Survival of Late Pleistocene Hunter-Gatherer Ancestry in the Iberian Peninsula

The Iberian Peninsula in southwestern Europe represents an important test case for the study of human population movements during prehistoric periods. During the Last Glacial Maximum (LGM) the peninsula formed a periglacial refugium [1] for hunter-gatherers (HG) and thus served as a potential source for the re-peopling of northern latitudes [2]. The post-LGM genetic signature was previously described as a cline from Western HG (WHG) to Eastern HG (EHG), further shaped by later Holocene expansions from the Near East and the North Pontic steppes [3–9]. Western and central Europe were dominated by ancestry associated with the ~14,000-year-old individual from Villabruna, Italy, which had largely replaced earlier genetic ancestry, represented by 19,000-15,000-year-old individuals associated with the Magdalenian culture [2]. However, little is known about the genetic diversity in southern European refugia, the presence of distinct genetic clusters and correspondence with geography. Here, we report new genome-wide data from eleven HG and Neolithic individuals that highlight the late survival of Paleolithic ancestry in Iberia, reported previously in Magdalenian-associated individuals. We show that all Iberian HG, including the oldest ~19,000-year-old individual from El Mirón in Spain, carry dual ancestry from both Villabruna and the Magdalenian-related individuals. Thus, our results suggest an early connection between two potential refugia resulting in a genetic ancestry that survived in later Iberian HG. Our new genomic data from Iberian Early and Middle Neolithic individuals show that the dual Iberian HG genomic legacy pertains in the peninsula, suggesting that expanding farmers mixed with local HG.

欧洲西南部的伊比利亚半岛是史前时期人类人口流动研究的重要研究案例。在末次冰盛期（Last Glacial Maximum，LGM），该半岛曾为狩猎采集者（hunter-gatherers，HG）提供冰缘避难所[1]，并因此成为高纬度地区人口重新定居的潜在来源地[2]。此前，末次冰盛期后的遗传特征被描述为从西部狩猎采集者（Western HG，WHG）到东部狩猎采集者（Eastern HG，EHG）的遗传渐变群，这一特征进一步受到全新世时期来自近东与北庞蒂克草原的人群扩张的塑造[3–9]。西欧与中欧的遗传祖源主要源自意大利维拉布鲁纳遗址约14000年前的个体，该祖源基本取代了此前以马格德林文化相关的19000至15000年前个体为代表的早期遗传祖源[2]。然而，学界对南欧避难所内的遗传多样性、独特遗传簇的存在及其与地理分布的关联仍知之甚少。本研究报道了11例狩猎采集者与新石器时代个体的全新全基因组数据，揭示了伊比利亚半岛旧石器时代祖源的晚期存续现象——这一现象此前曾在马格德林文化相关个体中被报道。研究显示，所有伊比利亚狩猎采集者（包括西班牙埃尔米龙遗址约19000年前的最古老个体）均携带源自维拉布鲁纳个体与马格德林文化相关个体的双重祖源。因此，本研究结果表明，两处潜在避难所之间存在早期基因交流，由此产生的遗传祖源在后世伊比利亚狩猎采集者中得以存续。我们针对伊比利亚半岛早、中期新石器时代个体的全新基因组数据显示，伊比利亚狩猎采集者的双重祖源遗传特征仍留存于该半岛，这表明当时扩张的农耕人群与当地狩猎采集者发生了基因交流。