Description:
Silver is a mutation found on the same gene for both Coturnix quail and mice, and is similar to a mutation in humans as well (1). It is best studied in mice, though a few studies have been done on quail (1)(2). It is unknown if this is the same gene that causes silver in button quail.
Silver in coturnix is a light grey color (1) across the bird in heterozygous form (one copy of the gene), but has the same underlying base pattern, just with a different color. The bird may or may not have white wingtips without any additional white mutations. In homozygous form (two copies of the gene), the bird will be a pale cream, almost white color (1). It is considered part of the Schofield Silver Collection, along with Andalusian and Lavender.
Silver in mice presents as a grey colored coat in heterozygous form, and a light cream in homozygous form, similar to in birds (2).
In homozygous form for both species, there is a semi-lethal gene involved (1). For quail, a majority of the chicks with two copies of silver will die in the shell, and the birds that survive and hatch will often be blind and not survive to adulthood (3). For mammals, it can cause issues with pigmentation, vision, and other defects (2), including Waardenburg Type II in humans.
Silver as we know it in quail is typically heterozygous form. Therefore, homozygous silver will be referred to as "cream" below (many Cream will not hatch or have defects) while het. Silver will just be called Silver. Clean refers to any animal without one or two copies of the silver gene. A Pharaoh bird would be clean.
Breeding with Silver:
Cream x Cream = 100% Cream
Cream x Clean = 100% Silver
Cream x Silver = 50% Silver, 50% Cream
Silver x Silver = 25% Cream, 50% Silver, 25% Clean
Silver x Clean = 50% Silver, 50% Clean (most recommended for breeding to avoid defects)
References & Further Reading
Minvielle, F., Bed'Hom, B., Coville, J. L., Ito, S. I., Inoue-Murayama, M., & Gourichon, D. (2010). The" silver" Japanese quail and the MITF gene: causal mutation, associated traits and homology with the" blue" chicken plumage. Bmc Genetics, 11, 1-7.
Steingrímsson, E., Moore, K., Lamoreux, M. et al. Molecular basis of mouse microphthalmia (mi) mutations helps explain their developmental and phenotypic consequences. Nat Genet 8, 256–263 (1994). https://doi.org/10.1038/ng1194-256
Araki, M., Yamao, M., & Tsudzuki, M. (1998). Early embryonic interaction of retinal pigment epithelium and mesenchymal tissue induces conversion of pigment epithelium to neural retinal fate in the silver mutation of the Japanese quail. Development, growth & differentiation, 40(2), 167-176.
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