Immunity genes are proposed to be informative about evolutionary processes acting upon introduced populations (e.g., showing signatures of selection). This is because immunity genes are expected to be under pathogen-mediated selection, and this type of selection can be more pronounced when individuals are exposed to new environmental conditions. Here we assessed innate immune genetic diversity, via Toll-like receptors (TLRs), to quantify genetic differentiation between a deliberately introduced population of dunnocks (Prunella modularis) in New Zealand and its source population in the United Kingdom. We also asked whether the introduced population shows signatures of intergenerational and current selection in TLR. We expect intergenerational and current selection patterns because New Zealand dunnocks have been exposed to new environmental conditions following their introduction around the late 1800s, which may have driven pathogen-mediated selection. Counter to our expectation, we found only weak and non-significant genetic differentiation between the introduced and source populations. Further, the levels of genetic differentiation (GST′) found in TLRs were similar to those found in microsatellites across the populations. Dunnocks, in general, have been under strong purifying selection over evolutionary time, but we found little evidence to support signatures of contemporary selection in TLR in the introduced population. Notably, however, we found a statistically significant heterozygosity advantage for males in TLR3, which lends support to possible current selection acting upon the introduced population. Overall, it appears that New Zealand dunnocks have retained a high proportion of the immunogenetic diversity of the source population, and that such diversity has probably been sufficient to defend against the potential pathogens found in New Zealand. Our results may explain—at least in part—why the introduction of dunnocks has been so successful; dunnocks have become one of the most common birds in New Zealand.

中文翻译：

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使用先天免疫基因多样性评估 dunnocks 引入新西兰

建议免疫基因提供有关作用于引入种群的进化过程的信息（例如，显示选择特征）。这是因为免疫基因预计会受到病原体介导的选择，而当个体暴露于新的环境条件时，这种类型的选择会更加明显。在这里，我们通过 Toll 样受体 (TLR) 评估了先天免疫遗传多样性，以量化新西兰故意引入的 dunnocks（夏枯草）种群与其在英国的源种群之间的遗传差异。我们还询问引入的种群是否显示出 TLR 中代际和当前选择的特征。我们预计会出现代际和当前的选择模式，因为新西兰 dunnocks 在 1800 年代后期引入后已经暴露于新的环境条件，这可能推动了病原体介导的选择。与我们的预期相反，我们发现引入种群和来源种群之间只有微弱且不显着的遗传差异。此外，在 TLR 中发现的遗传分化 (GST') 水平与在整个种群的微卫星中发现的相似。一般来说，Dunnocks 在进化过程中一直处于强烈的净化选择之下，但我们发现几乎没有证据支持引入种群中 TLR 中当代选择的特征。然而，值得注意的是，我们发现 TLR3 中男性的杂合性优势具有统计学意义，这有助于支持当前可能对引入的种群起作用的选择。总体而言，新西兰鸭子似乎保留了源种群免疫遗传多样性的很大一部分，这种多样性可能足以抵御在新西兰发现的潜在病原体。我们的结果可能至少部分解释了为什么引入 dunnocks 如此成功；dunnocks 已成为新西兰最常见的鸟类之一。我们的结果可能至少部分解释了为什么引入 dunnocks 如此成功；dunnocks 已成为新西兰最常见的鸟类之一。我们的结果可能至少部分解释了为什么引入 dunnocks 如此成功；dunnocks 已成为新西兰最常见的鸟类之一。