This is a quick and short article about WWs' genetics. It is important to know that this works only in case of pure Winter White Russian Dwarf Hamsters and can not be implied in cases of hybrids/puddings, moscows, marbeleds, mushrooms, mandarins or any other unsubstantiated WW hamster colours. So here it is:
There are three known WW genes: Agouti (A), Sapphire (S) and Pearl (Pe). There are also claimed to be other pure genes as Marbeled/Merle (Me), Mandarin (Ma) and Imperial (Im), but those are believed to be either result of hybridizing (Me,Ma) or extinct (Im). I am gonna work with only the basic 3. There is the difference between colour and pattern; coulour means which colour hamster's fur will be and pattern is the factor that causes the amount of colouring showing up (or lack of coulouring in case of some Pearls).
1) AGOUTI: Agouti (a.k.a. Wild) is a colour of wild animal, and is the dominant gene for Winter Whites. My past hamster Bella used to be Agouti coloured. Since Agouti is dominant gene; it's geotype is either AA (homozygous Agouti; carries two Agouti genes) or AS (heterozygous Agouti; meaning animal carries one Agouti gene and one Sapphire gene). No matter AA or AS; the animal will always be Agouti coloured.
Bella, an Agouti Winter White
2) SAPPHIRE: Sapphire is the other colouring gene in Winter White that makes hamster's fur grey/blueish. This colour mutation doesn't occur in wilderness and was produced in captivity by selective breeding. It is basically a mutation that occured once and was spread by breeding Sapphires to Sapphires or Sapphire carriers (AS). The genotype is SS (homozygous Sapphire, since heterozygous AS would be an Agouti coloured Sapphire carrier). Since Sapphire is recessive gene, it's maybe more tricky to work with then Agouti.
Sheldon (dad) and Aiden (son), two of my Sapphire Winter Whites
3) PEARL: Most considere Pearl to be the rearest colour that WWs come in. Wrong and wrong. First off, many don't understand that Pearl (Pe) is a mutated gene that actually masks hamster into their white winter coat year round. As stated previously; WWs come only in Agouti or Sapphire colours, and wether they are gonna show it or not is thanks to Pearl gene. Pearl gene is dominant, as opposed to a non-pearl state (non-pearl is not a gene, as it's only possible pattern in the wilderness, and is marked as either pe or - in genotypes). So, considering all that, your Pearl hamster could be either PePe (homozygous Pearl, means all it's offspring will turn out Pearl) or Pepe/Pe- heterozygous Pearl, carries one Pearl gene and lack the other one). Breeding Pearls is mostly done in Pearl-exclusive lines, as you may (will) lost the track of what colour Pearl masks. As of today, there is no way to tell Agouti Pearl from Sapphire Pearl without testing breedings. Pearls can be either pure white or so called dirty (displaying darker marks on the back or entire dorsal stripe, occasional darker spots on ears or between eyes). Number of Pe genes doesn't affect wether hamster will be pure white Pearl or dirty Pearl.
Sevan, my dirty Pearl (visable dosral stripe and darker spot on her head)
This is how far my knowledge in Winter Whites' genetics go. I could rambble about other (new) coulour variations, but those are not fully researched yet. I do think I read that Mandarin gene (Ma), causing a orange/creamish is domiant, but those hamster are breed mosty in Asia (and recently in wester Europe and USA) and some do breed their pets to get that coulours, but no matter if you know all the genetics or nothing, leave breeding to profesioal breeders that know what they are doing.
