Question

The restriction endonuclease EcoR-I recognizes and cleaves DNA sequence as shown below

 5' -G A A T T C-3' 

 3' -C T T A A G-5' 

 What is the probable number of cleavage sites that can occur in a 10 kb long random DNA sequence ?

(A) 10 

(B) 2 

(C) 100 

(D) 50 

Answer 1

Correct Option :- (B) 2

Explanation :-

Eco RI is an example of six-cutter restriction endonuclease. It usually cleaves once in every 4096 bp.

(1/4)⁶ = 1/4096

Given length of DNA fragment= 10 Kb = 10000 bp Hence, 

Probable no. of cleaving sites = 10000/4096 = 2.44