For complementation and complementation tests used in genetics research, see Complementation (genetics).
On the left: nucleotides that forms the DNA and their complementary. Between A and T there are 2 hydrogen bounds, while 3 are between C and G. On the right a DNA sequence and its complementary strand.
In molecular biology, complementarity is a property of double-stranded nucleic acids such as DNA and RNA as well as DNA:RNA duplexes. Each strand is complementary to the other in that the base pairs between them are non-covalently connected via two or three hydrogen bonds. Since there is only one complementary base for any of the bases found in DNA and in RNA, one can reconstruct a complementary strand for any single strand. This is essential for DNA replication. For example, the complementary strand of the DNA sequence
A G T C A T G
is
T C A G T A C
a trick to remeber this is
A Gwinnett Tlanta County
tRNAs exhibit wobble, in which the third base of their anticodon does not follow the strict complementarity rules.
