and she's definitely a BST just not very rufoused." This is how mistakes happen, the cat this person was talking about in the long run DID turn out in fact to be silver. She is still breeding in England and is now classified as silver. When in doubt, have someone knowledgeable look over your cat(s). A judge or a breeder knowledgeable in silvers. Get familiar with your genetics and your pedigrees. Genetics IS a science and it does follow the rules - even if it doesn't seem like it sometimes to those who don't understand its complexities. <g> When you have identified a cat in one of your pedigrees as a silver, then there must (no exceptions) be a silver parent in each and every generation all the way back. One of it's parents must be silver, one of that cat's parents must be silver and so on. |
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The hardest part of breeding silvers is probably not the genetics.
If you want silvers, buy a silver and you'll get silvers. But, if
working with silvers and improving them is your goal there are other factors
to consider. To rid your lines of tarnishing, breeding for homozygous
lines (II) is beneficial. This would require breeding silver to silver
until all cats are (II) homozygous.
Myths: 2. "Breeding to snows produces clear coats." If the coat of the snow is not clear this will no more produce clear coated kittens than if you breed to another color with a unclear coat. The clearness of the coat or lack of ticking is an altogether different gene than the color genes. (And, not related to the albinism genes.) 3. "Breeding to silver will ruin your chances to sell the non silver kittens in that litter." If your buying public is knowledgeable, there should be no problem selling these kittens even to breeders. The silver can't be carried, so if you've done your job and properly identified your kittens there should be no problem and those that have a problem with these kittens are showing their ignorance. I used one of the mink girls out of the cross with the silver male in my program and she produced lovely kittens, she is now producing kittens in Denmark, |
>^.-.^<
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We have briefly touched on other colors as we've gone along, so there is not a lot left to cover here but here is the rest of the story and some added details. Blue, Chocolate, Melanistic Chocolate is a change of the black color gene to brown which is still carried at the same locus (location) on the chromosome. A chocolate full color Bengal will have brown markings instead of black and a brown tail tip with paw pads that are rose or at least more than "rosy undertones". The markings and tail tip with be a color like that of a Havana Brown. A chocolate mink/sepia or Lynx point will also have a brown tail tip with rose paw pads or again, more rosy then "rosy undertones".) Probably the best indicator here is the tail tip but don't panic too early, I had a kitten last spring I thought was a chocolate mink and by 5-6 months she had developed the deep seal tail tips and proper pad color. Melanistic was discussed in the first lesson on Agouti and Ticking. Torbies Lockets
Lockets are the result of the very dominant white spotting gene.
The exact inheritance of which was still under discussion when Robinson's
3rd Edition was published. However, there is plenty of evidence that
it is quite dominant. The question seems to be if more than one gene
is involved in the inheritance or exactly how the expression is influenced.
Suffice it to say, for Bengal breeders this is an insidious gene and one
that is not wanted. Yes, I've said in these lessons that a dominant
gene is easier to rid yourself of than a recessive one. BUT, just
a few unnoticed white hairs (perhaps hidden in the lighter golden undercoat
of your BST, or on your Lynx point's light undersides) can result in a
locket "out of no where" when these cats are bred.
Answer
to Last lesson's Question: You are expecting a litter
of kittens from your a beautiful seal Lynx point spotted queen
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