Use the following information to answer the next few questions.
A group of six students has taken samples of their own cheek cells, purified the DNA, and used a restriction enzyme known to cut at zero, one, or two sites in a particular gene of interest.

1. Why might they be conducting such an experiment?
A) to find the location of this gene in the human genome
B) to prepare to isolate the chromosome on which the gene of interest is found
C) to find which of the students has which alleles
D) to collect population data that can be used to assess natural selection
E) to collect population data that can be used to study genetic drift

2. Their next two steps, in order, should be
A) use of a fluorescent probe for the gene sequence, then electrophoresis.
B) electrophoresis of the fragments followed by autoradiography.
C) electrophoresis of the fragments, followed by the use of a probe.
D) use of a ligase that will anneal the pieces, followed by Southern blotting.
E) use of reverse transcriptase to make cDNA, followed by electrophoresis.

3. Analysis of the data obtained shows that two students each have two fragments, two students each have three fragments, and two students each have one only. What does this demonstrate?
A) Each pair of students has a different gene for this function.
B) The two students who have two fragments have one restriction site in this region.
C) The two students who have two fragments have two restriction sites within this gene.
D) The students with three fragments are said to have "fragile sites."
E) Each of these students is heterozygous for this gene.