PRIMARY line shows the sequence spans of the primary entries that contribute to the TPA or TSA sequence.

An example of PRIMARY block in DDBJ flat file of TPA entry

example
PRIMARY     TPA_SPAN            PRIMARY_IDENTIFIER PRIMARY_SPAN        COMP
            1-1000              ZZ000001.1         50001-51000
            101-200             ZZ000003.1         1-100
            501-600             ZZ000003.1         101-200
            901-2000            ZZ000002.1         25001-26100         c
            1451-1550           ZZ000003.1         201-300

1-1000－－The span of TPA sequence corresponding to the cited sequence

ZZ000001.1－－The accession number with version of the cited primary entry

50001-51000－－The cited span of the primary entry

c－－It shows that the complementary sequence of the primary entry is cited

Schematic diagram of the alignment between TPA and primary entries on the example shown above