 A cause for concern in the use of Morpholinos is the potential for " off @-@ target " effects . Whether an observed morphant phenotype is due to the intended knockdown or an interaction with an off @-@ target RNA can often be addressed by running another experiment to confirm that the observed morphant phenotype results from the knockdown of the expected target . This can be done by recapitulating the morphant phenotype with a second , non @-@ overlapping Morpholino targeting the same mRNA or by confirmation of the observed phenotypes by use of a mutant strain or dominant @-@ negative methods . As mentioned above , rescue of observed phenotypes by coinjecting a rescue mRNA is , when feasible , a reliable test of specificity of a Morpholino . 
