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
Budgerigar colour genetics Budgerigar colour genetics The science of budgerigar colour genetics deals with the heredity of mutations which cause colour variation in the feathers of the species known scientifically as "Melopsittacus undulatus". Birds of this species are commonly known by the terms 'budgerigar', or informally just 'budgie'. The wildtype (natural-coloured or wild occurring) budgerigar's colour is called Lightgreen. The feathers of most parrot species, including budgerigars, contain both a black type of "melanin" named "eumelanin" along with a basic yellow pigment named psittacofulvin (psittacin for short). Some other parrot species produces a third pigment named advanced-psittacin which enables colour & tones ranging