~< Silver Genetics >~

Silver is a relatively new color in Bengal breeding, and can be quite tricky to breed.  What I am going to share here is a combination of things I know about genetics in general, and things I have heard and seen since I became interested in breeding silver bengals.  If there are any errors in what I say, I apologize.  Feel free to correct me if I am in error.  I welcome any information that will make this document more complete and more accurate.      It is somewhat misleading to talk about silver as a "color", because the source of the silver "color " is an inhibitor gene.  It is not a stand alone color gene like brown etc.  Instead the silver gene is an inhibitor of the existing background color.  Just like human's natural hair color is rarely gray, it can become so as we grow old because of a lack of pigment.  The silver gene essentially makes cats go gray from birth by inhibiting their background pigment.  Sometimes this inhibition is incomplete.  The common term for this incomplete inhibition is "tarnish".  Which is also misleading, since tarnish on metal occurs due to oxidation of the surface of the metal after it is exposed to the elements, and in our case the "tarnish" was there first and has just failed to be inhibited.  So to help the reader understand the true nature of the observations being made, I am going to refer to "tarnish" as failed inhibition.  Inhibition failure can manifest in several different ways.  Sometimes the failure is localized, like a brown strip of fur down the back of a cat that is otherwise silver.  Sometimes the failure can be partial everywhere giving the cat a faded color appearance.  Sometimes a variation of the following can occur where for whatever reason most background hairs have no pigment, but ~20% of the guard hairs growing out everywhere are totally uninhibited.  Sometimes cats have a silver background and brown spots, and I have even seen silver cats with black bordered rosettes that are filled in with brown.      Because of the complex nature of the "color" it is difficult to judge what will work and what will not work in silver breeding.  Another common problem is variation in quality of the color and contrast with time.  Some silver cats are born with incomplete inhibition in one form or another and inhibition becomes more complete with age.  Other times silver kittens start off with stunning contrast only to fade as they get older.  These same faded cats can also give birth to kittens with stunning contrast later on.  So it's difficult to judge what to expect.  Below are some young to older kitten pictures.  Try scrolling down just far enough to see the young kitten pictures and try to guess who will look nicer with age.

I have heard a lot of things about which colors to breed and which colors not to breed with silver.  I'll briefly mention what I have discussed with other breeders and attmpt to understand what the advice means with respect to genetics and inhibition.  I have heard that it is best to breed "cooler" brown colors rather than "warmer" brown colors.  Cool refers to those "brown" bengals who almost look a dark grayish color, and "warm" refers to those "brown" bengals with more of an orange or rufus hue.  I think this probably has more to do with the fact that dark gray showing through the silver inhibitor is much less obvious than orange, because I have seen silver cats with little tarnish come from a rufus parent.  I've heard not to breed snow into silver, but again, I have seen gorgeous silvers come out of snow breedings, but I think the complication is telling who is what from birth, because it is not entirely obvious until the kittens are much older.  Furthermore I suspect some combination of albinism and silver could lead to very poorly contrasted silvers.  Both parents of this little guy on the left carried for snow, and while his eye color doesn't suggest albinism, I wonder if the snow genetics may be what diminished his contrast from birth to 5 months.  This is entirely speculation, because I understand little about snow genetics.  Perhaps someone would care to enlighten me.       Unlike snow, silver canot be "carried".  Silver is dominant, while not always entirely inhibiting, it does exhibit itself to some degree when present.  Many characteristic silvers only have one silver gene rather than two.  The chief example is Silvergene Splendor of Starbengal, who's father Dicaprio of Starbengal is quite clearly a brown stud.  When the number of silver zygotes (genetic pieces receieved from either parent) does matter is when you're trying to figure out what color babies to expect from a given pairing of cats.  This is where you will hear the terms heterozygous and homozygous.  Heterozygous for silver means that a silver cat only has one silver inhibitor gene.  The prefix Hetero- denotes that whatever you're refering to is not all the same, and since you're refering to zygotes for a particular trait where there are only two possibilities (silver and not silver) hetero means one silver and one not silver.  Homozygous means all the zygotes in question are the same, so a cat that is homozygous for silver has two silver inhibitor genes.  So if you mate a homozygous silver female to a brown male, every baby will get one silver inhibitor from the mother since she only has silver ones to give, and they'll get one "not silver" gene from the brown father since that's all he has to give.  So all the babies will be silver.  If you mated one of those babies to a brown bengal, you would get half of the babies getting one silver gene from mom.  If you mated that same silver cat to another cat with only one silver gene, you would get 3/4 silver babies and 1/4 brown babies, with one out of 3 of the silver babies getting 2 silver inhibitor genes.  I'll make a chart here below to clarify. On the chart br will stand for a brown zygote with no silver inhibitor, and brS is a brown zygote with a silver inhibitor.  Every cat has two zygotes and donates only one to each of its offspring. Homozygous silver Mom and brown Dad                                 Dad                             br            br M           brS    brbrS      brbrS o m          brS    brbrS      brbrS                       ^^^^^^^^^^^^^^^                     baby gene possibilities note: all babies have one inhibitor, so they are all silver Heterozygous silver Mom and heterozygous silver Dad                                  Dad                          brS            br M            brS  brSbrS      brbrS o m            br    brbrS        brbr                       ^^^^^^^^^^^^^^^                      baby gene possibilities note: three babies have at least one inhibitor and are silver, while one of those three has two inhibitors and one baby has no inhibitor and is brown Heterozygous silver Mom and brown Dad                                  Dad                            br             br M             brS   brbrS       brbrS o m              br    brbr           brbr                         ^^^^^^^^^^^^^^^                         baby gene possibilities note: Two babies are silver with only one silver inhibitor, and the other two babies are brown

Where Silver Bengals Come From

Part Mau Silver Part Shorthair Silver Plus help from Thomwren genes made these heads.

<--Shorthair Silver Bred                          Bengal         Photos Courtesy of               Julie Helm       Cedar Ranch Bengals Egyptian Mau Silver Bred-->                           Bengal

There are two breeds that I know of that have been used to incorporate the silver gene into bengals: the American Shorthair Silver, and the Egyptian Mau Silver.  Both have benefits and drawbacks.  The Shorthair Silver provides beautiful contrast, and clear coats, but also donates a stubby cobby face vertically linear markings, and a squat body which is hardly desireable in bengal breeding.  There's a reason why all of those beautifully clear coated silver bengals never have their faces towards the camera in website pictures (My babies don't have much to hide in the face because they have much less silver shorthair.).  The Egyptian Mau lends a much sleeker, less domesticated looking body and face, but also brings in ticking in the fur and smaller spots.  The above kittens have about half of each breed in their silver backgrounds, plus an additional generation of brown bengal to silver breeding.  You can see they are rosetted up front and in the middle of their patterns, but have smaller spots in the rear, and their heads are much more bengal like than the above silver shorthair bred bengal.  Breeding nice brown cats to silver cats probably does more good than bad for silver genetics as long as whatever color of brown the brown male is, is well inhibited in the offspring, and the brown male is of a quality such that the offspring can maintain contrast.  Silver to silver breedings don't always produce better kittens, but do potentially produce homozygous silver breeding cats.  If you are a big cattery trying to breed silvers and you already have brown queens, homozygous is probably good, but if you are a small cattery with only a few cats heterozygous will give you some diversity in your litter for those people who just prefer brown.  Silver genes do produce some of the best looking browns.  All of that attention to working on contrast and coats pays off for the brown offspring. That's all for now until I learn anything new or care to expound on the genetics of ticking and glitter etc.  When I figure that stuff out well enough I'll write something here about it.