A regulatory gene, An2, controls structural genes within the flavonoid biosynthetic pathway. The inheritance of An2 expression in crosses between P. axillaris (an2) and P. exserta (An2+) was studied. Floral pigmentation was quantitatively inherited and involved the expression of a single regulatory gene (An2) and three structural genes (Hf1, An6 and Fl). White flowers were produced in an2- genotypes; while pigmented flowers were produced in An2+ genotypes. The intensity of pigmentation was determined by the interaction of An2 with An6, Hf1 and Fl, as well as substrate competition between the An6 and Fl encoded enzymes.
If the inline PDF is not rendering correctly, you can download the PDF file here.