On the chronology of the Uluzzian.

The Uluzzian, one of Europe's 'transitional' technocomplexes, has gained particular significance over the past three years when the only human remains associated with it were attributed to modern humans, instead of Neanderthals as previously thought. The position of the Uluzzian at stratified sequences, always overlying late Mousterian layers and underlying early Upper Palaeolithic ones, highlights its significance in understanding the passage from the Middle to Upper Palaeolithic, as well as the replacement of Neanderthals by modern humans in southeastern Mediterranean Europe. Despite several studies investigating aspects of its lithic techno-typology, taxonomy and material culture, the Uluzzian chronology has remained extremely poorly-known, based on a handful of dubious chronometric determinations. Here we aim to elucidate the chronological aspect of the technocomplex by presenting an integrated synthesis of new radiocarbon results and a Bayesian statistical approach from four stratified Uluzzian cave sequences in Italy and Greece (Cavallo, Fumane, Castelcivita and Klissoura 1). In addition to building a reliable chronological framework for the Uluzzian, we examine its appearance, tempo-spatial spread and correlation to previous and later Palaeolithic assemblages (Mousterian, Protoaurignacian) at the relevant regions. We conclude that the Uluzzian arrived in Italy and Greece shortly before 45,000 years ago and its final stages are placed at ∼39,500 years ago, its end synchronous (if not slightly earlier) with the Campanian Ignimbrite eruption.

A revised timescale for human evolution based on ancient mitochondrial genomes.

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. RESULTS: Here, we use mitochondrial genome sequences from ten 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) that occurred less than 62-95 kya. CONCLUSIONS: Though single loci like mitochondrial DNA (mtDNA) can only provide biased estimates of population divergence times, they can provide valid upper bounds. Our results exclude most of the older dates for African and non-African population divergences recently suggested by de novo mutation rate estimates in the nuclear genome.