Martin Reese, Tate Ann T
Department of Biological Sciences, Vanderbilt University, Nashville TN, 37235.
Evolutionary Studies Initiative, Vanderbilt University, Nashville, Tennessee, USA.
bioRxiv. 2023 Oct 10:2023.10.06.561276. doi: 10.1101/2023.10.06.561276.
Many genes and signaling pathways within plant and animal taxa drive the expression of multiple organismal traits. This form of genetic pleiotropy instigates trade-offs among life-history traits if a mutation in the pleiotropic gene improves the fitness contribution of one trait at the expense of another. Whether or not pleiotropy gives rise to conflict among traits, however, likely depends on the resource costs and timing of trait deployment during organismal development. To investigate factors that could influence the evolutionary maintenance of pleiotropy in gene networks, we developed an agent-based model of co-evolution between parasites and hosts. Hosts comprise signaling networks that must faithfully complete a developmental program while also defending against parasites, and trait signaling networks could be independent or share a pleiotropic component as they evolved to improve host fitness. We found that hosts with independent developmental and immune networks were significantly more fit than hosts with pleiotropic networks when traits were deployed asynchronously during development. When host genotypes directly competed against each other, however, pleiotropic hosts were victorious regardless of trait synchrony because the pleiotropic networks were more robust to parasite manipulation, potentially explaining the abundance of pleiotropy in immune systems despite its contribution to life history trade-offs.
植物和动物分类群中的许多基因和信号通路驱动多种生物体性状的表达。如果多效性基因中的突变以牺牲另一个性状为代价提高了一个性状的适合度贡献，这种形式的基因多效性会促使生活史性状之间产生权衡。然而，多效性是否会导致性状之间的冲突，可能取决于生物体发育过程中性状表现的资源成本和时间安排。为了研究可能影响基因网络中多效性进化维持的因素，我们开发了一个寄生虫与宿主共同进化的基于主体的模型。宿主由信号网络组成，这些网络必须忠实地完成一个发育程序，同时还要抵御寄生虫，并且性状信号网络在进化以提高宿主适合度时可能是独立的，或者共享一个多效性成分。我们发现，当性状在发育过程中异步表现时，具有独立发育和免疫网络的宿主比具有多效性网络的宿主更适合。然而，当宿主基因型直接相互竞争时，多效性宿主无论性状同步情况如何都会获胜，因为多效性网络对寄生虫操纵更具抗性，这可能解释了尽管多效性对生活史权衡有影响，但免疫系统中多效性却很丰富的现象。
