upstream

The region extending in a 5' direction from a gene.

1. The stretch of DNA lying in the 5' direction from the site being considered. Where the reference point is the initiation of transcription, the first transcribed base is designated +1 and upstream nucleotides are marked with minus signs, e.g. -1, -10; 2. In chemical engineering, those phases of a manufacturing process that precede the biotransformation step. Refers to the preparation of raw materials for a fermentation process. Also called upstream processing.

Towards the source of flow, or located in the area from which the flow is coming.

In tracing, upstream is the direction along the arcs that is against the direction of flow. Direction of flow is determined by a user-defined convention. See directed network.

The direction opposite the data flow. 2. With respect to the flow of data in a communications path: at a specified point, the direction toward which data are received earlier than at the specified point.