Punnet Square Practice Lesson 5 Punnet Square Practice

E e Father Practice Problem 1 - Part 1 Earlobes have two forms. Unattached earlobes are dominant (E). Attached earlobes are recessive (e). The father is heterozygous. Question: What is his genotype? Answer: His genotype is Ee because he is heterozygous. E Father e

e e E e Mother Mother Father Practice Problem 1 - Part 2 Earlobes have two forms. Unattached earlobes are dominant (E). Attached earlobes are recessive (e). Question: If the mother has attached earlobes, what is her genotype? Mother Mother e e E Father Answer: Her genotype must be ee because attached earlobes are recessive. e

e e E E e E e e e e e e Mother Father Practice Problem 1 - Part 3 So the father is heterozygous (Ee) The mother is homozygous dominant (ee). Question: What are the chances that their offspring will have attached earlobes? Mother e e Answer: There is a 50% chance because there are two boxes with the ee genotype. E Father E e E e e e e e e

D D d D d D d d D d D d Mother Father Practice Problem 2 Dimples are a dominant trait (D) Not having dimples is the recessive trait (d). A mother is homozygous dominant (DD) The father is homozygous recessive (dd). Question: What are the chances they have children with dimples. Mother D D Answer: 100% will have dimples because all possible children carry at least one dominant allele. d Father D d D d d D d D d

Practice Problem 3 Freckles (F) are a dominant trait. Not having freckles is a recessive trait (f). Question: If mother is a heterozygous and a father is a homozygous recessive, what are the chances that their offspring will have freckles? Mother F f Answer: There is a 50% chance that their offspring will have freckles because the dominant allele appears half the time. f F f f f f F f f f