Many interesting new questions are associated
with these observations. Is there any correlation
between the number of signalling genes and the
diversification of body plans? Does the number of
types of signalling pathway hamper morphological
evolution? Is the flexibility of signalling systems sufficient
to explain the novelties of body plans? How are
new components integrated into existing networks,
and how does this change the behaviour of a signalling
network? How do signalling systems really
evolve at the microevolutionary level, that is, what
type of mutations occur and how are such changes