When DNA molecule “A” is cut with the restriction enzyme EcoRI, it is cut into four pieces. When DNA molecule “B,” which is exactly identical to DNA molecule “A” except for the presence of one SNP, is cut with EcoRI, it is cut into three pieces. What is the best explanation for this observation?
A. The SNP occurs in all EcoRI restriction sites in DNA molecule “B.”
B. The SNP occurs in a single EcoRI restriction site in DNA molecule “B.”
C. Not enough EcoRI was used to cut DNA molecule “B.”
D. An excess of EcoRI was used to cut DNA molecule “A.”
Answer:B
When DNA molecule “A” is cut with the restriction enzyme EcoRI, it is cut into four pieces. When DNA molecule “B,” which is exactly identical to DNA molecule “A” except for the presence of one SNP, is cut with EcoRI, it is cut into three pieces. What is the best explanation for this observation?
A. The SNP occurs in all EcoRI restriction sites in DNA molecule “B.” B. The SNP occurs in a single EcoRI restriction site in DNA molecule “B.” C. Not enough EcoRI was used to cut DNA molecule “B.” D. An excess of EcoRI was used to cut DNA molecule “A.”