The mutation causing the black-and-tan pigmentation phenotype of Mangalitza pigs maps to the porcine ASIP locus but does not affect its coding sequence
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The gene for agouti signaling protein (ASIP) is centrally involved in the expression of coat color traits in animals. The Mangalitza pig breed is characterized by a black-and-tan phenotype with black dorsal pigmentation and yellow or white ventral pigmentation. We investigated a Mangalitza × Piétrain cross and observed a coat color segregation pattern in the F2 generation that can be explained by virtue of two alleles at the MC1R locus and two alleles at the ASIP locus. Complete linkage of the black-and-tan phenotype to microsatellite alleles at the ASIP locus on SSC 17q21 was observed. Corroborated by the knowledge of similar mouse coat color mutants, it seems therefore conceivable that the black-and-tan pigmentation of Mangalitza pigs is caused by an ASIP allele a t , which is recessive to the wild-type allele A. Toward positional cloning of the a t mutation, a 200-kb genomic BAC/PAC contig of this chromosomal region has been constructed and subsequently sequenced. Full-length ASIP cDNAs obtained by RACE differed in their 5′ untranslated regions, whereas they shared a common open reading frame. Comparative sequencing of all ASIP exons and ASIP cDNAs between Mangalitza and Piétrain pigs did not reveal any differences associated with the coat color phenotype. Relative qRT-PCR analyses showed different dorsoventral skin expression intensities of the five ASIP transcripts in black-and-tan Mangalitza. The a t mutation is therefore probably a regulatory ASIP mutation that alters its dorsoventral expression pattern.
KeywordsCoat Color Dorsal Skin Resource Population Ventral Skin Untranslated Exon
The authors thank D. Seinige, H. Klippert–Hasberg, S. Neander, and B. Hayn for expert technical assistance, the staff of the Experimental Station Thalhausen of the Technical University of Munich for careful animal husbandry, and D. Fries for the color phenotyping of F2 animals. They also thank P. de Jong and his lab for providing the RPCI-44 library and excellent supplementary information. This study was supported by a grant of the German Research Council DFG (Le 1032/12-1) to TL.
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