First the possible gametes of the two parents are aligned along two sides of a square.

Then the gametes are combined to show genotypes of potential zygotes in the cells of the square.

• All the eggs of homozygous recessive (albino) mother have the recessive allele (m).

• All the sperm of homozygous dominant (pigmented) father have the dominant allele (M).

• All the offspring are heterozygous (Mm) in genotype, pigmented in phenotype.

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