Frayed Ends
Across from each single strand of DNA, we typically see adenine pair with thymine, and cytosine pair with guanine to form a parallel complementary strand as described below. Two nucleotide sequences which correspond to each other in this manner are referred to as complementary:
5'-ATCTGACT-3' 3'-TAGACTGA-5'A frayed end refers to a region of a double stranded (or other multi-stranded) DNA molecule near the end with a significant proportion of non-complementary sequences; that is, a sequence where nucleotides on the adjacent strands do not match up correctly:
5'-ATCTGACTAGGCA-3' 3'-TAGACTGACTACG-5'The term "frayed" is used because the incorrectly matched nucleotides tend to avoid bonding, thus appearing similar to the strands in a fraying piece of rope.
Although non-complementary sequences are also possible in the middle of double stranded DNA, mismatched regions away from the ends are not referred to as "frayed".
Read more about this topic: Sticky And Blunt Ends, Variations in Double-stranded Molecules
Famous quotes containing the word ends:
“A third variety of drama ... begins as tragedy with scraps of fun in it ... and ends in comedy without mirth in it, the place of mirth being taken by a more or less bitter and critical irony.”
—George Bernard Shaw (1856–1950)