32 RIMANTAS JANKAUSKAS Ancient Mitochondrial Dna from Stone age Lithuania and the Possible Origins of the First Inhabitants Introduction Europe as a subcontinent has witnessed several dramat- ic changes in archaeological cultures and population since since anatomically modern humans displaced the Neanderthal population around 30,000 to 40,000 years ago. Palaeolithic hunter-gatherers survived the Last Glacial Maximum (LGM) about 25,000 years ago in southern and eastern refugia (Richards et al. 1996; Torroni et al. 2001), and resettled Central and Eastern Europe following the retreat of the ice sheets. With the end of the Ice Age ~9600 BC, their Late Palaeolithic and Mesolithic descendants or successors recolonised large parts of the deglaciated northern latitudes. Start- ing in 7000 BC, the Mesolithic way of life of hunting, gathering and fishing was rapidly or gradually replaced by the Stone Age farming cultures. Several major pro- cesses (initial Palaeolithic colonisation, recolonisation after the LGM and Younger Dryas cold relapse, the spread of the Neolithic, and possible small-scale mi- grations in the Eneolithic age) could have left traces on the modern European gene pool (Barbujani, Bertorelle 2001; Soares et al. 2010). The potential impact of such transitions on the genetic ancestry of modern Europe- ans has been extensively debated (Cavalli-Sforza et al. 1994; Richards et al. 1996; Sampietro et al. 2007). The application of ancient DNA studies added new stimu- lus to these discussions, as archaeogenetic research can help in reconstructing details of demographic history (Renfrew 2010), and mitochondrial DNA (mtDNA) at present is considered to be the most informative ge- netic marker system for studying European prehistory (Soares et al. 2010). Some investigations have shown that early Central European farmers had a very limited genetic impact on the present European mtDNA pool (Haak et al. 2005; Burger et al. 2006). However, it ap- pears that there cannot be a universal ‘pan-European’ model of cultural and population-biologic processes, as each climato-geographic region could have its own specificity (Zvelebil 1998), and populations are likely to differ in their history and genetic composition. Dur- ing the last few years, advances in ancient DNA studies have provided a rapidly growing amount of data that serves as a basis for the verification or creation of new hypotheses, and also on a regional level, in our case, the eastern Baltic area (Bramanti et al. 2009). In this paper, we will attempt to summarise available relevant mtDNA data, and to discuss their impact on possible trends for future research. ANCIENT MITOCHONDRIAL DNA FROM STONE AGE LITHUANIA AND THE POSSIBLE ORIGINS OF THE FIRST INHABITANTS RIMANTAS JANKAUSKAS Abstract This paper discusses recently published data on mitochondrial DNA (mtDNA) extracted from Stone Age burials in Lithuania in a broader European context, and data from modern Lithuanians on the basis of recent literature. Several major processes (initial Palaeolithic colonisation, recolonisation after the LGM and Younger Dryas cold relapse, the spread of the Neolithic, and possible small-scale migrations in the Eneolithic age) could have left traces on the modern gene pool. From four Lithu- anian samples where data on mtDNA were available, one (Spiginas 4) belonged to haplogroup U4, and three (Donkalnis 1, and Kretuonas 1 and 3) to U5b2. In total, out of 17 individuals from Central and East European non-farming cultures (Meso- lithic and Neolithic Ceramic, spanning a period from circa 7800 BC to 2300 BC), a majority of them had mtDNA type ‘U’. An exceptionally high incidence of U5-types (more than 45%) occurs among the modern Saami (Lapps) of northern Scandinavia, perhaps the closest modern European equivalent of Mesolithic hunter-gatherers. Genetic time estimates based on modern mtDNA have suggested that the U5-type arose by mutation about 50,000 to 40,000 years BP. This age implies that around the glacial maximum 20,000 years BP, U5 types were already present and could have repopulated Central and northern Europe as soon as northern areas were deglaciated. Both western (Franco-Cantabrian) and eastern (Pontic) refugia could be sources of this repopulation. In the recent Lithuanian population, U5 and U4 haplogroups are infrequent. The mtDNA homogeneity observed across modern Europe is a more recent phenomenon, less than 7,000 years old, according to these ancient mtDNA results. We can refer to the third millennium BC, internal European migrations from the Eneolithic that significantly modified the genetic landscape, as a time window little explored by archaeogeneticists. The imprecise chronology of mtDNA mutations should in the first instance be based on audited archaeological sources. Key words: mtDNA, U5 haplogroup, Stone Age, Lithuania.