  A proof is presented that gene regulatory networks (GRNs) based solely on
transcription factors cannot control the development of complex multicellular
life. GRNs alone cannot explain the evolution of multicellular life in the
Cambrian Explosion. Networks are based on addressing systems which are used to
construct network links. The more complex the network the greater the number of
links and the larger the required address space. It has been assumed that
combinations of transcription factors generate a large enough address space to
form GRNs that are complex enough to control the development of complex
multicellular life. However, it is shown in this article that transcription
factors do not have sufficient combinatorial power to serve as the basis of an
addressing system for regulatory control of genomes in the development of
complex organisms. It is proven that given $n$ transcription factor genes in a
genome and address combinations of length $k$ then there are at most $n/k$
k-length transcription factor addresses in the address space. The complexity of
embryonic development requires a corresponding complexity of control
information in the cell and its genome. Therefore, a different addressing
system must exist to form the complex control networks required for complex
control systems. It is postulated that a new type of network evolved based on
an RNA-DNA addressing system that utilized and subsumed the extant GRNs. These
new developmental control networks are called CENES (for Control genes). The
evolution of these new higher networks would explain how the Cambrian Explosion
was possible. The architecture of these higher level networks may in fact be
universal (modulo syntax) in the genomes of all multicellular life.
