Recent work indicates that feralisation is not a simple reversal of domestication, and therefore raises questions about the predictability of evolution across replicated feral populations. In the present study we compare genes and traits of two independently established feral populations of chickens (Gallus gallus) that inhabit archipelagos within the Pacific and Atlantic regions to test for evolutionary parallelism and/or divergence. We find that feral populations from each region are genetically closer to one another than other domestic breeds, despite their geographical isolation and divergent colonisation histories. Next, we used genome scans to identify genomic regions selected during feralisation (selective sweeps) in two independently feral populations from Bermuda and Hawaii. Three selective sweep regions (each identified by multiple detection methods) were shared between feral populations, and this overlap is inconsistent with a null model in which selection targets are randomly distributed throughout the genome. In the case of the Bermudian population, many of the genes present within the selective sweeps were either not annotated or of unknown function. Of the nine genes that were identifiable, five were related to behaviour, with the remaining genes involved in bone metabolism, eye development and the immune system. Our findings suggest that a subset of feralisation loci (i.e. genomic targets of recent selection in feral populations) are shared across independently established populations, raising the possibility that feralisation involves some degree of parallelism or convergence and the potential for a shared feralisation ‘syndrome’.

中文翻译：

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独立野生原鸡种群的选择和祖先信号

最近的研究表明，野化并不是驯化的简单逆转，因此引发了关于复制野化种群进化的可预测性的问题。在本研究中，我们比较了两个独立建立的野生鸡群的基因和性状（鸡内金）居住在太平洋和大西洋地区的群岛，以测试进化的平行性和/或分歧。我们发现，来自每个地区的野生种群在基因上比其他家养品种更接近，尽管它们地理上孤立且殖民历史不同。接下来，我们使用基因组扫描来识别来自百慕大和夏威夷的两个独立野生种群中野化（选择性扫描）过程中选择的基因组区域。野生种群之间共享三个选择性扫描区域（每个区域都通过多种检测方法识别），这种重叠与零模型不一致，在零模型中选择目标随机分布在整个基因组中。就百慕大人口而言，选择性扫描中存在的许多基因要么没有注释，要么功能未知。在可识别的九个基因中，五个与行为有关，其余基因与骨代谢、眼睛发育和免疫系统有关。我们的研究结果表明，野化位点的子集（即野化种群中最近选择的基因组目标）在独立建立的种群之间共享，这增加了野化涉及某种程度的并行性或收敛性的可能性，以及共享野化“综合症”的可能性。