Concept:A palindromic recognition sequence in double-stranded DNA reads identically on both antiparallel strands when read in the \( 5' \rightarrow 3' \) direction.
Solution:Reading the top strand \( 5' \rightarrow 3' \) gives
GAATTC, and reading the bottom strand \( 5' \rightarrow 3' \) also gives
GAATTC. This sequence is the specific palindromic cleavage site recognized by the restriction enzyme
EcoRI.
Why other options are incorrect:- Option A: \( 5' \text{-CCAATG-} 3' \) read in reverse on the complementary strand gives \( 5' \text{-CCTAAG-} 3' \), which is not identical.
- Option C: \( 5' \text{-CATTAG-} 3' \) read in reverse on the complementary strand yields \( 5' \text{-CAATAG-} 3' \), which fails palindromic symmetry.
- Option D: \( 5' \text{-GATACC-} 3' \) read in reverse on the complementary strand yields \( 5' \text{-GAATCC-} 3' \), which is non-palindromic.
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