Uniparental Markers of Contemporary Italian Population Reveals Details on Its Pre-Roman Heritage

BackgroundAccording to archaeological records and historical documentation, Italy has been a melting point for populations of different geographical and ethnic matrices. Although Italy has been a favorite subject for numerous population genetic studies, genetic patterns have never been analyzed comprehensively, including uniparental and autosomal markers throughout the country. Methods/Principal FindingsA total of 583 individuals were sampled from across the Italian Peninsula, from ten distant (if homogeneous by language) ethnic communities — and from two linguistic isolates (Ladins, Grecani Salentini). All samples were first typed for the mitochondrial DNA (mtDNA) control region and selected coding region SNPs (mtSNPs). This data was pooled for analysis with 3,778 mtDNA control-region profiles collected from the literature. Secondly, a set of Y-chromosome SNPs and STRs were also analyzed in 479 individuals together with a panel of autosomal ancestry informative markers (AIMs) from 441 samples. The resulting genetic record reveals clines of genetic frequencies laid according to the latitude slant along continental Italy – probably generated by demographical events dating back to the Neolithic. The Ladins showed distinctive, if more recent structure. The Neolithic contribution was estimated for the Y-chromosome as 14.5% and for mtDNA as 10.5%. Y-chromosome data showed larger differentiation between North, Center and South than mtDNA. AIMs detected a minor sub-Saharan component; this is however higher than for other European non-Mediterranean populations. The same signal of sub-Saharan heritage was also evident in uniparental markers. Conclusions/SignificanceItaly shows patterns of molecular variation mirroring other European countries, although some heterogeneity exists based on different analysis and molecular markers. From North to South, Italy shows clinal patterns that were most likely modulated during Neolithic times.背景 根据考古记录与历史文献记载，意大利始终是汇聚不同地理起源与族群背景人群的融合熔炉。尽管意大利已成为众多人群遗传学研究的热门主题，但此前尚未针对该国全境的单亲遗传标记与常染色体标记开展全面的遗传模式分析。 方法/主要研究结果 本研究从意大利半岛全境的10个语言同质化的偏远族群社区，以及2个语言隔离群体（拉登人（Ladins）、萨伦托希腊人（Grecani Salentini））中，共采集583份个体样本。首先对所有样本进行线粒体DNA（mtDNA）控制区及选定编码区单核苷酸多态性（mtSNPs）分型，并将该数据集与从公开文献中收集的3778条mtDNA控制区序列资料合并分析。其次，对479份样本开展Y染色体单核苷酸多态性（Y-SNPs）与短串联重复序列（Y-STRs）分型，并对441份样本进行一组常染色体祖先信息标记（AIMs）检测。 最终得到的遗传数据显示，意大利大陆范围内的遗传频率沿纬度方向呈现渐变分布，该模式大概率由新石器时代的人口事件塑造。拉登人群体虽形成时间较晚，但展现出独特的遗传结构。研究估算得出，Y染色体中来自新石器时代的遗传贡献占比为14.5%，mtDNA中则为10.5%。Y染色体数据显示，意大利北部、中部与南部人群间的遗传分化程度高于mtDNA数据所反映的结果。常染色体祖先信息标记检测到少量撒哈拉以南非洲血统组分，不过该占比高于其他欧洲非地中海人群。单亲遗传标记中同样显现出撒哈拉以南非洲遗传背景的信号。 结论与意义 尽管基于不同分析方法与分子标记会观察到一定的异质性，但意大利的分子变异模式与其他欧洲国家整体相似。从北至南，意大利人群的遗传变异呈现渐变模式，这一特征大概率在新石器时代便已形成。