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: Mothers against decapentaplegic homolog 1 Mothers against decapentaplegic homolog 2 Mothers against decapentaplegic homolog 3 Mothers against decapentaplegic homolog 4 Mothers against decapentaplegic homolog 5 Mothers against decapentaplegic homolog 6 Mothers against decapentaplegic homolog 7 Mothers against decapentaplegic homolog 9 References Proteins SMAD (protein)