Symbol | Meaning | Origin of designation |
---|---|---|
a | a | adenine |
g | g | guanine |
c | c | cytosine |
t | t | thymine |
u | u | uracil |
r | g or a | purine |
y | t/u or c | pyrimidine |
m | a or c | amino |
k |
g or t/u
|
keto |
s | g or c | strong interactions 3H-bonds |
w | a or t/u | weak interactions 2H-bonds |
b | g or c or t/u |
not a |
d
|
a or g or t/u |
not c |
h | a or c or t/u |
not g |
v | a or g or c |
not t, not u |
n | a or g or c or t/u, unknown, or other |
any |