Degrees of Annotation

"Annotation" has various definitions. One of them (from wikipedia) is - Annotation is information associated with a particular point [or item] in a document or other piece of information.

In the context of the bio* domain, annotation referes to some descriptive text that assists in the interpretation of the primary information [about an item] at hand. There can be various levels of annotation for example:

• If the sequence trace coming out of a sequencer is the primary information then the assignment of "labels" such as 'start site', 'exon', 'intron' to different parts of the sequence is an annotation.

• At the second level this annotation itself [the statement about the boundries of 'start site', 'exon', 'intron'] is a conceptual item called a gene. Which is further "annotated" to have a particular 'function' or 'location' in the cell.

• At a still higher level this annotation [about the function or location] is an item that is "annotated" to be relevant only in a certain genetic or experimental context.

so defining the boundry between an information item (or data) and an annotation is dependent on the use case.