Genetics and genomics of pigmentation variability in pigs: A review

Among the phenotypic hallmarks of the domestication process of the pig, that independently started in China and East Anatolia and continued in Europe and throughout China, coat colour was one of the earliest targets that was used to differentiate human managed animal cohorts from wild-related populations. In the modern pig breeding and conservation programs for local genetic resources, coat colour has important economic relevance. This review on the genetics and genomics of pigmentation variability in Sus scrofa summarizes all recent developments, concepts and applications derived by the genomic characterization of loci affecting coat colour and eye colour in the pig. It includes a general overview of the biology of pigmentation in mammals, a brief description of the types of coat colours and eye colour patterns in the pig, an overview of the coat colour loci described by classical genetic studies in this species, a detailed description of the genomic regions, genes and their mutations affecting pigmentation in Sus scrofa (including a revisited analysis of the variability in the MC1R and KIT genes and in several other genes: ASIP, TYRP1, EDNRB, KITLG, OCA2 and SLC45A2) and the application of the related available genomic information in selection and breeding plans and for the authenticity of pork products.