Eugene D'Aquili's work in Biogenetic Structuralism also referenced Chapple's work. Garstang was known for his vehement opposition to Ernst Haeckel's Biogenetic Law, now discredited. Paibok also has a set of additional powers thanks to biogenetic engineering by Skrull scientists. Biogenetic precursor of all indole alkaloids is the amino acid tryptophan. Prior to shooting Simmons, she searches South America for a biogenetic weapon for her boss. Since early in the twentieth century, Haeckel's "biogenetic law" has been refuted on many fronts.