The entries in the database are structured so as to be usable by human readers as well as by computer programs. The explanations, descriptions, classifications and other comments are in ordinary English, and the symbols and formatting employed for the base sequences themselves have been chosen for readability. Wherever possible, symbols familiar to molecular biologists have been used. At the same time, the structure is systematic enough to allow computer programs easily to read, identify, and manipulate the various types of data included. Each entry in the database is composed of lines. Different types of lines, each with its own format, are used to record the various types of data which make up the entry. In general, fixed format items have been kept to a minimum, and a more syntax-oriented structure adopted for the lines. The two exceptions to this are the sequence data lines and the feature table lines, for which a fixed format was felt to offer significant advantages to the user. Users who write programs to process the database entries should not make any assumptions about the column placement of items on lines other than these two: all other line types are free-format.
Note that each line begins with a two-character line code, which indicates the type of information contained in the line. The currently used line types, along with their respective line codes, are listed below:
Note that some entries will not contain all of the line types, and some line types occur many times in a single entry. As indicated, each entry begins with an identification line (ID) and ends with a terminator line (//). The various line types appear in entries in the order in which they are listed above (except for XX lines which may appear anywhere between the ID and SQ lines). A detailed description of each line type is given in the following sections.
ID X56734; SV 1; linear; mRNA; STD; PLN; 1859 BP.
XX
AC X56734; S46826;
XX
DT 12-SEP-1991 (Rel. 29, Created)
DT 25-NOV-2005 (Rel. 85, Last updated, Version 11)
XX
DE Trifolium repens mRNA for non-cyanogenic beta-glucosidase