Throughout the past few years, a lively debate emerged about the timing and magnitude of the human migrations between the Iberian Peninsula and the Maghreb. Several pieces of evidence, including archaeological, anthropological, historical, and genetic data, have pointed to a complex and intermingled evolutionary history in the western Mediterranean area. To study to what extent connections across the Strait of Gibraltar and surrounding areas have shaped the present-day genomic diversity of its populations, we have performed a screening of 2.5 million single-nucleotide polymorphisms in 142 samples from southern Spain, southern Portugal, and Morocco. We built comprehensive data sets of the studied area and we implemented multistep bioinformatic approaches to assess population structure, demographic histories, and admixture dynamics. Both local and global ancestry inference showed an internal substructure in the Iberian Peninsula, mainly linked to a differential African ancestry. Western Iberia, from southern Portugal to Galicia, constituted an independent cluster within Iberia characterized by an enriched African genomic input. Migration time modeling showed recent historic dates for the admixture events occurring both in Iberia and in the North of Africa. However, an integrative vision of both paleogenomic and modern DNA data allowed us to detect chronological transitions and population turnovers that could be the result of transcontinental migrations dating back from Neolithic times. The present contribution aimed to fill the gaps in the modern human genomic record of a key geographic area, where the Mediterranean and the Atlantic come together.

中文翻译：

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人类基因组多样性，地中海与大西洋的交汇处。

在过去的几年中，围绕伊比利亚半岛和马格里布之间的人类迁徙的时间和规模展开了激烈的辩论。包括考古，人类学，历史和遗传数据在内的几项证据指出了地中海西部地区复杂而混杂的进化史。为了研究直布罗陀海峡与周边地区之间的联系在多大程度上影响了当今人口的基因组多样性，我们从西班牙南部，葡萄牙南部和摩洛哥的142个样本中筛选了250万个单核苷酸多态性。我们建立了研究区域的综合数据集，并实施了多步生物信息学方法来评估人口结构，人口历史和混合动力。本地和全球血统的推论都显示了伊比利亚半岛的内部子结构，这主要与非洲血统的差异有关。从葡萄牙南部到加利西亚的伊比利亚西部地区构成了伊比利亚境内的一个独立集群，其特征是丰富的非洲基因组输入。迁移时间模型显示了伊比利亚和非洲北部发生的外加剂事件的近期历史日期。然而，对古基因组学和现代DNA数据的综合观察使我们能够发现时间变化和人口更替，这可能是新石器时代以来跨大陆迁移的结果。本文稿旨在填补地中海和大西洋融合在一起的关键地理区域的现代人类基因组记录中的空白。