U152 and Ligures – Bertoncini et al. (2012)

By Richard Rocca

Bertoncini et al. (2012) A Y Variant Which Traces the Genetic Heritage of Ligures Tribes. Journal of Biological Research, Vol.84, No.1 2012.

This is the first published attempt that tries to fit U152 into an archeaological timeframe and setting. The authors set out to see if there was a Y-DNA correlation between the areas once inhabited by the Lugures Apuani in Northern Italy and Sannio in Southern Italy, where the Romans deported the Ligurians en masse as per classic historians. They found that U152(xL2) made up 51.8% in the Apuan Alps of Northern Italy with a frequency peak of 77.8% in the town of Pruno. The combined U152(xL2) and L2 frequencies surpass the overall U152 frequency of U152 in Brescia (51.3%, Boattini et al. 2013) and Badia (50%, Coia et al 2013). Certainly the Apuan U152 has more in common with Brescian U152, as it is also made up largely of U152(xL2), whereas Badian U152 is almost entirely derived at L2. Furthermore, the authors state that U152(xL2) makes up almost the entirety of M269 in the Apuan Alps and that U152’s subclade L2 is poorly represented there. Based on STR diversity, the authors were not able to prove or disprove the deportation, nor get a sense of the direction of geneflow.

From limited consumer testing, it is likely that an important amount of U152(xL2) from the central Alps to Tuscany is made up of the Z36 subclade. Z36 has also been shown to be the largest U152 subclade in a small village outside of Florence, Tuscany (Rocca et al. 2012). While the authors date the TMRCA of U152(xL2) to the Urnfield Cultural time period, it could be that this was a time when U152 subclades, in general, expanded significantly and not necessarily their origination point. The mention of the Canegrate and Proto-Golasecca Cultures may be a good representation of where U152(xL2) and its sublcades were frequent during the late Bronze Age.

See also: Capocasa et al. (2014) Linguistic, geographic and genetic isolation: a collaborative study of Italian populations (ahead of print)

The hypothesis of a genetic legacy between Ligures Apuani and present Apuan and Samnite isolates (Ligures Legacy Model, LLM) was tested by the RU of the University of Pisa through the genetic characterization of uni-linear markers in a sample of unrelated donors from the communities of Vagli (Province of Lucca) and Circello (Province of Benevento) selected according to founder surnames. Vagli is located in the core of the area which has many archeological records linked to Ligures Apuani. Its elder inhabitants still speak a language characterized by a number of linguistic relicts (Ambrosi, 1956; Guazzelli, 2001). Circello lays in close proximity to the remains of Macchia, the town in the Samnium around which the deported Ligures (L. Baebiani) were forced to settle in 180 BC (Patterson, 2009).

A slight reduction of HD at both mtDNA and Y Chromosome has been observed for Vagli (0.948 and 0.984) and Circello (0.960 and 0.975) relative to the neighbouring populations of Piana di Lucca (0.983 and 0.999) and Benevento (0.989 and 1.000). As expected for communities of Indo-European ancestry, usually practicing prevalence of female vs male mobility (patrilocal), genetic distances based on mtDNA are weaker discriminators than distances based on MSY haplotypes (see Supplementary Tab. S1). Preliminary comparative assessments of MSY profiles suggest that the diversity of Apuans might be due to an excess of R-U152 haplotypes, whose diffusion in Italy is thought to coincide with the diffusion of Ligures cultural features in the Middle-Late Bronze Age (Bertoncini et al., 2012).

As a whole, the two communities under study (Vagli and Circello) showed a genetic pattern which is compatible with a long history of isolation but also with quite diverging microevolutionary histories after contacts implied by the LLM. As a more direct test of a genetic continuum with Ligures tribes (Fig. 4), we assessed whether an enrichment of matches compatible with the Titus Livius deportation hypothesis is detectable when comparing any MSY haplotype of the local population (Vagli) with haplotypes of both, the putative displaced (Circello) and the open Samnite population (Benevento). The enrichment of LLM-compatible matches in the Vagli-Circello curve totaled about 80% and was extremely statistically significant (Fisher exact test, p<0.0001).

The hypothesis of direct descent of the resident males in the Apuan and in the Circello area from members of Ligures tribes, who escaped deportation, cannot be ruled out. Further data from wider samples and haplogroup diagnostic markers, as well as more extensive simulation analyses will help achieve more robust inferences. Nonetheless, our case study shows that even mild geographical and cultural isolation may lead to the preservation of a long genetic thread connecting present populations to ancient layers of pre-Roman Italy. As a corollary, it suggests that many isolated Italian communities other than Northern Apennine ones may escape simplistic classification schemes (i.e. linguistic vs geographic isolate), owing to the gradual fringing and recent oblivion of a common ancient cultural identity. Finally, our study highlights the usefulness of accurate non random genetic samplings to uncover genetic layers obscured by recent reshufflings within and among human populations.

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