There are two genes that determine the coat colour expression in dogs: eumelanin and merle. These genes are located on two separate chromosomes. For the eumelanin gene, black coat colour (E) is dominant over red coat colour (e). The merle gene controls the degree to which these coat colours are expressed through incomplete dominance. The following table describes the merle gene expression. Genotype Phenotype MM - white Mm - half color grey or light red mm - full color black or red 1. If a dog breeder wants to determine the unknown genotype of a dog, what colour of dog must she use as a testcross? (1 mark) 2. A white dog was testcrossed, and all of the puppies had light red coats. What is the genotype of the white dog? Use a Punnett square to show your work. (2 marks)