在我们查阅文献或做分析时经常会看见除A/G/C/T以外的符号用来代表一类碱基，现在将DNA、RNA水平下的标准命名总结如下：
DNA水平
| 符号 | 含义 | 描述 |
|---|---|---|
| A | A | Adenine， 腺嘌呤 |
| C | C | Cytosine， 胞嘧啶 |
| G | G | Guanine， 鸟嘌呤 |
| T | T | Thymine， 胸腺嘧啶 |
| B | C/ G / T | not-A (B follows A in alphabet) |
| D | A / G / T | not-C (D follows C in alphabet) |
| H | A / C / T | not-G (H follows G in alphabet) |
| K | G / T | Keto， 酮类 |
| M | A / C | aMino， 胺基 |
| N | A / C / G / T | aNy，任意的 |
| R | A / G | puRine，嘌呤类 |
| S | G / C | Strong interaction (3 H-bonds) |
| V | A / C / G | not-T / not-U ( V follows U ) |
| W | A / T | Weak interaction (2 H-bonds) |
| Y | C / T | pYrimidine， 嘧啶 |
| X* | A / C / G / T | masked nucleotide |
| -* | none | gap of indeterminate length |
RNA水平
| 符号 | 含义 | 描述 |
|---|---|---|
| a | A | Adenosine， 腺甘酸 |
| c | C | Cytidine， 胞嘧啶核苷 |
| g | G | Guanosine， 鸟嘌呤核苷 |
| u | U | Uridine， 尿嘧啶核苷 |
| b | c / g / u | not-a (b follows a in alphabet) |
| d | a / g / u | not-c (d follows c in alphabet) |
| h | a / c / u | not-g (h follows g in alphabet) |
| k | g / u | keto， 酮类 |
| m | a / c | amino， 胺基 |
| n | a / c / g / u | any，任意 |
| r | a / g | purine， 嘌呤 |
| s | g / c | strong interaction (3 H-bonds) |
| v | a / c / g | not-u ( v follows u |
| w | a / u | weak interaction (2 H-bonds) |
| y | c / u | pyrimidine |
参考资料：
1.http://varnomen.hgvs.org/bg-material/standards/
