Frank S A
Department of Ecology and Evolutionary Biology, University of California, Irvine 92717, USA.
J Theor Biol. 1995 Oct 7;176(3):403-10. doi: 10.1006/jtbi.1995.0208.
A dominant theme in the history of life has been the evolutionary innovations of cooperative symbioses: the first genomes near the origin of life, integrated prokaryotic cells, the complex symbiotic communities that evolved into modern eukaryotic cells, lichens, mycorrhizae, and so on. In this paper, a model of cooperative symbiosis that shows a threshold condition for the evolution of cooperation is analyzed. The threshold is not easily passed, but cooperative evolution proceeds rapidly once a symbiosis overcomes the threshold. In the model presented here, each species has genetic variability for a symbiotic trait. The trait imposes a reproductive cost on its bearer but enhances the reproduction of its partner species. For example, in the origin of genetic systems, the trait may cause biochemical synergism for the rate of replication of primitive RNA strands as in Eigen and Schuster's hypercycle model. Models of growth are contrasted with synergism, which are most appropriate for the evolution of genetic systems and for mutualisms such as lichens, with the strategic and psychological applications of the Prisoner's Dilemma model.
生命起源附近的第一批基因组、整合的原核细胞、进化为现代真核细胞的复杂共生群落、地衣、菌根等等。在本文中，分析了一个合作共生模型，该模型展示了合作进化的一个阈值条件。这个阈值不容易跨越，但一旦共生关系跨越了这个阈值，合作进化就会迅速进行。在这里提出的模型中，每个物种对于一个共生性状都有遗传变异性。该性状会给其携带者带来繁殖成本，但会提高其伙伴物种的繁殖率。例如，在遗传系统的起源中，该性状可能会像艾根和舒斯特的超循环模型那样，对原始RNA链的复制速率产生生化协同作用。生长模型与协同作用形成对比，协同作用最适用于遗传系统的进化以及诸如地衣之类的互利共生关系，同时也与囚徒困境模型的策略和心理应用形成对比。
