Abstract Polyketide synthases (PKSs) are crucial multidomain enzymes in diverse natural product biosynthesis. Parrots use a type I PKS to produce a unique pigment called psittacofulvin in their feathers. In domesticated budgerigars and lovebirds. the same amino acid substitution (R644W) within malonyl/acetyltransferase (MAT) domain of this enzyme has been shown to cause the blue pheno... https://www.roneverhart.com/Gul-Rune/