The effect of the Neolithic expansion on European molecular diversity

[Nadvojvoda Janez Kranjski]

The effect of the Neolithic expansion on European molecular diversity

We performed extensive and realistic simulations of the colonization process of Europe by Neolithic farmers, as well as their potential admixture and competition with local Palaeolithic hunter-gatherers. We find that minute amounts of gene flow between Palaeolithic and Neolithic populations should lead to a massive Palaeolithic contribution to the current gene pool of Europeans. This large Palaeolithic contribution is not expected under the demic diffusion (DD) model, which postulates that agriculture diffused over Europe by a massive migration of individuals from the Near East. However, genetic evidence in favour of this model mainly consisted in the observation of allele frequency clines over Europe, which are shown here to be equally probable under a pure DD or a pure acculturation model. The examination of the consequence of range expansions on single nucleotide polymorphism (SNP) diversity reveals that an ascertainment bias consisting of selecting SNPs with high frequencies will promote the observation of genetic clines (which are not expected for random SNPs) and will lead to multimodal mismatch distributions. We conclude that the different patterns of molecular diversity observed for Y chromosome and mitochondrial DNA can be at least partly owing to an ascertainment bias when selecting Y chromosome SNPs for studying European populations.

STUDY: http://www.mathiascurrat.com/pdf/cur...er_prsl_05.pdf

[Nadvojvoda Janez Kranjski]

[Nadvojvoda Janez Kranjski]

Founder analysis is a method for analysis of nonrecombining DNA sequence data, with the aim of identification and dating of migrations into new territory. The method picks out founder sequence types in potential source populations and dates lineage clusters deriving from them in the settlement zone of interest. Here, using mtDNA, we apply the approach to the colonization of Europe, to estimate the proportion of modern lineages whose ancestors arrived during each major phase of settlement. To estimate the Palaeolithic and Neolithic contributions to European mtDNA diversity more accurately than was previously achievable, we have now extended the Near Eastern, European, and northern-Caucasus databases to 1,234, 2,804, and 208 samples, respectively. Both back-migration into the source population and recurrent mutation in the source and derived populations represent major obstacles to this approach. We have developed phylogenetic criteria to take account of both these factors, and we suggest a way to account for multiple dispersals of common sequence types. We conclude that (i) there has been substantial back-migration into the Near East, (ii) the majority of extant mtDNA lineages entered Europe in several waves during the Upper Palaeolithic, (iii) there was a founder effect or bottleneck associated with the Last Glacial Maximum, 20,000 years ago, from which derives the largest fraction of surviving lineages, and (iv) the immigrant Neolithic component is likely to comprise less than one-quarter of the mtDNA pool of modern Europeans.


Download study here: http://evolutsioon.ut.ee/publications/Richards2000.pdf

[Agrippa]

The most interesting idea seems to be that Neolithic markers should be STRONGER in NW-Europe than in the Eastern Mediterranean. So does this mean (Table 5) that every kind of movement in THIS TIME is being described? Than it would be logical because the basic change in lines should be less strong in the region from which the Neolithic expansion originated from...

[Nadvojvoda Janez Kranjski]

So does this mean (Table 5) that every kind of movement in THIS TIME is being described?

Mapped out are genetic contributions that were new (different from the old) at a certain period of time, such as haplogroups J and E3b (well, this report is about mtDNA).

[Agrippa]

Originally Posted by Nadvojvoda Janez Kranjski

Mapped out are genetic contributions that were new (different from the old) at a certain period of time, such as haplogroups J and E3b (well, this report is about mtDNA).

Ok, than its clear, like I thought everything "new" to the regions in question. So would a movement from Europe to Asia Minor in the Neolithicum be a "Neolithic marker" in this study too?