Question

Genomic DNA is digested with Alu $I$, a restriction enzyme which is a four base - pair cutter. What is the frequency with which it will cut the DNA assuming a random distribution of bases in the genome?

• A. $1/4$
• B. $1/24$
• C. $1/256$
• D. $1/1296$

Answer 1

Answer: (C)

$1/256$

Alu I is a restriction endonuclease which is a four base-pair cutter. There are total of 4 nucleotide bases. The frequency of the base cutter can be calculated as 1/4${}^4$= 1/256. This means there are 1/256 chances that the enzyme can cut the four base pair sequence in the DNA sequences composed of the four bases.

Thus, the correct answer is option C.