The gene regulatory apparatus that directs development is
encoded in the DNA, in the form of organized arrays of
transcription factor target sites. Genes are regulated by
interactions with multiple transcription factors and the
target sites for the transcription factors required for the
control of each gene constitute its cis-regulatory system.
These systems are remarkably complex. Their hardwired
internal organization enables them to behave as genomic
information processing systems. Developmental gene regulatory
networks consist of the cis-regulatory systems of all
the relevant genes and the regulatory linkages amongst
them. Though there is yet little explicit information, some
general properties of genomic regulatory networks have
become apparent. The key to understanding how genomic
regulatory networks are organized, and how they work, lies
in experimental analysis of cis-regulatory systems at all
levels of the regulatory network
