Dipartimento di Scienze della Vita e Biotecnologie, Università di Ferrara, Ferrara, Italy.
Dipartimento di Biologia, Università di Firenze, Florence, Italy.
Am J Phys Anthropol. 2018 Nov;167(3):497-506. doi: 10.1002/ajpa.23679. Epub 2018 Sep 6.
With the advent of ancient DNA analyses, it has been possible to disentangle the contribution of ancient populations to the genetic pool of the modern inhabitants of many regions. Reconstructing the maternal ancestry has often highlighted genetic continuity over several millennia, but almost always in isolated areas. Here we analyze North-western Tuscany, a region that was a corridor of exchanges between Central Italy and the Western Mediterranean coast.
We newly obtained mitochondrial HVRI sequences from 28 individuals, and after gathering published data, we collected genetic information for 119 individuals from the region. Those span five periods during the last 5,000 years: Prehistory, Etruscan age, Roman age, Renaissance, and Present-day. We used serial coalescent simulations in an approximate Bayesian computation framework to test for continuity between the mentioned groups.
Our analyses always favor continuity over discontinuity for all groups considered, with the Etruscans being part of the genealogy. Moreover, the posterior distributions of the parameters support very small female effective population sizes.
The observed signals of long-term genetic continuity and isolation are in contrast with the history of the region, conquered several times (Etruscans, Romans, Lombards, and French). While the Etruscans appear as a local population, intermediate between the prehistoric and the other samples, we suggest that the other conquerors-arriving from far-had a consistent social or sex bias, hence only marginally affecting the maternal lineages. At the same time, our results show that long-term genealogical continuity is not necessarily linked to geographical isolation.
随着古 DNA 分析的出现，人们有可能厘清古代人群对许多地区现代居民遗传库的贡献。重建母系祖先的遗传结构往往突出了几千年来的遗传连续性，但这种连续性几乎总是出现在孤立的地区。在这里，我们分析了西北托斯卡纳地区，该地区是意大利中部和西地中海沿岸之间交流的走廊。
我们从 28 个人中获得了线粒体 HVRI 序列，在收集了已发表的数据后，我们从该地区收集了 119 个人的遗传信息。这些信息跨越了过去 5000 年的五个时期：史前时期、伊特鲁里亚时期、罗马时期、文艺复兴时期和现代时期。我们使用连续合并模拟在近似贝叶斯计算框架中，检验了上述群体之间的连续性。
我们的分析始终倾向于所有考虑的群体之间的连续性而非不连续性，伊特鲁里亚人是家谱的一部分。此外，参数的后验分布支持非常小的女性有效种群大小。
观察到的长期遗传连续性和隔离的信号与该地区的历史形成鲜明对比，该地区曾多次被征服（伊特鲁里亚人、罗马人、伦巴第人和法国人）。虽然伊特鲁里亚人似乎是一个介于史前和其他样本之间的本地人群，但我们认为，来自远方的其他征服者——有着一致的社会或性别偏见，因此只对母系血统产生了轻微的影响。同时，我们的结果表明，长期的谱系连续性不一定与地理隔离有关。
