Analyses of multiple whole-genome sequences from the same species have revealed that differences in gene content can be substantial, particularly in prokaryotes. Such variation has led to the recognition of pangenomes, the complete set of genes present in a species – consisting of core genes, present in all individuals, and accessory genes whose presence is variable. Questions now arise about how pangenomes originate and evolve. We describe how gene content variation can arise as a result of the combination of several processes, including random drift, selection, gain/loss balance, and the influence of ecological and epistatic interactions. We believe that identifying the contributions of these processes to pangenomes will need novel theoretical approaches and empirical data.

对同一物种的多个全基因组序列的分析表明，基因含量的差异可能很大，尤其是在原核生物中。这种变异导致了对泛基因组的识别，泛基因组是一个物种中存在的完整基因组——由存在于所有个体中的核心基因和存在可变的辅助基因组成。现在出现了关于泛基因组如何起源和进化的问题。我们描述了基因内容变异是如何由于几个过程的结合而产生的，包括随机漂移、选择、增益/损失平衡以及生态和上位相互作用的影响。我们认为，确定这些过程对泛基因组的贡献需要新的理论方法和经验数据。