Dogs were present in the Americas before the arrival of European colonists, but the origin and fate of these precontact dogs are largely unknown. We sequenced 71 mitochondrial and 7 nuclear genomes from ancient North American and Siberian dogs from time frames spanning ~9000 years. Our analysis indicates that American dogs were not derived from North American wolves. Instead, American dogs form a monophyletic lineage that likely originated in Siberia and dispersed into the Americas alongside people. After the arrival of Europeans, native American dogs almost completely disappeared, leaving a minimal genetic legacy in modern dog populations. The closest detectable extant lineage to precontact American dogs is the canine transmissible venereal tumor, a contagious cancer clone derived from an individual dog that lived up to 8000 years ago.

No abstract

Near the end of the Pleistocene epoch, populations of the woolly mammoth (Mammuthus primigenius) were distributed across parts of three continents, from western Europe and northern Asia through Beringia to the Atlantic seaboard of North America. Nonetheless, questions about the connectivity and temporal continuity of mammoth populations and species remain unanswered. We use a combination of targeted enrichment and high-throughput sequencing to assemble and interpret a data set of 143 mammoth mitochondrial genomes, sampled from fossils recovered from across their Holarctic range. Our dataset includes 54 previously unpublished mitochondrial genomes and significantly increases the coverage of the Eurasian range of the species. The resulting global phylogeny confirms that the Late Pleistocene mammoth population comprised three distinct mitochondrial lineages that began to diverge ~1.0–2.0 million years ago (Ma). We also find that mammoth mitochondrial lineages were strongly geographically partitioned throughout the Pleistocene. In combination, our genetic results and the pattern of morphological variation in time and space suggest that male-mediated gene flow, rather than large-scale dispersals, was important in the Pleistocene evolutionary history of mammoths.

During the Holocene, bison (Bison bison) were key components of the Great Plains landscape. This study utilizes serial stable isotope analyses (tooth enamel carbonate) of 29 individuals from five middle Holocene (∽ 7–8.5·ka) archaeological sites to address seasonal variability in movement patterns and grazing behavior of bison populations in the eastern Great Plains. Stable carbon isotopes (δ13C) indicate a bison diet that is similar to the C3/C4 composition of modern tallgrass prairies, while 87Sr/86Sr values generally indicate very little seasonal movement (b50 km) and relatively limited inter-annual movement (b500 km) over the course of 4–5 yr. Analyses of variability in serial stable oxygen isotope samples (δ18O) further substantiate a model of localized bison herds that adhered to upland areas of the eastern Plains and prairie–forest border.

After evolving in Africa at the close of the Miocene, mammoths (Mammuthus sp.) spread through much of the northern hemisphere, diversifying morphologically as they entered various habitats. Paleontologically, these morphs are conventionally recognized as species. In Pleistocene North America alone, several mammoth species have been recognized, inhabiting environments as different as cold tundrasteppe in the north and the arid grasslands or temperate savanna-parklands of the south. Yet mammoth phylogeographic studies have overwhelmingly focused on permafrost-preserved remains of only one of these species, Mammuthus primigenius (woolly mammoth). Here we challenge this bias by performing a geographically and taxonomically wide survey of mammoth genetic diversity across North America. Using a targeted enrichment technique, we sequenced 67 complete mitochondrial genomes including non-primigenius specimens representing Mammuthus columbi (Columbian mammoth), Mammuthus jeffersonii (Jeffersonian mammoth), and Mammuthus exilis (pygmy mammoth), including specimens from contexts not generally associated with good DNA preservation. While we uncovered clear phylogeographic structure in mammoth matrilines, their phylogeny as recovered from mitochondrial DNA is not compatible with existing systematic interpretations of their paleontological record. Instead, our results strongly suggest that various nominal mammoth species interbred, perhaps extensively. We hypothesize that at least two distinct stages of interbreeding between conventional paleontological species are likely responsible for this pattern-one between Siberian woolly mammoths and resident American populations that introduced woolly mammoth phenotypes to the Enk et al. Mammoth Evolutionary History in North America continent, and another between ecomorphologically distinct populations of woolly and Columbian mammoths in North America south of the ice.