Complementarity (molecular biology)

From Wikipedia, the free encyclopedia

For complementation and complementation tests used in genetics research, see Complementation (genetics).
For other uses, see complement.
On the left: nucleotides that form the DNA and their complementary. Between A and T there are two hydrogen bonds, while 3 are between C and G. On the right a DNA sequence and its complementary strand.
On the left: nucleotides that form the DNA and their complementary. Between A and T there are two hydrogen bonds, 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 remember this is

A      Gwinnett
Tlanta County

tRNAs exhibit wobble, in which the third base of their anticodon does not follow the strict complementarity rules.

[edit] See also