Genetics
The dilute gene d is recessive to the wild type allele D. A gene test can be used to determine a dog's genotype concerning genes for pigmentation. In some lightened by the dilute gene, the mutation d is associated with color dilution alopecia (CDA). Since not all breeds in which the gene occurs exhibit these problems, it is suspected that there may be a second previously unknown mutation of the MLPH gene.[Ute Philipp, Henning Hamann, Sheila Schmutz et al.: within the canine MLPH gene are associated with dilute coat color in dogs. In: BMC Genetcs, 2005.][ U. Philipp, P. Quignon, A. Scott, C. Andre, M. Breen, T. Leeb: Chromosomal assignment of the canine melanophilin gene (MLPH): a candidate gene for coat color dilution in Pinschers. In: J Hered. 96(7), 2005, page 774–776. June 15, 2005.][ C. Drogemuller, U. Philipp, B. Haase, A. R. Gunzel-Apel, T. Leeb: A noncoding melanophilin gene (MLPH) SNP at the splice donor of exon 1 represents a candidate causal mutation for coat color dilution in dogs. In: J Hered. 2007.][Samantha L. van Buren, Katie L. Minor et al.: A Third MLPH Variant Causing Coat Color Dilution in Dogs. In: Genes, Vol. 11, Issue 6, June 2020.]
Every dog has two - one from the sire and one from the dam. The gene expression depends on the genotype:
-
DD: Both sire and dam have inherited the wild type allele. The coat is not lightened.
-
Dd: Either sire or dam have inherited the allele for dilution. However, the dilution of colour is not visible in the phenotype - the dog has the same coat colour as a DD dog.
-
dd: Sire and dam have inherited the allele for the dilute colour expression. The black areas of the coat are lightened to blue, dogs additionally lightened by the gene on the B locus take on the colour typical of the Weimaraner.
According to the Mendelian Rules, an average of 25% of the puppies receive the homozygous gene combination dd if both parents are .
Horses
-
Equine coat color genetics discusses color genes in , including a brief description of dilution genes
-
Equine coat color describes various colors in horses
-
Cream gene, describes the process for horses by which the cremello, perlino, smoky cream double-dilute colors are created as well as the buckskin, palomino and smoky black single dilute colors.
-
Dun gene describes another common dilution gene in horses
-
Champagne gene, describes a different dilution gene in horses that also creates cream coloring, pale skin with mottling and light-colored eyes.
-
Pearl gene, also called the "Barlink factor", is a recessive gene. One copy of the allele has no effect on the coat color of black, bay or chestnut horses. Two copies on a chestnut horse produce a pale, uniform apricot color of body hair, mane and tail as well as pale skin. It also interacts with Cream dilution to produce "pseudo-double" Cream dilutes with pale skin and blue or green eyes.
-
Silver Dapple Gene lightens black hair, such as the mane and tail of a bay horse
-
Mushroom (horse) describes an unknown and unmapped theorized dilution gene dilutes red pigment in body color to a pale beige color.
See also
.jpg/){kind=link}
 in Silver Labrador dog.jpg/){kind=link}