The representation of the genotypes is as follows:
Homozygous dominant for curly hair (James): CC
Heterozygous dominant for curly hair (wife): Cc
The curly or straight hairs are the phenotypes and CC or Cc is the genotype of parental alleles.
When the first child is born which means the F1 generation, the type of hair the child will have can be predicted by punnet squares. The Punnet squares have been shown in the image.
From the above punnet squares, two out of four probable phenotype or genotype of curly hair is 2/4 = 1/2 or 50%, have CC as their genotype and are homozygous dominant for curly hairs.
