Conclusion
This study demonstrates that feralisation is at least partly repeatable at the genetic and phenotypic level in chickens, and involves significant enrichment of shared sweeps between independently feral populations. These sweeps also show little overlap to those produced by recent improvement/ domestication in modern domestic birds, with a single exception that shows how artificially-selected genome regions can either retain signals of selection, or be continuously selected, during the recolonization of wild habitats. As mentioned earlier, it is important to note that most known improvement selective sweeps may not be representative of the earliest domestication-related genes (i.e. those polymorphisms/ mutations selected during the initial domestication process), as pointed out by Flink et al (2014). Unfortunately, unless (or until) all domestication genes are known, we cannot fully exclude the possibility of their involvement in feralisation. Nonetheless, our collective findings suggest that further studies of feralisation genomics will continue to produce novel and complex discoveries. For example, the two populations we compared herein exhibit both parallels and differences in their recent evolutionary trajectories, and have recruited haplotypes to high frequency that stem from both domesticated and wild sources. This complexity is perhaps unsurprising, given that feral populations consist of novel and uniquely human-impacted organisms, and that these organisms exhibit, to remarkable and often vexing degrees, a capacity to thrive in an increasingly human impacted world.