Now, in the evolutionary move from
unicellular to multicellular organisms, the protein expressions of genes became
“meaningful” to the genomes of other cells, that is: as signifying something
other than themselves, such that they became a currency of symbolic exchange
between cells — just as the behavioural expressions of ‘senser-sensing’ became
a currency of symbolic exchange between (the neurological systems of) social
species of animals.
Dawkins (2004: 345):
[I]t is the behaviour of cells that determines embryonic development. Cells attract, or repel, other cells. … They secrete chemicals which may diffuse outwards and influence other cells, even some distance away. … Like termites co-operating to build a mound, cells ‘know’ what to do by reference to the neighbouring cells with whom they find themselves in contact, and in response to chemicals in gradients of concentration.
We will hypothesise, on the model of
protolanguage proposed by Halliday, that intercellular semiosis also involves
the integration of two domains: in this case the inner world of the cell and
the outer world around it.