Summary Background Recent analyses of de novo DNA mutations in modern humans have suggested a nuclear substitution rate that is approximately half that of previous estimates based on fossil calibration. This result has led to suggestions that major events in human evolution occurred far earlier than previously thought. Result Here we use mitochondrial genome sequences from 10 securely dated ancient modern humans spanning 40,000 years as calibration points for the mitochondrial clock, thus yielding a direct estimate of the mitochondrial substitution rate. Our clock yields mitochondrial divergence times that are in agreement with earlier estimates based on calibration points derived from either fossils or archaeological material. In particular, our results imply a separation of non-Africans from the most closely related sub-Saharan African mitochondrial DNAs (haplogroup L3) of less than 62,000-95,000 years ago. Conclusion Though single loci like mitochondrial DNA (mtDNA) can only provide biased estimates of population split times, they can provide valid upper bounds; our results exclude most of the older dates for African and non-African split times recently suggested by de novo mutation rate estimates in the nuclear genome.

The geographic and temporal origins of the domestic dog remain controversial, as genetic data suggest a domestication process in East Asia beginning 15,000 years ago, whereas the oldest doglike fossils are found in Europe and Siberia and date to >30,000 years ago. We analyzed the mitochondrial genomes of 18 prehistoric canids from Eurasia and the New World, along with a comprehensive panel of modern dogs and wolves. The mitochondrial genomes of all modern dogs are phylogenetically most closely related to either ancient or modern canids of Europe. Molecular dating suggests an onset of domestication there 18,800 to 32,100 years ago. These findings imply that domestic dogs are the culmination of a process that initiated with European hunter-gatherers and the canids with whom they interacted.

The Bonn-Oberkassel dog remains (Upper Pleistocene and 14223 þ-58 years old) have been reported more than 100 years ago. Recent re-examination revealed the tooth of another older and smaller dog, making this domestic dog burial not only the oldest known, but also the only one with remains of two dogs. This observation brings the total known Magdalenian dogs to nine. Domestication of dogs during the final Palaeolithic has important implications for understanding pre-Holocene hunter-gatherers. Most proposed hunter-gatherer motivations for domesticating dogs have been utilitarian. However, remains of the Bonn-Oberkassel dogs may offer another view. The Bonn-Oberkassel dog was a late juvenile when it was buried at approximately age 27e28 weeks, with two adult humans and grave goods. Oral cavity lesions indicate a gravely ill dog that likely suffered a morbillivirus (canine distemper) infection. A dental line of suggestive enamel hypoplasia appears at the 19-week developmental stage. Two additional enamel hypoplasia lines, on the canine only, document further disease episodes at weeks 21 and 23. Pathological changes also include severe periodontal disease that may have been facilitated by immunodeficiency. Since canine distemper has a three-week disease course with very high mortality, the dog must have been perniciously ill during the three disease bouts and between ages 19 and 23 weeks. Survival without intensive human assistance would have been unlikely. Before and during this period, the dog cannot have held any utilitarian use to humans. We suggest that at least some Late Pleistocene humans regarded dogs not just materialistically, but may have developed emotional and caring bonds for their dogs, as reflected by the survival of this dog, quite possibly through human care.

Dogs are known to be the oldest animals domesticated by humans. Although many studies have examined wolf domestication, the geographic and temporal origin of this process is still being debated. To address this issue, our study sheds new light on the early stages of wolf domestication during the Magdalenian period (16–14 ka cal BP) in the Hegau Jura region (Southwestern Germany and Switzerland). By combining morphology, genetics, and isotopes, our multidisciplinary approach helps to evaluate alternate processes driving the early phases of domestication. The isotope analysis uncovered a restricted, low δ15N protein diet for all analyzed Gnirshöhle specimens, while morphological examinations and phylogenetic relationships did not unequivocally assign them to one or the other canid lineage. Intriguingly, the newly generated mitochondrial canid genomes span the entire genetic diversity of modern dogs and wolves. Such high mitochondrial diversity could imply that Magdalenian people tamed and reared animals originating from different wolf lineages. We discuss our results in light of three ecological hypotheses and conclude that both domestication and the existence of a specialized wolf ecomorph are highly probable. However, due to their proximity to humans and a restricted diet, we propose domestication as the most likely scenario explaining the patterns observed herein.