Question

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. 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. The two students who have two fragments have two restriction sites within this gene.b. The students with three fragments are said to have "fragile sites."c. Each of these students is heterozygous for this gene.d. Each pair of students has a different gene for this function.e. The two students who have two fragments have one restriction site in this region.

Answer 1

e. The two students who have two fragments have one restriction site in this region.

Step-by-step explanation:

Restriction enzymes are endonucleases and cut the DNA at restriction sites. Restriction sites are the specific DNA sequences and are unique for each restriction enzyme. A restriction enzyme can cut the DNA molecule only if the DNA has its restriction site. Therefore, the presence of zero restriction sites in the gene of interest would not allow the selected restriction enzyme to digest this piece of DNA and the DNA will remain intact.

On the other hand, the presence of one restriction site in the gene of interest would allow the restriction enzyme to make a single cut in the DNA. Therefore, two DNA fragments would be obtained.