Mothers against decapentaplegic

Mothers against decapentaplegic is a protein from the SMAD family that was discovered in Drosophila. During Drosophila research, it was found that a mutation in the gene in the mother repressed the gene decapentaplegic in the embryo. The phrase "Mothers against" was added as a humorous take-off on organizations opposing various issues e.g. Mothers Against Drunk Driving (MADD); and based on a tradition of such unusual naming within the gene research community.

Several human homologues are known:

...
Wikipedia