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The Rufous-backed Robin (Turdus rufopalliatus) is endemic to deciduous and semideciduous tropical forests of western Mexico. Of the currently recognized subspecies, T. r. graysoni, from the Tres Marías Islands and nearby coastal Nayarit, has been considered a separate species; however, this treatment has been challenged due to an apparent contact zone on the mainland, although no hybrids have ever been recorded. Here, we use mitochondrial DNA sequences from individuals sampled across the species' range to assess their phylogeographic relationships. We found reciprocal monophyly between Tres Marías Islands and mainland populations, which share no haplotypes between them. Evolutionary divergence detected within T. rufopalliatus suggests that mainland and island populations have been isolated from each other, and divergence decreases if insular populations are excluded. Demographic parameters suggest that populations are in the process of a rapid expansion from ancestral populations with a lower population size. These results are consistent with morphometric and plumage differences that have been used to recognize the Tres Marías Islands populations from the mainland ones, thus suggesting species status of the island form.

The Sicilian wolf represented the only population of wolves living on a Mediterranean island until the first half of the twentieth century (1930s-1960s). Previous studies hypothesised that they remained isolated from mainland wolves from the end of the Last Glacial Maximum (LGM), until human persecutions led them to extinction. There are only seven known Sicilian wolf specimens from the 19th and 20th century preserved in museums in Italy and recent morphometric analyses assigned them to the new subspecies Canis lupus cristaldii 10. To better understand the origins of the Sicilian wolf, and its relationship to other wolf populations, we sequenced four whole genomes (3.8x-11.6x) and five mitogenomes. We investigated the relationship between Sicilian wolves and other modern breeds to identify potential admixture. Furthermore, considering that the last land-bridge between Sicily and Italy disappeared after the LGM, around 17 kya, we explored the possibility that the Sicilian wolf retained ancestry from ancient wolf and dog lineages. Additionally, we explored whether the long-term isolation might have affected the genomic diversity, inbreeding levels and genetic load of the Sicilian wolf. Our findings show that the Sicilian wolves shared most ancestry with the modern Italian wolf population but are better modelled as admixed with European dog breeds, and shared traces of Eneolithic and Bronze age European dogs. We also find signatures of severe inbreeding and low genomic diversity at population and individual levels due to long-term isolation and drift, suggesting also low effective population size.

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SummaryThe domestic pigeon’s exceptional phenotypic diversity was key in developing Darwin’s Theory of Evolution and establishing the concept of artificial selection in domestic species. However, unlike its domestic counterpart, its wild progenitor, the rock doveColumba livia, has received considerably less attention. Therefore, questions regarding their domestication, evolution, taxonomy, and conservation status remain unresolved. We generated whole-genome sequencing data from 65 historical rock dove samples representing all currently recognised subspecies and spanning the species’ original geographic distribution. Our dataset includes three specimens from Darwin’s collection and the type specimens of five different taxa. We characterised rock doves’ population structure, genomic diversity and gene-flow patterns. We show the West African subspeciesC. l. gymnocyclusis basal to rock doves and domestic pigeons. Our results show gene-flow signals between the rock dove’s sister speciesC. rupestrisand all rock doves except the West African populations. Our results led us to propose an evolutionary model for the rock dove considering the Pleistocene refugia theory. We propose that today’s rock dove genetic diversity and introgression patterns derive from a history of allopatric cycles and dispersion waves during the Quaternary glacial and interglacial periods. To explore the rock dove domestication history, we combined our new dataset with available genomes from domestic pigeons. Our results point to at least one domestication event in the Levant region that gave rise to all domestic breeds analysed in this study. Finally, we propose a species-level taxonomic arrangement to reflect the evolutionary history of the West African rock dove populations.