A gene mutation = knockdown or knockout

[steelcat]

A gene mutation = knockdown or knockout or both?

[canalon]

Both or neither or something else, but not both at the same time...

[jonmoulton]

Where a gene is altered to lose its function, this is a knockout.

Where a gene is altered to decrease its expression, this is a knockdown.

Knockdown is also used to describe RNA-level manipulations to decrease gene expression, such as siRNA or antisense treatments. Unlike gene modifications, treatments with oligos have temporary effects. However, stable expression of antisense or siRNA from a plasmid (or from stably integrated DNA) can have long-term effects.