Institute of Evolutionary Biology and Environmental Studies, University of Zurich, CH-8057 Zurich, Switzerland; The Swiss Institute of Bioinformatics, CH-1015 Lausanne, Switzerland; Centre for Genomic Regulation (CRG), C/Dr. Aiguader 88, 08003 Barcelona, Spain.
Evolution. 2014 Jun;68(6):1775-91. doi: 10.1111/evo.12373. Epub 2014 Mar 20.
Gene duplication is important in evolution, because it provides new raw material for evolutionary adaptations. Several existing hypotheses about the causes of duplicate retention and diversification differ in their emphasis on gene dosage, subfunctionalization, and neofunctionalization. Little experimental data exist on the relative importance of gene expression changes and changes in coding regions for the evolution of duplicate genes. Furthermore, we do not know how strongly the environment could affect this importance. To address these questions, we performed evolution experiments with the TEM-1 beta lactamase gene in Escherichia coli to study the initial stages of duplicate gene evolution in the laboratory. We mimicked tandem duplication by inserting two copies of the TEM-1 gene on the same plasmid. We then subjected these copies to repeated cycles of mutagenesis and selection in various environments that contained antibiotics in different combinations and concentrations. Our experiments showed that gene dosage is the most important factor in the initial stages of duplicate gene evolution, and overshadows the importance of point mutations in the coding region.
基因复制在进化中很重要，因为它为进化适应提供了新的原始材料。关于保留和多样化的原因，有几个现有的假说，它们在强调基因剂量、亚功能化和新功能化方面存在差异。关于复制基因进化中基因表达变化和编码区变化的相对重要性，实验数据很少。此外，我们不知道环境对这种重要性的影响有多大。为了解决这些问题，我们在大肠杆菌中用 TEM-1 内酰胺酶基因进行了进化实验，以研究实验室中复制基因进化的初始阶段。我们通过在同一个质粒上插入两个 TEM-1 基因的副本来模拟串联复制。然后，我们在含有不同组合和浓度抗生素的各种环境中对这些副本进行了多次诱变和选择循环。我们的实验表明，在复制基因进化的初始阶段，基因剂量是最重要的因素，超过了编码区点突变的重要性。
