Question

Which one of the following represents a palindromic sequence in DNA?

• A. 5'- GAATTC-3'
  3'-CTTAAG-5'
• B. 5' - CCAATG - 3'
  3' - CAATCC - 5'
• C. 5' -CATTAG-3'
  3'-GATAAC-5'
• D. 5' - GATACC - 3'
  3' - CCTAAG - 5'

Answer 1

The correct option is A 5'- GAATTC-3'

3'-CTTAAG-5'
A palindromic sequence is a sequence of nucleic acids that is the same when read from 5' to 3' on one strand and 5' to 3' on the other complementary strand.
5' - GAATTC-3' and 3' - CTTAAG-5' sequences read the same on the two strand in 5'$\to$3' direction. This is also true in the 3'$\to$5' direction. Hence, it is a palindromic sequence in DNA.