The Pleistocene was an epoch of extreme climatic and environmental changes. How individual species responded to the repeated cycles of warm and cold stages is a major topic of debate. For the European fauna and flora, an expansion-contraction model has been suggested, whereby temperate species were restricted to southern refugia during glacial times and expanded northwards during interglacials, including the present interglacial (Holocene). Here, we test this model on the red deer (Cervus elaphus) a large and highly mobile herbivore, using both modern and ancient mitochondrial DNA from the entire European range of the species over the last c. 40,000 years. Our results indicate that this species was sensitive to the effects of climate change. Prior to the Last Glacial Maximum (LGM) haplogroups restricted today to South-East Europe and Western Asia reached as far west as the UK. During the LGM, red deer was mainly restricted to southern refugia, in Iberia, the Balkans and possibly in Italy and South-Western Asia. At the end of the LGM, red deer expanded from the Iberian refugium, to Central and Northern Europe, including the UK, Belgium, Scandinavia, Germany, Poland and Belarus. Ancient DNA data cannot rule out refugial survival of red deer in North-West Europe through the LGM. Had such deer survived, though, they were replaced by deer migrating from Iberia at the end of the glacial. The Balkans served as a separate LGM refugium and were probably connected to Western Asia with genetic exchange between the two areas.

Human colonization of the New World is generally believed to have entailed migrations from Siberia across the Bering isthmus. However, the limited archaeological record of these migrations means that details of the timing, cause and rate remain cryptic. Here, we have used a combination of ancient DNA, 14C dating, hydrogen and oxygen isotopes, and collagen sequencing to explore the colonization history of one of the few other large mammals to have successfully migrated into the Americas at this time: the North American elk ( Cervus elaphus canadensis ), also known as wapiti. We identify a long-term occupation of northeast Siberia, far beyond the species’s current Old World distribution. Migration into North America occurred at the end of the last glaciation, while the northeast Siberian source population became extinct only within the last 500 years. This finding is congruent with a similar proposed delay in human colonization, inferred from modern human mitochondrial DNA, and suggestions that the Bering isthmus was not traversable during parts of the Late Pleistocene. Our data imply a fundamental constraint in crossing Beringia, placing limits on the age and mode of human settlement in the Americas, and further establish the utility of ancient DNA in palaeontological investigations of species histories.

Near Eastern wild boars possess a characteristic DNA signature. Unexpectedly, wild boars from Israel have the DNA sequences of European wild boars and domestic pigs. To understand how this anomaly evolved, we sequenced DNA from ancient and modern pigs from Israel. Pigs from Late Bronze Age (until ca. 1150 BCE) in Israel shared haplotypes of modern and ancient Near Eastern pigs. European haplotypes became dominant only during the Iron Age (ca. 900 BCE). This raises the possibility that European pigs were brought to the region by the Sea Peoples who migrated to the Levant at that time. Then, a complete genetic turnover took place, most likely because of repeated admixture between local and introduced European domestic pigs that went feral. Severe population bottlenecks likely accelerated this process. Introductions by humans have strongly affected the phylogeography of wild animals, and interpretations of phylogeography based on modern DNA alone should be taken with caution.

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Aim The status of geographical units within species and species complexes is debated for many taxa, with many molecular studies failing to detect phenotypically defined subspecies. The history and longevity of geographical patterns are also generally very poorly understood. We examine Holarctic red deer (Cervus elaphus and related forms), incorporating ancient DNA to ask whether the present phylogeography has persisted through climatic perturbations or is a relatively recent phenomenon. Location Holarctic (Europe, northern Asia and North America). Methods We obtained 21 modern and 30 Holocene and Late Pleistocene samples, which together with published data resulted in 180 individuals spanning 21 nominal extant and one extinct subspecies. Phylogenetic analyses were carried out on 748‐bp of mitochondrial DNA (cytochrome b and control region). Where possible, the morphology of DNA‐yielding ancient samples was examined to assess subspecies identity. Results Major clades within the red deer complex are upheld, but subspecies within them receive varying support. The ancient phylogeographical structure conforms in significant part to the modern situation, but some haplogroups no longer survive. Moreover, there have been substantial shifts in geographical ranges through time. Wapitoids spread as far west as Romania in the last glaciation, and elaphoids reached eastward to the Ural Mountains. A possible contact zone between the two lineages stretched from the Urals through the Crimea to Eastern Europe. Main conclusions Ancient DNA and morphology are strongly complementary in elucidating population history. Through the past 50 kyr, the major lineages of red deer, and some of the subspecies groups within them, have maintained their genetic and morphological integrity and their core geographical distributions, despite range expansions and contractions and likely contact between the haplogroups (with potential for hybridization).