Question

Jenna is trying to construct a pedigree for the occurrence of red hair in her family. She has two sisters (one older and one younger), and Jenna is the only one in her family who has red hair. What will be components of Jenna's pedigree?
Select one:

a. a line connecting her mother and father, and three colored squares representing Jenna and her sisters
b. one colored circle, three empty circles, and one empty square all in a line, representing Jenna, her mother and sisters, and her father, respectively
c. a line connecting her mother and father, and three colored circles representing Jenna and her sisters
d. a line connecting her mother and father, and a colored circled on the left side beneath Jenna's parents, representing her youngest sister
e. a line connecting her mother and father, a colored circle representing Jenna, and two empty circles representing her sisters

Answer 1

Answer: a line connecting her mother and father, a colored circle representing Jenna, and two empty circles representing her sisters

Explanation: Jenna's red hair can be determined by incomplete dominance.

Incomplete dominance is a condition where neither of the alleles responsible for a trait is dominant.

In incomplete dominance, one allele for a specific trait is not completely expressed over its paired allele. So, if an organism is heterozygous for a trait, it shows a third phenotype.