【摘要】 生物进化的主要趋势是由简单到复杂 ,由低级到高级。在整体进化的同时 ,生物界也广泛存在着局部的退化和简单化现象。为了研究生物的进化和退化并行、简单和复杂并存的现象 ,以及各种内、外部因素的影响 ,建立了一个考虑基因扩增/删除机制的进化模型 ,并对这个模型在各种影响因素下的进化过程进行了仿真研究。实验结果和理论分析表明 ,生物进化过程中的复杂化倾向主要是为了适应复杂多变的外部环境 ,但复杂的基因组或结构功能往往需要比较大的生存和繁殖成本 ,这又限制了复杂化的无限发展。当外部环境变化比较频繁 ,幅度比较大 ,而繁殖成本不高时 ,进化倾向于复杂化 ;当繁殖成本过高时 ,复杂化倾向被限制 ;而当外部环境变化很缓慢或基本稳定时 ,退化和简单化则成为主要趋势。更多还原

【Abstract】 One of the main trends of evolution is the development from simplicity to complexity, from lower organism to higher organism. At the same time, certain local degradation and simplification is also broadly existing. In this paper, a simulated evolutionary model that contains gene amplification and deletion was proposed and the evolutionary process of genomic complexity was simulated. The evolution of higher complex structure, the co-existence of varied order of complexity, and the influence of various factors on the evolution of complexity are discussed based on simulation results and theoretical analysis. It is shown that complexity is mainly caused by the adaptation to various complicated environments. Nevertheless, complex genome or structure and function require higher survival and replication cost, which limits the complication to develop infinitely. When the environment changes frequently and drastically, and the cost is not too high, then evolution is apt to produce complexity. When the cost is too high, the trends of complication is always limited. While the environment is relatively stable, degradation and simplification become the main trend.更多还原