Demographic histories, isolation and social factors as determinants of the genetic structure of Alpine linguistic groups

PLoS One. 2013 Dec 2;8(12):e81704. doi: 10.1371/journal.pone.0081704. eCollection 2013.

Abstract

Great European mountain ranges have acted as barriers to gene flow for resident populations since prehistory and have offered a place for the settlement of small, and sometimes culturally diverse, communities. Therefore, the human groups that have settled in these areas are worth exploring as an important potential source of diversity in the genetic structure of European populations. In this study, we present new high resolution data concerning Y chromosomal variation in three distinct Alpine ethno-linguistic groups, Italian, Ladin and German. Combining unpublished and literature data on Y chromosome and mitochondrial variation, we were able to detect different genetic patterns. In fact, within and among population diversity values observed vary across linguistic groups, with German and Italian speakers at the two extremes, and seem to reflect their different demographic histories. Using simulations we inferred that the joint effect of continued genetic isolation and reduced founding group size may explain the apportionment of genetic diversity observed in all groups. Extending the analysis to other continental populations, we observed that the genetic differentiation of Ladins and German speakers from Europeans is comparable or even greater to that observed for well known outliers like Sardinian and Basques. Finally, we found that in south Tyroleans, the social practice of Geschlossener Hof, a hereditary norm which might have favored male dispersal, coincides with a significant intra-group diversity for mtDNA but not for Y chromosome, a genetic pattern which is opposite to those expected among patrilocal populations. Together with previous evidence regarding the possible effects of "local ethnicity" on the genetic structure of German speakers that have settled in the eastern Italian Alps, this finding suggests that taking socio-cultural factors into account together with geographical variables and linguistic diversity may help unveil some yet to be understood aspects of the genetic structure of European populations.

Publication types

  • Historical Article

MeSH terms

  • Chromosomes, Human, Y / genetics*
  • Demography / history*
  • Ethnicity / genetics
  • Ethnicity / history
  • Evolution, Molecular
  • Female
  • Gene Flow*
  • Genetic Variation*
  • History, 15th Century
  • History, 16th Century
  • History, 17th Century
  • History, 18th Century
  • History, 19th Century
  • History, 20th Century
  • History, 21st Century
  • Humans
  • Linguistics*
  • Male
  • Mitochondria / genetics
  • Polymorphism, Single Nucleotide
  • White People / ethnology
  • White People / genetics*
  • White People / history*

Grants and funding

The study of Ladins, Italian speaking populations and Cimbri from Luserna was granted by the Autonomous Province of Trento (bando post-doc 2006 to VC) and by the Autonomous Province of Bolzano/Bozen (Ripartizione Diritto allo Studio, Università e Ricerca Scientifica, Incoming Research to VC). Research work among German speaking groups from Friuli and Veneto regions was supported from funds to GDB by the Ministero della Ricerca Scientifica (Progetti di Ricerca di interesse nazionale 2007-2009, prot.n. 2007TYXE3X), the University of Rome "La Sapienza" (project "L’isolamento genetico in popolazioni europee", prot. no. C26A117JKC and C26A12LMMA) and the Italian Institute of Anthropology (project Atlante bioculturale Italiano). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.