Demographic Histories, Isolation and Social Factors as Determinants of the Genetic Structure of Alpine Linguistic Groups

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 Combining unpublished and literature data on Y chromosome and mitochondrial variation, we were able to detect different genetic patterns.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.

Culturural and Language Aspects and the Problem of Regional Disintegration. The Case of Italy

“…presented Conclusions of this work [3] are in good agreement with the analysis carried out in the paper [20], where the relationship between genetic and linguistic diversification in human populations of Italy has been explored to interpret some specific issues in its history.…”

“…In poor quarters as the profit is got from the affairs which are on the verge of the law, or illegal [1]. The researcher Italo Talia writes that the given conclusions can be extended to four main areas of the South (Naples, Palermo, Catania and Bari) and not only on the poorest areas, but also on a wide spectrum of surrounding territories where borders of the homogeneous closely bound cultural landscape are filled by the new identity which is not neither rural, nor city [20].…”

Traces of forgotten historical events in mountain communities in Central Italy: A genetic insight

“…Small communities scattered in rugged geographical and sparsely populated areas share features typical to all mountain communities, which could account for their low genetic intrapopulation diversity, mainly because of founder effects. This condition seems to be common to other isolated groups such as the linguistic islands of the eastern Alps, where small size coupled with stable genetic isolation has allowed them to maintain their linguistic and genetic identity (Babalini et al, ; Coia et al, ; Capocasa et al, ). The high endogamy common to human communities living in mountainous regions results in low genetic variation (Babalini et al, ; Cardoso et al, ).…”

The female ancestor's tale: Long‐term matrilineal continuity in a nonisolated region of Tuscany

“…In turn, this observation means that there is no necessary link between genealogical continuity and presence of obvious barriers to gene flow. It is a fact that, whenever populations are isolated by physical (Coia et al, ; Rosser et al, ) or cultural (Barbujani & Sokal, ; Longobardi et al, ) barriers, they tend to diverge genetically from their neighbors because of drift. However, the population of the current Lucca province appears to have retained very ancient mitochondrial features, despite occupying a geographical corridor between the Ligurian and the Tyrrhenian coast, and despite not showing the persistence of unique cultural traits through the centuries.…”