Artificial Cells that Reproduce Using Spatially Distributed Asynchronous Parallel Processes

Replication time is among the most important components of a bacterial cell's reproductive fitness. Paradoxically, larger cells replicate in less time than smaller cells despite the fact that assembling a larger cell requires collecting and combining increased quantities of raw materials. This feat is accomplished through the prodigious use of parallel processing, chiefly the translation of mRNA into protein by tens of thousands of ribosomes acting in parallel. The massive over-expression of ribosomes permits protein synthesis, the limiting step in replication, to occur at a rate and scale that would be otherwise impossible. In computer science, spatial parallelism is the distribution of work across the nodes of a distributed-memory multicomputer system. Despite the fact that a non-negligible fraction of artificial life research is grounded in spatially parallel substrates, there have been no examples of artificial organisms that exploit spatial parallelism to replicate in less time than smaller organisms. This paper describes artificial cells defined in a combinator-based artificial chemistry that replicate in less time than smaller cells. This is achieved by employing extra copies of programs implementing the limiting steps in the process used by the cells to synthesize their component parts.