Categories: Pigmentation phene

Mendelian trait/disorder: yes

Mode of inheritance: Z-linked recessive

Disease-related: yes

Key variant known: no

Mapping: McGibbon (1979) reported this trait to be allelic with Inhibitor of dermal melanin (Id; OMIA 001699-9031). Consistent with this, Dorshorst (pers. comm.) reported that the trait is due to interaction between the Id locus and the locus for yellow skin (OMIA 001449-9031). Siwek et al. (2013) conducted a GWAS on 84 chickens from 35 traditional European breeds (including the Green-legged Partridgelike) and 6 representative jungle fowl species, each genotyped with the 60K SNP Illumina iSelect SNP chip, and each with an inferred genotype at three loci, namely Skin colour, yellow (W; OMIA 001449-9031), Inhibitor of dermal melanin (Id; OMIA 001699-9031), and Silky/Silkie pigmentation (Fibromelanosis) (Fm; OMIA 001671-9031). For each of the three loci, binomial association tests were conducted on a subset of the genotyped birds (having firmly-established genotypes at that locus) with that locus and each SNP. From their results, the authors concluded that "an interaction between the recessive yellow skin allele and the wild recessive allele at the dermal melanin locus present in the Silkie is responsible for the green shank phenotype", thereby confirming Dorshorst (pers. comm.).