Our rbcL data indicate that all three diverged at a very early stage in angiosperm evolution and probably represent three loosely related lines of evolution. The data also show that the Polygonales and Plumbaginales are not related to the Dilleniidae as suggested in another classification. Also, within the Caryophyllales, the families Carophyllaceae and Molluginaceae produce anthocyanin pigments while the majority of the other families in the order produce the unusual nitrogenous betalain pigments. This approach is now being applied to similar problems in the catkin-bearing taxa of the witchhazel subclass, the Hamamelidae. The Genetics of Pigment Inheritance Another project in progress studies the inheritance of flower pigments in the morning glory, Ipomoea purpurea Roth.
Most genetic studies depend on visual documentation of phenotypes.
However, the inheritance of various types of flavonoids, such as anthocyanins involves many intermediate flavonoid steps. Chromatographic analysis has been combined with data from genetic crosses to easily and rapidly indicate where genetic blocks have occurred in the flavonoid pathway. Such analyses, show tissue-specific mutations. This is significant in analyzing mobile genetic elements called transposable elements, which can change the phenotype of a flower depending on whether they are present or not. These classica chromatographic analyses can easily document at what point in the pathway these transposons exert their influence.