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Given below is a sample of a portion of DNA strand giving the base sequence on the opposite strands. What is so special shown in it?
5′ ______ GAATTC ______ 3′
3′ ______ CTTAAG ______ 5′
5′ ______ GAATTC ______ 3′
3′ ______ CTTAAG ______ 5′
A
Palindromic sequence of base pairs
B
Replication completed
C
Deletion mutation
D
Start codon at the 5′ end
Detailed Solution
A palindromic sequence in DNA is a sequence of base pairs that reads the same on the two strands when the orientation of reading is kept the same.
Reading the upper strand in the 5′ → 3′ direction gives GAATTC.
Reading the lower strand in the 5′ → 3′ direction also gives GAATTC.
So the given sequence is a palindrome; it is the recognition sequence of the restriction endonuclease EcoRI, which cuts between G and A on each strand to produce sticky ends.
Nothing in the sequence shows replication, a deletion or a start codon (AUG/ATG).
Hence it shows a palindromic sequence of base pairs.
Reading the upper strand in the 5′ → 3′ direction gives GAATTC.
Reading the lower strand in the 5′ → 3′ direction also gives GAATTC.
So the given sequence is a palindrome; it is the recognition sequence of the restriction endonuclease EcoRI, which cuts between G and A on each strand to produce sticky ends.
Nothing in the sequence shows replication, a deletion or a start codon (AUG/ATG).
Hence it shows a palindromic sequence of base pairs.