Question

Find the correct palindromic sequence for the given DNA segment. 5'ATTGCAAT3'

Answer 1

The palindromic sequence is the nucleotide sequence in which one strand is the same as its reverse complementary strand. A nucleotide sequence is considered as a palindrome only if its complementary strand reads the same in the opposite direction.

Complete answer:
The DNA sequence 5'ATTGCAAT3' is a palindromic sequence as its nucleotide-by-nucleotide complementary sequence is 3'TAACGTTA5'. Upon reversing the order of these nucleotides in the complementary sequence, gives the original sequence.
5' – A T T G C A A T – 3'
3' – T A A C G T T A – 5'
A palindromic sequence is a sequence of nucleic acids in a double-stranded DNA or RNA molecule. It reads in a specific direction (e.g. 5' to 3') on one strand and matches the sequence in the same direction (e.g. 5' to 3') on the complementary strand.
A double helix is formed by two paired anti-parallel strands of nucleotides running in opposite directions, and the nucleotides pair in their usual way, i.e. adenine (A) with thymine (T) in DNA or uracil (U) in RNA and cytosine (C) with guanine (G). A single-stranded nucleotide sequence is a palindrome only if it is equal to its reverse complement.

So, the correct answer is option B.

Additional Information:
A Palindromic sequence plays a vital role in molecular biology and genetics. Restriction endonucleases or restriction enzymes recognize specific palindromic sequences and cut them to produce sticky ends.
The restriction enzyme EcoR1 recognizes the following palindromic sequence:
5'- G A A T T C -3'
3'- C T T A A G -5'

Note: Palindromic sequences can also possess methylation sites. These sites are where a methyl group is attached to a palindromic sequence. The process of methylation makes the resistant gene inactive; this process is known as insertional inactivation or insertional mutagenesis.