European Neolithization and Ancient DNA: An Assessment

Abstract

Neolithic processes underlying the distribution of genetic diversity among European populations have been the subject of intense debate since the first genetic data became available. However, patterns observed in the current European gene pool are the outcome of Paleolithic and Neolithic processes, overlaid with four millennia of further developments. This observation encouraged paleogeneticists to contribute to the debate by directly comparing genetic variation from the ancient inhabitants of Europe to their contemporary counterparts. Pre-Neolithic and Neolithic paleogenetic data are becoming increasingly available for north and northwest European populations. Despite the numerous problems inherent in the paleogenetic approach, the accumulation of ancient DNA datasets offers new perspectives from which to interpret the interactions between hunter-gatherer and farming communities. In light of information emerging from diverse disciplines, including recent paleogenetic studies, the most plausible model explaining the movement of Neolithic pioneer groups in central Europe is that of leapfrog migration.

Demographic Events and Evolutionary Forces Shaping European Genetic Diversity

“…Generally, it appears there is substantial discontinuity between both Paleolithic and Neolithic as well as (though to a lesser extent) Neolithic and modern mtDNA pools in central and northern Europe (Bramanti et al 2009;Malmström et al 2009;Haak et al 2010). There has, therefore, likely been significant postNeolithic reshaping of European maternal lineages (e.g., during the metal ages) (Deguilloux et al 2012), although greater mtDNA Neolithic continuity has been observed in Western Europe (Sampietro et al 2007;Lacan et al 2011).…”

Ancient DNA: A Window to the Past of Europe

“…In concert with the limited number of well-documented archaeological specimens available for analyses, this point automatically leads to a low representativeness of samples that can yield reliable results. There are still only a limited number of aDNA samples; for example, a total of 100 Neolithic farmers' and 14 Mesolithic huntergatherers' mitochondrial sequences have been obtained to date, and it is obvious that such samples will not permit the complete resolution of the debate surrounding Neolithisation processes [6] . However, even this small sample size begins to shed some light on these processes in some specific regions, as we will see, and the continuous improvement of the aDNA database will doubtlessly provide critical insight into this topic.…”

“…However, because of the complexity of population dynamics in Europe, the extent to which the present-day genetic pattern can be attributed to the key episodes previously presented is still unclear. For example, genetic studies have delivered numerous, but often conflicting, inferences on the impact of Neolithisation on the modern European gene pool [see 6 for a review]. Indeed, even if geneticists now agree that the Neolithic farmers participated in the construction of the European gene pool, the importance of this Neolithic contribution remains unclear, and it can vary from 20 to 70% according to the genetic markers analysed or the analytical methods used [see 7-10 , for example].…”

Thinking Across the African Past: Interdisciplinarity and Early History

“…However, the extent to which inferences from modern populations about the past genetic variation are correct can only be assessed by studies of ancient DNA. Despite its acknowledged limitations, paleogenetics has been enormously influential in shaping the debates about Neolithization processes in Europe and investigating hypotheses about population continuity vs. discontinuity (Soares et al 2010;DeGuilloux et al 2012). By contrast, paleogenetics is still rare in Africa outside of Egypt.…”

“…This debate stimulated more genetic studies, new critiques, and the addition of paleogenetic studies of DNA from both Neolithic and huntergatherer human remains dated to the period 5500-2500 cal BCE. We now know that the process of Neolithization was vastly more complex, involving colonization by farmers in a leapfrog fashion, local adoption of farming by hunter-gatherers via contacts with colonizers, gene replacement that favored the indigenous huntergatherers, and a significant amount of local variation in these processes (the forgoing summarizes a number of points in Deguilloux et al 2012). In Europe, the interaction of archaeology, genetics, and paleogenetics has produced results at the mesoscale, where regional and in some cases local patterns can be detected.…”