"The Simplicity of Metazoan Cell Lineages"
Developmental programs are thought to be both highly complex and highly modular, but there are no generally accepted ways of quantifying either of these properties. Here we introduce a measure of cell lineage complexity: the length of its shortest description. We then use this measure to estimate the complexity and degree of modularity of the embryonic lineages of four metazoan species from two different phyla. We find that these cell lineages are significantly simpler and more modular than expected by chance. Furthermore, evolutionary simulations suggest that the complexity of the embryonic lineages surveyed is near that of the simplest lineages evolvable assuming strong developmental constraints on the spatial positions of cells. We propose that selection for decreased complexity plays a major role in molding metazoan cell lineages.