Ques. 1NEET (UG) 2020
The specific palindromic sequence which is recognized by EcoRI is
- 5′ - GGATCC - 3′ 3′ - CCTAGG - 5′
- 5′ - GAATTC - 3′ 3′ - CTTAAG - 5′
- 5′ - GGAACC - 3′ 3′ - CCTTGG - 5′
- 5′ - CTTAAG - 3′ 3′ - GAATTC - 5′
Answer
(2) 5′ - GAATTC - 3′ 3′ - CTTAAG - 5′
Solution
A palindromic sequence reads the same on the two strands when both are read in the same orientation (5' 3').
As per NCERT, the recognition sequence of EcoRI is:
5′ - GAATTC - 3′
3′ - CTTAAG - 5′
∵ Upper strand (5' 3') = GAATTC and lower strand read 5' 3' = GAATTC (same)
Option (1) (GGATCC) is the site of BamHI; options (3) and (4) do not match EcoRI.
Answer: (2)