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White

Dark-Eared White (c^dc^d)

The year 2002 was the 45th birthday of the dark-eared white (DEW) hamster. First described by Roy Robinson in Nature in 1957, the DEW remains popular, and can often be found on the show bench. It is a little surprising that after 50 years of breeding, the true albino Syrian hamster has yet to occur. An albino Campbells Russian dwarf hamster has been known for some time, but its Syrian counterpart is still awaited.

An adult DEW has pure white fur, but pigment develops in the pinna of the ears from the age of about 30 days onwards, eventually attaining the same intensity of colour as the ears of a Golden. Pigment is also present in the perineal area, but lacking in the eyes which are clear pink. The DEW is not, therefore, a true albino, but is related to the acromelanic thermo-sensitive phenotype of, for example, the Himalayan rabbit or the Siamese cat. The DEW gene is symbolised c^d

It is inherited as a simple recessive, and is easy to breed on account of its ability to "mask" most other colour genes. One may think of the DEW as an erasing gene which, in the homozygote, removes pigment regardless of the genotype of the animal.

BHA Standard

Combinations of DEW with other genes produce few relevant interactions, but one is worthy of mention.

Flesh-Eared White (ppc^dc^d)

The Cinnamon gene (p) has the effect of removing much of the pigment from the ears and skin, giving the impression of a true albino animal. This is a standard variety.

BHA Standard

Anophthalmic (Eyeless) White (Wh)

In a letter to The American Naturalist in 1957, Byron H. Knapp and Sergey Polivanov described a new mutation which they named Anopthalmic Albino. Later authors suggest Anophthalmic White as a better description, and it is commonly referred to as "Eyeless White" in the Fancy. The gene has a poor reputation among breeders, because, as the name suggests, homozygotes (WhWh) are completely white with absent or rudimentary eyes. At first sight, such animals may look distressing as they are obviously blind. They will, however, attain a normal size and are able to breed. They do not live very long, about six to twelve months on average, possibly as a result of other internal anatomical abnormalities. It must be remembered that all hamsters have poor eyesight, and complete loss of sight is not a great handicap to a hamster. Anophthalmic white hamsters will feed normally and are generally very active. They require a little more care and attention when being tamed, but I have had two youngsters who ultimately became as a tame as normal hamsters. Perhaps understandably, many breeders prefer to avoid producing Eyeless Whites if at all possible. The nature of the gene makes this difficult, and I have been caught out once by crossing two carriers, one of which had very little evidence of carrying the Wh gene

Here is some general advice for determining whether a hamster carries the Wh gene

For other colours, the effect of Wh depends on whether the animal is an Agouti (has cheek flashes, crescents and the chest band) or is Self coloured (no markings, solid colour). For agouti colours such as Grey, Rust and Cinnamon, Wh will produce white belly fur and white ticking, in a manner similar to the Golden as described above. The amount of white is variable.

Roans

For Self colours such as Sable (U-ee), Chocolate ( U-eebb) and Mink (U-eepp), the Wh gene reduces colour over the dorsum (back) but the head retains more colour, albeit with a sprinkling of white hairs. These varieties are known as Roans

Roans/White Bellieds and Eyeless Whites cause a lot of confusion and are a regular source of questions so here is a brief FAQ:

• Q: Is Wh Dominant or Recessive ?

  A: Neither, really. All one can say is that the homozygote is an eyeless white, whereas the heterozygote (Whwh) is a white-bellied Agouti or a Roan. For convenience, it is usually labelled as a dominant gene, so that the genotype of an Eyeless White is WhWh.

• Q: I crossed two hamsters together and got Eyeless Whites, but neither of the parents were Roans or White Bellieds Why did this happen?

  A: It's very easily done when a cross is made between two white hamsters of uncertain parentage, or when Dominant Spot hamsters carry the Eyeless White gene. I once crossed two Dominant Spot hamsters together, not knowing that they both carried Eyeless White, as they had come from a pet shop, and accidentally got Eyeless Whites

• Q: How do I know when a Banded or Dom Spot hamster is carrying the Anophthalmic White gene?

  A: It can be very difficult (if not impossible) to identify the Wh gene in a Banded or Dom Spot hamster. In a banded, look for a suffusion of white hairs around the face. In a dom spot, pure white belly fur and white spotting on the face/forehead is the norm, so that's no help. Caution is required!

• Q: How can I produce Roans or White-Bellied hamsters without producing Eyeless Whites ?

  A: To produce Roans or White Bellied hamsters, you must have one to begin with! By definition, a Wh carrier is a Roan or White Bellied with the features described above. Always cross to a Normal, and on average the litter will have the following colours:

  Colour		Roan/White Bellied
  	Parental Genes	Wh	wh
  Normal	wh	Whwh Roan/White-bellied	whwh Normal
  	wh	Whwh Roan/White-bellied	whwh Normal

• Q: How do I get Black Eyed Whites using the Eyeless White Gene?

  A: Because it is a sort of white patterning gene, Wh will interact with the other white patterning genes, namely Dominant Spot (Ds) and Banded (Ba). The combination of Cream (ee), Anophthalmic White (Wh), Dominant Spot (Ds) and Banded (Ba) will generally produce a completely white hamster with dark eyes and pale ears. On close inspection, the eye colour will be seen to be deep ruby rather than black. The precautions outlined above should also be taken with this colour, as it is perfectly capable of producing Eyeless Whites if mated to a Roan or White Bellied hamster. A better way of producing black-eyed whites is to combine Silver Grey and Cream.

Hopefully this information will be of help to breeders trying to work with this useful, but tricky gene.

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