In other species: Arabian camel , golden hamster

Categories: Pigmentation phene

Mendelian trait/disorder: no

Disease-related: no

Key variant known: no

Inheritance: Despite the word "mutation" appearing in the title of his paper, Gregory (1950) provided no evidence for any form of inheritance (single-locus or otherwise) for the piebald phenotype exhibited by the single sheep he reported. Investigations of the inheritance of this phenotype (e.g. by Brooker and Dolling, 1969) ruled out any single-locus form of inheritance. Decades later, in a landmark paper combining the power of SNP-based genome-wide association analysis and network analysis of gene expression data, Garcia-Gámez et al. (2011) showed clearly the multifactorial nature of inheritance of this trait, and were able to identify several genes showing relevant differential expression that are located in the regions of highly-associated SNPs (see section on Molecular basis).

Molecular basis: Garcia-Gámez et al. (2011) identified thirteen genes at the intersection of two inferred networks (one regulatory and the other epistatic), "with insulin-like growth factor binding protein 7 (IGFBP7), platelet-derived growth factor alpha (PDGFRA) and the tetraspanin platelet activator CD9 at the kernel of the intersection". They also identified "differentially expressed genes in regions containing highly associated SNP including ATRN, DOCK7, FGFR1OP, GLI3, SILV and TBX15". Reverter and Fortes (2013) reviewed this work.