 The first documented double-flowered mutant of "Arabidopsis", a model organism for plant development and genetics, was recorded in 1873.The mutated gene likely responsible for the phenotype, AGAMOUS, was cloned and characterized in 1990 in Elliot Meyerowitz's lab as part of his study of molecular mechanisms of pattern formation in flowers.Double-flower forms often arise when some or all of the stamens in a flower are replaced by petals.