Nucleic Acid Nomenclature - Expanded Letter Code

Expanded Letter Code

In addition to the conventional GATC symbols, there is an expanded letter code to indicate a position within a sequence that may be flexible when defining sequences.

Letter Nucleotide(s) included
A A
T T
G G
C C
R G or A
Y T or C
M A or C
K G or T
S G or C
W A or T
H A or C or T
B G or T or C
V G or C or A
D G or T or A
N G or T or A or C

For example, if the sequences known to bind protein X are known to be AAAAAAGAAA, AAAAAACAAA, AAAAAATAAA, and AAAAAAAAAA, this can be expressed as AAAAAANAAA.

Read more about this topic:  Nucleic Acid Nomenclature

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