SAT Subject Biology Practice Question 170: Answer and Explanation
20. A female chimpanzee recently gave birth to an infant while in captivity. Because the paternity of the infant is unclear, scientists tested the DNA from two male chimpanzees, along with the female and infant. The resulting electrophoresis gel is shown.
Based on the gel electrophoresis result, what can be concluded?
I. Male 1 could possibly be the parent.
II. Male 1 can be ruled out as the parent.
III. Male 2 could possibly be the parent.
IV. Male 2 can be ruled out as the parent.
A. II only
B. I and III
C. I and IV
D. II and III
E. II and IV
Correct Answer: D
Male 1 lacks band 1, band 3, and the band just beneath band 2 in the infant's lane. Since the infant must have received the corresponding DNA from its father, this allows Male 1 to be ruled out. The lane for Male 2 contains these bands, so Male 2 could possibly be the father.