Oxala García-Rodríguez

Phylogeographic studies have been conducted on many different mammal species in order to track their recent demographic histories. The climatic fluctuations associated with the Last Glacial Maximum (LGM) appear to have had a profound influence on the geographic patterning of genetic diversity in mammals. However, most phylogenetic studies have focused on single species. Few have used a holistic approach covering multiple taxa to explore common patterns. Here, we conducted meta-analyses of mitochondrial DNA control region sequences, identifying haplotype diversity and private allelic richness patterns in a geographic context. Four general patterns emerged among European mammals: an east–west decline in variation, a Western-Central belt of the highest diversity, southern richness, and homogeneity with no geographic pattern. These patterns likely reflect the refugial origins of modern populations. The east–west variation decline suggests species with eastern LGM refugia; the Western-Central belt of the highest diversity may harbor taxa with cryptic northern refugia, while southern richness may correspond to traditional southern refugia. Species with homogeneity and no geographic pattern may have been panmictic without a specific refugium or may reflect the occurrence of both southern and cryptic northern refugia. Surprisingly, the “no pattern” phenomenon is seldom discussed and may frequently have been discounted. Our study emphasizes the importance of considering multiple taxa, providing valuable insights into the responses of European mammals to past climatic changes.

Background: The earliest records in Britain for the western European house mouse (Mus musculus domesticus) date from the Late Bronze Age. The arrival of this commensal species in Britain is thought to be related to human transport and trade with continental Europe. In order to study this arrival, we collected a total of 16 ancient mouse mandibulae from four early British archaeological sites, ranging from the Late Bronze Age to the Roman period. Results: From these, we obtained ancient mitochondrial DNA (mtDNA) house mouse sequences from eight house mice from two of the sites dating from the Late Bronze to Middle Iron Age. We also obtained five ancient mtDNA wood mouse (Apodemus spp.) sequences from all four sites. The ancient house mouse sequences found in this study were from haplogroups E (N = 6) and D (N = 2). Modern British house mouse mtDNA sequences are primarily characterised by haplogroups E and F and, much less commonly, haplogroup D. Conclusions: The presence of haplogroups D and E in our samples and the dating of the archaeological sites provide evidence of an early house mouse colonisation that may relate to Late Bronze Age/Iron Age trade and/or human expansion. Our results confirm the hypothesis, based on zooarchaeological evidence and modern mtDNA predictions, that house mice, with haplogroups D and E, were established in Britain by the Iron Age and, in the case of haplogroup E, possibly as early as the Late Bronze Age.

The earliest records in Britain for the western house mouse ( Mus musculus domesticus ) date from the Late Bronze Age. As a commensal species, the arrival to Britain is suggested to be related with human transport and trade. In order to study the arrival of the species in Britain, we collected a total of 16 ancient mouse mandibulae from some of the rare early sites with the species in the four British archaeological sites, ranging from the Late Bronze Age to the Roman period. From these, we obtained the first ancient mitochondrial DNA (mtDNA) house mouse sequences from the British Isles, including eight house mice from three different archaeological sites ranging from the Late Bronze Age to the Middle Iron Age. We also obtained five ancient mtDNA wood mouse ( Apodemus spp.) sequences from across all four sites. Modern British house mouse mtDNAs are primarily characterised by haplogroups E, F and, much less commonly, haplogroup D. The presence of haplogroups D and E in our samples provides evidence of an early house mouse colonisation that may be related with Late Bronze Age/Iron Age trade and/or expansions of humans. Our results confirm the hypothesis, based on zooarchaeological evidence and modern mtDNA predictions, that house mice with haplogroups D and E were established in Britain by the Iron Age and, in the case of haplogroup E, possibly even by the Late Bronze Age.

The Eurasian red squirrel ( Sciurus vulgaris ) is an emblematic species for conservation, and its decline in the British Isles exemplifies the impact that alien introductions can have on native ecosystems. Indeed, red squirrels in this region have declined dramatically over the last 60 years due to the spread of squirrelpox virus following the introduction of the gray squirrel ( Sciurus carolinensis ). Currently, red squirrel populations in Britain are fragmented and need to be closely monitored in order to assess their viability and the effectiveness of conservation efforts. The situation is even more dramatic in the South of England, where S. vulgaris survives only on islands (Brownsea Island, Furzey Island, and the Isle of Wight). Using the D‐loop, we investigated the genetic diversity and putative ancestry of the squirrels from Southern England and compared them to a European dataset composed of 1,016 samples from 54 populations. We found that our three populations were more closely related to other squirrels from the British Isles than squirrels from Europe, showed low genetic diversity, and also harbored several private haplotypes. Our study demonstrates how genetically unique the Southern English populations are in comparison with squirrels from the continental European range. We report the presence of four private haplotypes, suggesting that these populations may potentially harbor distinct genetic lineages. Our results emphasize the importance of preserving these isolated red squirrel populations for the conservation of the species.

Aim: In this study, we conduct a quantitative meta‐analysis to investigate broad patterns of genetic variation throughout large geographical regions in order to elucidate concordant geographical patterns across species and identify common historical processes to better inform the “cryptic refugia” versus the traditional “southern refugia” hypothesis debate.Location: Europe.Time period: Late Pleistocene to present day.Major taxa studied: Small mammals (Rodentia, Eulipotyphla).Methods: A meta‐analysis was performed on large‐scale patterns of genetic diversity for 19 species from 59 papers. For each species, haplotype and nucleotide diversity were calculated using the mitochondrial D‐loop and compared to the species’ range.Results: No consistent patterns were observed between mitochondrial DNA (mtDNA) diversity indices (nucleotide and haplotype diversity) and any of the indicators of distribution examined [latitude and longitude (max, min, centre, range)]. The patterns of genetic diversity observed in all the 19 species studied appear to be species‐specific.Main conclusions: In contrast to the traditional southern refugial hypotheses, we found no evidence for a consistent south–north post‐glacial expansion. Instead individual species appear to respond to climate oscillations in niche‐specific ways. This individual nature of each species’ phylogeographical history indicates a complex web of post‐glacial recolonization dynamics across Europe.

Aim: The distribution of the western house mouse (Mus musculus domesticus) around the world has been strongly influenced by the movement of humans. The close association between the house mouse and human phylogeography has been primarily studied in the peripheral distribution of the species. Here, we inferred the complex colonization history of Cyprus, situated close to the centre of the house mouse distribution and one of the first European islands to be colonized by the species. We investigated the resulting complexity of house mouse population genetics as well as considering the value of the house mouse as a bioproxy for studying modern human movement.Location: The study was carried out on Cyprus.Methods: The analysis was performed using 221 new mitochondrial D‐loop sequences and assessed the fine‐scale population genetic structure using 18 autosomal microsatellite loci from 191 modern house mice specimens.Results: We found a high genetic variability in the island that is illustrated by the presence of individuals from 9 of the 11 previously identified house mouse haplogroups for the D‐loop, reflecting the hub‐like nature of the island to mice. Two main waves of mouse introductions were tentatively identified based on coalescent and mismatch analysis. The first is apparently related to the Bronze Age expansion and the second one to more recent human movements. Cyprus represents an island with high complexity due to different introductions related to human transport and activity.Main conclusions: The dispersal of mice along with humans has left a complex footprint on the island with two main waves of introductions suggested. The phylogeography of the house mouse on Cyprus is in concordance with the complex human colonization history of the island and validates the use of the house mouse as a proxy to study human migration.