Each nucleotide in a double stranded DNA molecule is paired with its Watson-Crick counterpart. This counterpart is called its complementary nucleotide.
Double stranded DNA sequences are represented by the upper (sense) strand sequence going in the direction from its 5′- to 3′-end. The complementary sequence is thus the sequence of the lower (antisense) strand in the same direction as the upper strand. The reverse sequence is the sequence of the upper strand in the direction from its 3′- to its 5′-end. The reverse complement sequence is the sequence of the lower strand in the direction of its 5′- to its 3′-end.
Example:
Original sequence: ACGTATAGGCTGACACGTAGAGATGGATGACCATAG
Reverse sequence: GATACCAGTAGGTAGAGATGCACAGTCGGATATGCA
Complement sequence: TGCATATCCGACTGTGCATCTCTACCTACTGGTATC
Reverse complement: CTATGGTCATCCATCTCTACGTGTCAGCCTATACGT
List of all complement nucleotides:
| Base | Name / Bases | Complementary Base |
|---|---|---|
| A | Adenine | T |
| C | Cytidine | G |
| G | Guanidine | C |
| T | Thymidine | A |
| Y | Pyrimidine (CT) | R |
| R | Purine (AG) | Y |
| S | Strong (GC) | S |
| W | Weak (AT) | W |
| K | Keto (TG) | M |
| M | Amino (AC) | K |
| B | not A (CGT) | V |
| D | not C (AGT) | H |
| H | not G (ACT) | D |
| V | not T (ACG) | B |
| N | Unknown (ACGT) | N |
Uridine (U) is the replacement for Thymidine (T) in RNA. Any entered U are automatically converted into T.
See the Tutorial on how to create reverse complement sequence.
