Question

In human beings, curly hair is incompletely dominant over straight hair, such that heterozygous individuals have wavy hair. In the following crosses, in which the phenotypes of the parents are given, what are the gametes produced by each parent, and what will be the hair textures of the potential offspring? Use Punnett squares as part of your answers.

Answer 1

A genetic cross involves two parents for a specific trait, such as the hair trait. The gene has variations called alleles. In one gene, one allele is dominant over the other. The complete dominant allele can be found in both purebred and heterozygous forms and suppresses the recessive character. Here, the curly hair is incomplete dominant over the straight. Wavy hair is produced in heterozygous states; this is an example of incomplete dominance.

When both HH' parents are crossed, then each parent will form the H and H' gametes. Out of the three offspring, one curly, two wavy, and one straight will be formed. The punnet square is explained below in the image.

Hence, when two people with wavy hair are crossed, three types of offspring are formed, such as those with curly, wavy, and straight hair. The genotype and phenotype ratio is 1:2:1.

Step-by-step explanation: