The Belt mutation in pigs is an allele at the Dominant white (I/KIT) locus

A white belt is a common coal color phenotype in pigs and is determined by a dominant allele (Be). Here we present the result of a genome scan perform ed using a Hampshire (Belt)/ Pietrain (non-Belt) backcross segregating for the white belt trait. We demonstrate that Belt maps to the centromeric regi on of pig Chromosome (Chr) 8 harboring the Dominant white (IlKIT) locus. Co mplete cosegregation between Belt and a single nucleotide polymorphism in t he KIT gene was observed. Another potential candidate gene, the endothelin receptor type A gene (EDNRA), was excluded as it was assigned to a differen t region (SSC8q21) by FISH analysis. We argue that Belt is a regulatory KIT mutation on the basis of comparative data on mouse KIT mutants and our pre vious sequence analysis of the KIT coding sequence from a Hampshire pig. Qu antitative PCR analysis revealed that Belt is not associated with a KIT dup lication, as is the case for the Patch and Dominant white alleles. Thus, Be lt is a fourth allele at the Dominant white locus, and we suggest that it i s denoted I-Be.