If a mutation removes a restriction site what can happen to the fragment pattern?

Correct answer: One cut may be lost

A restriction enzyme cuts DNA only when it finds its specific recognition sequence, called a restriction site. If a mutation changes that sequence, the enzyme may no longer recognize it. The cut that normally occurred at that position is then absent. As a result, two neighboring fragments may remain joined and form one larger fragment. Therefore, option A, “one cut may be lost,” is correct. The word “may” is important because the exact effect depends on whether the mutation truly destroys recognition and on the enzyme’s sequence requirements.

For example, if a DNA molecule normally has three sites for an enzyme, it may produce four fragments when the molecule is linear. Removing one site can reduce the number of cuts to two and may produce three fragments, with one fragment larger than before. The mutation does not make the enzyme double, convert DNA into RNA, or determine a green gel color. Thus, the supplied answer correctly describes the likely change in the fragment pattern.