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中国科学院爱因斯坦讲席讲授报告会预告

2014-09-18 分享到:
  报告人:Prof. Paul Rainey
  报告时间地点:9月22日惠联楼四楼 大报告厅9:30
  报告题目及内容简介:
  The evolutionary transition from single cells to multicellularity
  Cooperation is central to the emergence of multicellular life, however the means by which the earliest collectives maintained integrity in the face of destructive cheating types is unclear.  One idea posits cheats as a primitive germ line in a life cycle that facilitates collective reproduction.  Here we describe an experiment in which simple cooperating lineages of bacteria were propagated under a selective regime that rewarded collective-level persistence.  Collectives reproduced via life cycles that either embraced, or purged, cheating types.  When embraced, the life cycle alternated between phenotypic states.  Selection fostered inception of a developmental switch that underpinned the emergence of collectives whose fitness, during the course of evolution, became decoupled from the fitness of constituent cells.  Such development and decoupling did not occur when groups reproduced via a cheat-purging regime.  These findings capture key events in the evolution of Darwinian individuality during the transition from single cells to multicellularity.
  单细胞生物到多细胞生物的演化变迁
  合作是解释多细胞生物起源的核心, 但是合作者面临着欺诈者的破坏性挑战。当前一个重大的悬而未决的问题是, 在最初的多细胞生命形式中,细胞个体之间的合作是通过何种方式来维系的。最新的一个假说认为,欺诈者具有生命周期中原始胚系细胞的功能,从而促进多细胞体系的整体繁殖。为了实验证明这一假说,我们建立了一个简单的细菌合作模型,可以通过改变自然选择的条件来奖赏群体水平中的合作行为。 生命周期的整体繁衍既可以在接纳欺诈者,也可以在清除欺诈者的前提下实现。在接纳欺诈者的时候,生命周期中就会涉及到不同表现型(发育形式)的转换。自然选择的结果导致群体的整体适应性与个体组成细胞的个体适应性的分离。而这种发育方式的转换和适应性的分离在排除了欺诈者的情况下是不可能实现的。本项研究通过实验演示了达尔文个体进化过程中涉及单细胞生物向多细胞生物转换的几个关键步骤。