Terminology

Assay

An assay is an investigative (analytic) procedure for qualitatively assessing or quantitatively measuring the presence, amount, or functional activity of a target entity.

The measured entity is often called the analyte, the measurand, or the target of the assay.

Transfection

The process of deliberately introducing naked or purified nucleic acids into eukaryotic cells.

Transformation

Used to describe non-viral DNA transfer in bacteria and non-animal eukaryotic cells, including plant cells.

In animal cells, transfection is the preferred term, as the term "transformation" is also used to refer to a cell's progression to a cancerous state (carcinogenesis).

Transduction

Used to describe virus-mediated gene transfer into prokaryotic cells.