--------------------------------------------------------------------------------

Feature Key           tRNA

Definition            成熟转录RNA，一个小的RNA分子（75-85碱基长），通过它实现核酸序列到氨基酸序列的翻译

Optional qualifiers   /anticodon=(pos:<base_range>,aa:<amino_acid>)
                      /citation=[number]
                      /db_xref="<database>:<identifier>"                     
                      /evidence=<evidence_value>
                      /function="text"
                      /gene="text"
                      /label=feature_label
                      /map="text"
                      /note="text"
                      /partial
                      /product="text"
                      /pseudo
                      /standard_name="text"
                      /usedin=accnum:feature_label

--------------------------------------------------------------------------------

Feature Key           unsure

Definition            作者对在这段区域存在的其它序列不确定

Optional qualifiers   /citation=[number]
                      /db_xref="<database>:<identifier>"
                      /evidence=<evidence_value>                     
                      /gene="text"
                      /label=feature_label
                      /map="text"
                      /note="text"
                      /replace="text"
                      /usedin=accnum:feature_label

--------------------------------------------------------------------------------

Feature Key           V_region
 

Definition          免疫球蛋白的重链和轻链以及T细胞受体α、β、γ链的可变区域。编码可变的氨基端部分。由V_segments,D_segments,N_segments和J_segments组成

Optional qualifiers   /citation=[number]
                      /db_xref="<database>:<identifier>"
                      /evidence=<evidence_value>
                      /gene="text"
                      /label=feature_label
                      /map="text"
                      /note="text"
                      /partial
                      /product="text"
                      /pseudo
                      /standard_name="text"
                      /usedin=accnum:feature_label

Parent Key            CDS

Organism scope        Eukaryotes

--------------------------------------------------------------------------------

Feature Key           V_segment

Definition            免疫球蛋白的重链和轻链以及T细胞受体的α、β、γ链的可变片段。编码V区的大部分和前导肽的最后几个氨基酸

Optional qualifiers   /citation=[number]
                      /db_xref="<database>:<identifier>"
                      /evidence=<evidence_value>
                      /gene="text"
                      /label=feature_label
                      /map="text"
                      /note="text"
                      /partial
                      /product="text"
                      /pseudo
                      /standard_name="text"
                      /usedin=accnum:feature_label

Parent Key            CDS

Organism scope        Eukaryotes

--------------------------------------------------------------------------------

Feature Key           variation

Definition           相关的特征包含在同一基因的稳定的突变（例如：RFLPs,多态性等），不同于在此位置的其它序列

 
Optional qualifiers   /allele="text"
                      /citation=[number]
                      /db_xref="<database>:<identifier>"
                      /evidence=<evidence_value>                     
                      /frequency="text"
                      /gene="text"
                      /label=feature_label
                      /map="text"
                      /note="text"
                      /partial
                      /phenotype="text"
                      /product="text"
                      /replace="text"
                      /standard_name="text"
                      /usedin=accnum:feature_label