Learning more from knockdowns and knockouts

Morpholino knockdowns and engineering null mutants provide complementary techniques to explore gene function. Compared to a wild-type organism, a null mutant reveals a change due to the chronic loss of a protein, in which genetic compensation might be altering the transcription of related genes. A Morpholino knockdown shows the change due to the acute loss of a protein, a loss in an uncompensated background of transcripts. The outcome of the acute protein loss from Morpholino knockdown is often a more extreme phenotype than seen in the chronic loss of protein expression in null mutants.

A null mutant provides an opportunity to control for the specificity of a corresponding Morpholino by treating the null mutant with a Morpholino targeting that null gene. If the outcome is identical to the untreated mutant, this show that the Morpholino is not causing discernable off-target effects. Next, treat a wild type organism with the Morpholino. The difference between the mutant phenotype and the Morpholino phenotype is due to the loss of protein in a compensated background (mutant) versus an uncompensated background (Morpholino).