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Project Progress

To address the Darwinian Transition question, we built a quasi-species model of interacting organisms that includes HGT. We ran the simulation in an environment which exhibited a “Mount Fuji” fitness landscale. We discovered that for early times, the system exhibited a progenote phase, with rampant HGT and no unique species. After some time, a transition occurred and HGT switched off, leading to tree-like vertical evolution. It is important to emphasize that the transition is spontaneous and occurs after the population of organisms have evolved their fitness. HGT is still operative, but the actual effect of it becomes minimal because the population has a whole is now near the fitness peak and the likelihood of an improved gene being transferred becomes correspondingly smaller. In other words, HGT drives itself into a regime where it is ineffective. The Darwinian Transition occurs without fine tuning or external factors being adjusted. This result contrasts with earlier theories for the Darwinian Transition which put in by hand the down-regulation of HGT as the organismal complexity increased. In summary, this calculation shows how the Darwinian Transition emerges naturally from HGT dynamics.