back-mutation

https://doi.org/10.1351/goldbook.15494
Process that reverses the effect of a mutation which had inactivated a gene; thus, it restores the wild phenotype.
Source:
PAC, 2007, 79, 1153. (Glossary of terms used in toxicology, 2nd edition (IUPAC Recommendations 2007)) on page 1173 [Terms] [Paper]