Phytoene desaturase (lycopene-forming) Phytoene desaturase (lycopene-forming) Phytoene desaturase (lycopene-forming) (CrtI, "four-step phytoene desaturase") (, "15-cis-phytoene:acceptor oxidoreductase (lycopene-forming)") are enzymes found in archaea, bacteria and fungi that are involved in carotenoid biosynthesis. They catalyze the conversion of colorless 15-"cis"-phytoene into a bright red lycopene in a biochemical pathway called the poly-trans pathway. The same process in plants and cyanobacteria utilizes four separate enzymes in a poly-cis pathway. Bacterial phytoene desaturases were shown to require FAD as a cofactor for their function. During the chemical reaction in total four additional double bonds are introduced into phytoene: In 2000 it was discovered that the gene insertion
Cockatiel colour genetics Leading to ADMpied cockatiels being notoriously difficult to sex visually but being excellent examples for studies in genetic traits. However, in monomorphic species (i.e. conures, lovebirds, macaws, rosellas, etc.) the anti-di-morphic feature cannot be expressed while piedness still is. Therefore, Pied specimens of these species are called either Recessive Pied and/or Harlequin in budgerigar. Cinnamon and pearl mutations are sex-linked recessive. In Cinnamons, the eumelanin pigment are partially oxidized. Eumelanin granules are stopped at the brown stage of their development to end up in their natural black colour state. The pearl cockatiels' gene does not have any visual effect on