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Question
Which of the following DNA sequences qualifies is designated as a palindrome?
Options
5' - CACCAG - 3' in one strand
3' - GACCAG - 5' in one strand
5' - GACGAG - 3' 3' - CTGGTC - 5'
5' - AGCGCT - 3' 3' - TCGCGA - 5'
Solution
5' - CACCAG - 3' in one strand
Explanation:
A palindromic sequence is one that consists of nucleic acids within a double helix of DNA or RNA that is the same when read from 5' to 3' on one strand and 5' to 3' on the complementary strand. It is sometimes referred to as a palindrome or inverted-reverse sequence. The complementary pairing of nucleotides within the DNA double-helix consists of Adenine (A) partnering with either Thymine (T) in DNA or Uracil (U) in RNA, while Cytosine (C) pairs with Guanine (G). If a sequence is palindromic, the nucleotide sequence of one strand is the same as that of its reverse complementary strand. The restriction endonuclease attaches to a specific cleavage site and cleaves it. When the complementary strand is read backwards, the sequence is 5' - CACCAG - 3', which is identical to the previous one, indicating that the sequence is palindromic.