Dilution gene

There are many examples of such genes: Diluted coat colors have melanocytes, but vary from darker colors due to the concentration or type of these pigment-producing cells, not their absence.

In dogs, a mutation of the MLPH locus known as the dilute gene causes eumelanin to lighten while pheomelanin remains almost unchanged.

[2][3] Of the colour shades found in the coat of dogs, the light brown caused by pheomelanin is hardly affected.

Chocolate brown eumelanine is lightened to the typical colour of the Weimaraner.

The gene expression depends on the genotype: According to the Mendelian Rules, an average of 25% of the puppies receive the homozygous gene combination dd if both parents are genetic carriers.