Data from: The evolutionary fate of heterogeneous gene duplications: a precarious overdominant equilibrium between environment, sublethality and complementation.

Gene duplications occur at a high rate. Although most appear detrimental, some homogeneous duplications (identical gene copies) can be selected for beneficial increase in produced proteins. Heterogeneous duplications, which combine divergent alleles of a single locus, are seldom studied due to the paucity of empirical data. We investigated their role in an ongoing adaptive process at the ace-1 locus in Culex pipiens mosquitoes. We assessed the worldwide diversity of the ace-1 alleles (single-copy, susceptible S and insecticide-resistant R, and duplicated D that pair one S and one R copy), analyzed their phylogeography, and measured their fitness to understand their early dynamics using population genetics models. It provides a coherent and comprehensive evolutionary scenario. We show that D alleles are present in most resistant populations, and display a higher diversity than R alleles (27 vs. 4). Most appear to result from independent unequal crossing-overs between local single-copy alleles, suggesting a recurrent process. Most duplicated alleles have a limited geographic distribution, probably resulting from their homozygous sublethality (HS phenotype). In addition, heterozygotes carrying different HS D alleles showed complementation, indicating different recessive lethal mutations. Due to mosaic insecticide control practices, balancing selection (overdominance) plays a key role in the early dynamics heterogeneous duplicated alleles; it also favors a high local polymorphism of HS D alleles in natural populations (overdominance reinforced by complementation). Overall our study shows that the evolutionary fate of heterogeneous duplications (and their long-term role) depends on finely balanced selective pressures due to the environment and to their genomic structure.

基因重复（gene duplications）的发生频率颇高。尽管多数基因重复会带来有害后果，但部分同源基因重复（homogeneous duplications，即完全一致的基因拷贝）可因编码蛋白质产量的有益提升而受到正向选择。而异源基因重复（heterogeneous duplications）则结合了单个基因座的不同等位基因，由于实证数据匮乏，这类重复的相关研究相对较少。
我们以淡色库蚊（Culex pipiens）的ace-1基因座（ace-1 locus）正在进行的适应性演化过程为研究对象，探究了异源基因重复在此过程中的作用。
我们对ace-1等位基因的全球多样性展开了评估：这些等位基因包括单拷贝的敏感型S、抗杀虫剂型R，以及同时包含一个S拷贝与一个R拷贝的重复型D；我们还分析了它们的系统地理学特征，并借助种群遗传学模型测算其适合度，以解析这类等位基因的早期动态变化。
本研究构建了一套连贯且全面的演化场景。研究结果显示，重复型D等位基因在绝大多数抗杀虫剂种群中均有分布，且其多样性高于R等位基因（分别为27种与4种）。多数D等位基因似乎源自本地单拷贝等位基因之间独立发生的不等交换（unequal crossing-overs），这表明该过程具有反复性。
多数重复型等位基因的地理分布范围较为有限，这一现象大概率与其纯合亚致死表型（HS phenotype）有关。此外，携带不同HS型D等位基因的杂合子表现出互补效应，提示存在多种不同的隐性致死突变。
鉴于镶嵌式杀虫剂防治策略的应用，平衡选择（balancing selection，超显性overdominance）在异源重复型等位基因的早期动态变化中发挥着关键作用；同时，该选择过程也推动了自然种群中HS型D等位基因的高水平局部多态性，互补效应进一步强化了超显性的作用。
总体而言，本研究表明，异源基因重复的演化命运（及其长期演化作用）取决于环境与基因组结构共同塑造的精细平衡的选择压力。