Biology Ser2 Activity 3.3.1 Inheritance in Action

Imagine that you are a doctor in a maternity ward. During your last shift, 20 babies were born. 10 had blue eyes, and 10 had brown eyes. Remember genotypes are the two alleles given for each trait, written with a

letter. For this activity brown eyes bw blue eyes. Phenotypes are the physical appearance of the trait.

Given the phenotypes, what are the possible genotypes for these babies?

A dominant phenotype can be described as a trait whose alleles masks the effect of the alleles of the recessive trait. A person can have a genotype, either dominant homozygous or heterozygous, for that trait. In the above scenario, either the blue or brown trait would be dominant over the other. The babies showing dominant genotype might be heterozygous or homozygous for the dominant trait.

The babies carrying two recessive alleles will have the recessive colour.