Genetic Interactions Among Three Pigmentation Loci in Domestic Dogs

Abstract Text: This paper focuses on the genetic interactions among three genes in the pigmentation pathway:  the Agouti signal protein (ASIP), Melanocortin receptor 1 (MC1R) and Beta-defensin 103 (DEFB103).  There are currently four ASIP or A alleles (a^y > a^w > a^t > a), four MC1R or E alleles (E^M > E^G > E > e) and three DEFB103 or K alleles, only two of which (K^B > k^y) are discussed here.  However, because of epistasis and gene interactions we suggest are either multiple modification since multiple genotypes are affected, or specific modification since only a single genotype is affected, there are 10 coat color phenotypes produced. The mutations responsible for these alleles are reviewed and their mechanisms within the pigmentation pathway are discussed.  The mutations include nonsynonymous substitutions, premature termination, and deletions with the coding sequences of these genes, as well as promoter mutations.

Keywords:

ASIP

MC1R

DEFB103

coat color

epistasis

modifier