We have discussed in our lecture several instances
where a pattern of hox gene expression (i.e. a hox code) has been
used to confer identity on different regions of a structure or
tissue. For example, somites, neural crest, the splanchnic mesoderm
surrounding the digestive tube, the position of the limb fields,
and the different limb regions (to name just a few) are all
patterned by a hox code. These are all very different tissues. I
know what hox genes encode transcription factors. How is it
possible that the same set of transcription factors can specify the
identities of so many different structures/tissues