Transition Studies in Flowering Plants: Real-time Evolution   

by Rolf Baumberger

Molecular genetics 1

 Molecular genetic aspects 2

Three TFs involved in the MBW complex that regulates the anthocyanin pathway. 

The up-regulated MBW-complex triggers the enzymes along the anthocyanin pathway what results in red petal tissue. Interestingly short non-coding sequences may be involved in the up-regulating process. Thus TATA, GATGAT, of different lengths are included in the coding but more often in the non-coding sequences of the  TFs. It suggests that a transposon-like or CRISPR-like mechanism is involved. This way, the "yellow" flower can shift step by step from yellow, intermediary to the red stage, and partially back again.

Our current Hypothesis reads as follows:  

Pushmi-Pullyu Hypothesis 

The control genes of a Diplacus plant are modularly organized. Therefore, the question arises whether this form of organization must be reinvented each time during speciation, or whether it is not more resource-saving to adapt the control of the gene cascade in order to change evolutionarily. 

Therefore, we postulate the following:
A master regulator, "Pushmi-Pullyu," recruits the activity of corresponding RNA polymerases via the dynamic altering of the *TATA-motif lengths and thus also the newly built transcription factors, which are control variables for floral size and flower color.
Pushmi-Pullyu has a threshold value. It reacts mainly to environmental requirements. The system goes through learning process cycles, which has an optimizing effect. The new form is then changed on an individual basis in morphotype and genotype compared to the abandoned state.

see literature: 1; 2 chptr8; 3; 4; 5

*Also, TAATAT, TCTC, GAATGA, and similar repeats within coding regions or more frequently in flanking "non-coding" regions are being observed. Introns may, therefore, contain the instructions in TATA-Code for the proper function of the synthesis apparatus. These regions are prone to vary also in an epigenetic way.

Molecular Genetics 2