Epigenetic potential, defined as the capacity for epigenetically-mediated phenotypic plasticity, may play an important role during range expansions. During range expansions, populations may encounter relatively novel challenges while experiencing lower genetic diversity. Phenotypic plasticity via epigenetic potential might be selectively advantageous at the time of initial introduction or during spread into new areas, enabling introduced organisms to cope rapidly with novel challenges. Here, we asked whether one form of epigenetic potential (i.e. the abundance of CpG sites) in three microbial surveillance genes: Toll-like Receptors 1B (TLR1B), 2A (TLR2A), and 4 (TLR4) varied between native and introduced house sparrows (Passer domesticus). Using an opportunistic approach based on samples collected from sparrow populations around the world, we found that introduced birds had more CpG sites in TLR2A and TLR4, but not TLR1B, than native ones. Introduced birds also lost more CpG sites in TLR1B, gained more CpG sites in TLR2A, and lost fewer CpG sites in TLR4 compared to native birds. These results were not driven by differences in genetic diversity or population genetic structure, and many CpG sites fell within predicted transcription factor binding sites (TFBS), with losses and gains of CpG sites altering predicted TFBS. Although we lacked statistical power to conduct the most rigorous possible analyses, these results suggest that epigenetic potential may play a role in house sparrow range expansions, but additional work will be critical to elucidating how epigenetic potential affects gene expression and hence phenotypic plasticity at the individual, population, and species levels.

中文翻译：

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家麻雀（Passerdomesticus）本地和引进种群的表观遗传潜力

表观遗传潜力，定义为表观遗传介导的表型可塑性的能力，可能在范围扩展过程中发挥重要作用。在范围扩展期间，种群可能会遇到相对新颖的挑战，同时经历较低的遗传多样性。通过表观遗传潜力的表型可塑性可能在最初引入时或在传播到新区域的过程中具有选择性优势，使引入的生物能够快速应对新的挑战。在这里，我们询问了三种微生物监测基因中的一种表观遗传潜力（即 CpG 位点的丰度）：Toll 样受体 1B (TLR1B)、2A (TLR2A) 和 4 (TLR4) 在本地和引入麻雀之间是否存在差异（国内传球手）。使用基于从世界各地麻雀种群收集的样本的机会主义方法，我们发现引入的鸟类在 TLR2A 和 TLR4 中有更多的 CpG 位点，但在 TLR1B 中没有，比原生鸟类多。与本地鸟类相比，引入的鸟类在 TLR1B 中也失去了更多的 CpG 位点，在 TLR2A 中获得了更多的 CpG 位点，而在 TLR4 中丢失的 CpG 位点更少。这些结果不是由遗传多样性或种群遗传结构的差异驱动的，许多 CpG 位点落在预测的转录因子结合位点 (TFBS) 内，CpG 位点的丢失和增加会改变预测的 TFBS。虽然我们缺乏进行最严格的分析的统计能力，但这些结果表明表观遗传潜力可能在麻雀范围扩大中发挥作用，但额外的工作对于阐明表观遗传潜力如何影响基因表达以及个体表型可塑性至关重要、种群和物种水平。