Article

Sexual reproduction reshapes the genetic architecture of digital organisms

Ecology, Evolutionary Biology and Behavior Program, Michigan State University, East Lansing, MI 48824, USA.
Proceedings of the Royal Society B: Biological Sciences (Impact Factor: 5.05). 03/2006; 273(1585):457-64. DOI: 10.1098/rspb.2005.3338
Source: PubMed

ABSTRACT

Modularity and epistasis, as well as other aspects of genetic architecture, have emerged as central themes in evolutionary biology. Theory suggests that modularity promotes evolvability, and that aggravating (synergistic) epistasis among deleterious mutations facilitates the evolution of sex. Here, by contrast, we investigate the evolution of different genetic architectures using digital organisms, which are computer programs that self-replicate, mutate, compete and evolve. Specifically, we investigate how genetic architecture is shaped by reproductive mode. We allowed 200 populations of digital organisms to evolve for over 10 000 generations while reproducing either asexually or sexually. For 10 randomly chosen organisms from each population, we constructed and analysed all possible single mutants as well as one million mutants at each mutational distance from 2 to 10. The genomes of sexual organisms were more modular than asexual ones; sites encoding different functional traits had less overlap and sites encoding a particular trait were more tightly clustered. Net directional epistasis was alleviating (antagonistic) in both groups, although the overall strength of this epistasis was weaker in sexual than in asexual organisms. Our results show that sexual reproduction profoundly influences the evolution of the genetic architecture.

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Available from: Charles Ofria, Jan 07, 2014
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    • "As Dennett (2002, p. E83) has emphasized, " evolution will occur whenever and wherever three conditions are met: replication, variation (mutation), and differential fitness (competition). " The Avida system fulfills all of these conditions, and it is thus a tractable model for investigating the general properties of evolving systems (Lenski et al. 1999, 2003; Adami et al. 2000; Wilke et al. 2001; Chow et al. 2004; Goings et al. 2004; Misevic et al. 2006; Pennock 2007; Clune et al. 2008, 2010). "
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    • "I conducted my experiments using Avida (Ofria and Wilke, 2004), an artificial life program designed to study questions in evolution, e.g., the complexity of epistasis (Lenski et al., 1999), the effect of mutational robustness on evolvability (Elena and Sanjuán, 2008), and the genetic architecture of sexual organisms (Misevic et al., 2006). Digital organisms in Avida consist of a sequence of computer instructions that encodes their ability to replicate and perform Boolean logic operations (or 'tasks'). "
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