CircularResearchers at the University of Warwick have found another round of “conserved” non coding sequences, this time in the four plant species: the papaya, poplar, Arabidopsis and grape. And if the these similar DNA sequences are found in such disparate species, then the sequences must have been present in a very distant, and much simpler, common ancestor. The problem is these CNS’s are apparently rather clever. Not only do they appear to be regulating gene expression by influencing transcription factor binding, but many of the genes regulated by these sequences are themselves transcription factors. As one researcher explains:
So it’s the transcription factors that are regulating other transcription factors—which forms this idea of there being a core common network that is shared across different plant species.
So a long time ago random mutations just happened to construct a “core common network” where promoter regions controlled how transcription factors, also designed by random mutations, would regulate the expression of genes, which again were constructed by random mutations, of other transcription factors. And this “network” would then turn out to be a crucial component in all kinds of plants yet to be designed by evolution and its random mutations. It all makes perfect evolutionary sense.