White Kittens

[azriel]

Hi, I was curious if anyone could help with information of my cat's color genes. I adopted 2 female kittens from a litter of 4. The mother was a brown tabby with copper eyes (She might have had some white coloring on her chest/stomach, but I can't remember). In the litter, 3 of the kittens were white a small grey smudge on their heads and 1 kitten was all white. I adopted the all white kitten (copper eyes) and one of the kittens with the smudge (light green eyes) and her smudge has faded, she is now all white.

After doing research online, I read that my kittens were either SS or (ss + Ww/WW).

With this information, would anyone be able to tell me what color the sire would have been? I'm just curious if that could be determined from this information. Thanks!

 

[maewkaew]

Sire was very likely solid White himself,  and the kittens Ww.       For a cat to be all white,  it is  far, far more likely for that to result from Epistatic White / "Dominant White"  (W)    than homozygous White Spotting (SS) .

    It can happen that 2 copies of S can result in such an extreme expression of white spotting that the cat is entirely covered with the white patches.    So if it's possible the dam had some white on her,  it can't be 100% ruled out that the sire is  "and White" ( with the other color being some black-based color since the female kitten had grey kitten caps .

But that is rare that S/S results in a totally white cat.    More usually it's a van pattern or harlequin pattern or  bicolor.   So for THREE kittens in the litter to turn out solid white,  it would be extremely rare that that could be from White Spotting.  That is virtually certain to be W. 

The kitten caps ( smudge on head of a white kitten at birth)  happens often with kittens who have W.   It doesn't mean that the kitten is really SS.  

You wrote "I read that my kittens were either SS or (ss + Ww/WW)"

That's not quite right.   It's true that the kittens are either SS  ( unlikely)  or Ww ( very likely) .  

But  1. There is no way the kittens could be WW,  because the mother is not solid white.    W is dominant,  it can't be carried hidden.  If she could pass it on to kittens, she would have to show it herself.

And 2.  re the "ss + Ww ",   we don't know the ss part.   There could be any possible combination at the White Spotting locus  --  SS, Ss or ss.    But Epistatic White will overrule everything.  .   So it could be ss Ww  or  Ss Ww or SS Ww.      If a kitten has a W ,  the phenotype will be white.  You can't tell by looking whether the kitten would have had white patches if it didn't have W.   

I hope maybe this helped to explain. 

 You may be interested in this article by feline geneticist Lorraine Shelton  . http://home.earthlink.net/~featherland/off/white.html