Categories: Pigmentation phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 155550 (gene)

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal dominant

Disease-related: no

Key variant known: yes

Year key variant first reported: 2004

Species-specific description: Kerje et al. (2004) showed that three alleles at the Dominant White locus in chickens (namely Dominant white, Dun, and Smoky) are all caused by mutations in the gene for the melanocyte-specific protein PMEL17, which is chickens is called PMEL.

History: This trait was one of the five first animal traits (all in chickens) whose Mendelian inheritance was documented (by Bateson and Saunders, 1902; pages 87-124) after the rediscovery of Mendel's result. The other four traits are Rose-comb (OMIA 000884-9031), Pea-comb (OMIA 000782-9031), Polydactyly (OMIA 000810-9031) and Yellow skin (OMIA 001449-9031).

Molecular basis: Adopting a comparative positional cloning approach (by noting that the chromosomal region to which this trait maps in chickens is orthologous with the region of mouse chromosome MMU 10 that includes the PMEL17 gene which when mutated causes the silver mutation in mice), Kerje et al. (2004) were able to identfy the causal mutation: "The Dominant white allele [is] exclusively associated with a 9-bp insertion in exon 10 [of the PMEL17 gene], leading to an insertion of three amino acids in the PMEL17 transmembrane region. Similarly, a deletion of five amino acids in the transmembrane region occurs in the protein encoded by Dun. The Smoky allele shared the 9-bp insertion in exon 10 with Dominant white, as expected from its origin, but also had a deletion of 12 nucleotides in exon 6, eliminating four amino acids from the mature protein." (Kerje et al., 2004). In chickens, the gene encoding PMEL17 is called PMEL.

Breed: White Leghorn (Chicken) (VBO_0000646).
Breeds in which the phene has been documented. (If a likely causal variant has been documented for the phene, see the variant table breeds in which the variant has been reported).

Associated gene: