1. Albinism is a trait found in many species which reduces or eliminates pigmentation in
skin, hair, and eyes. Albinism is inherited as a recessive trait (only those with aa -
homozygous recessive) will show the features of Albinism. (provide percentages and
show your work)
a. if two heterozygous individuals reproduce, what are the chances they will have
an albino child?
b. if one of their children is homozygous recessive, and grows up to marry and have
children with another albino, what are the chances they can have a child who is
c. Imagine a community where people discriminate against albino individuals, and
force them to move into their own village, and only marry one another. Would
this be a sure way to eliminate albinism in the community? Why or why not?
d. Continuing with the imaginary community above, what do you think would
happen to the total number of albino individuals in the population (both
villages)? Would it increase, or decrease? Explain.
e. Which of the four evolutionary forces is at work here? Could there be more than
2. Two individuals are heterozygous for Sickle Cell Anemia (AS) they live in an area where malaria is
common. They have three children together and are preparing for the birth of their fourth. Two
of their children have normal hemoglobin (AA), and one has Sickle Cell Anemia (SS), and is
What are the chances that their next child will be born with Sickle Cell Anemia
(SS)? Explain your answer.
b. One of the children with normal hemoglobin grows up to marry someone who is
heterozygous for the trait (AS). What are the chances that one of THEIR children will be
able to survive a future outbreak of malaria? Show your work.
Why do some populations have a relatively high frequency of the sickle cell trait, even
when they do not live in areas that have much risk of malaria (like for example, the
African American population in the United States). What genetic/evolutionary force can