Embryo Networks as Generative Divergent Integration

As the developmental phenotype grows and organizes, constituent cells engage in complex sets of interactions on their way to fully organized tissues. Networks can be extracted from the developmental phenotype based on the spatial proximity of cells, hypothetical signaling relationships, and physical connections. The generative nature of embryonic development (e.g. cell division and differentiation) results in networks that increasingly overlap but also diverge as developmental time elapses. This complexity emerges as a consequence of both functional differentiation and multiple scales of self-organization, from gene expression networks to anatomical networks. For newly dividing and differentiating cells in the embryo, network representations must incorporate new nodes and edges unique to the underlying generative process. In this submission, we will discuss integration of embryo networks and connectomes in development. These cellular-level networks provide us with networks of diverging and ultimately composite biological functions over time. While these networks describe and analyze a continuous structure, they also describe two dynamic processes: networks that grow and change shape over time, and network modules that exhibit divergent function over time. The two processes can be interpreted both in terms of attachment processes for newly-born (changes in structure) and newly-differentiated cells (changes in function). This model system might lead to new, biologically-specific principles for complex networks, particularly those that describe the paradox of divergent growth and connectivity processes under active functional integration.