The transatlantic slave trade was the largest forced migration in world history. However, the origins of the enslaved Africans and their admixture dynamics remain unclear. To investigate the demographic history of African-descendant Marron populations, we generated genome-wide data (4.3 million markers) from 107 individuals from three African-descendant populations in South America, as well as 124 individuals from six west African populations. Throughout the Americas, thousands of enslaved Africans managed to escape captivity and establish lasting communities, such as the Noir Marron. We find that this population has the highest proportion of African ancestry (∼98%) of any African-descendant population analyzed to date, presumably because of centuries of genetic isolation. By contrast, African-descendant populations in Brazil and Colombia harbor substantially more European and Native American ancestry as a result of their complex admixture histories. Using ancestry tract-length analysis, we detect different dates for the European admixture events in the African-Colombian (1749 CE; confidence interval [CI]: 1737–1764) and African-Brazilian (1796 CE; CI: 1789–1804) populations in our dataset, consistent with the historically attested earlier influx of Africans into Colombia. Furthermore, we find evidence for sex-specific admixture patterns, resulting from predominantly European paternal gene flow. Finally, we detect strong genetic links between the African-descendant populations and specific source populations in Africa on the basis of haplotype sharing patterns. Although the Noir Marron and African-Colombians show stronger affinities with African populations from the Bight of Benin and the Gold Coast, the African-Brazilian population from Rio de Janeiro has greater genetic affinity with Bantu-speaking populations from the Bight of Biafra and west central Africa.

中文翻译：

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来自法属圭亚那和苏里南的非洲后裔栗色社区的全基因组祖先和人口历史。

跨大西洋奴隶贸易是世界历史上最大的强迫移民。但是，被奴役的非洲人的起源及其混合动力仍然不清楚。为了调查非洲后裔马龙种群的人口历史，我们从南美的三个非洲后裔种群的107个个体以及六个西非种群的124个个体生成了全基因组数据（430万个标记）。在整个美洲，成千上万被奴役的非洲人逃脱了囚禁，建立了持久的社区，例如黑马伦。我们发现，到目前为止，在所有非洲后裔人口中，这一人口的非洲血统比例最高（约98％），这可能是由于几个世纪以来的遗传隔离所致。相比之下，巴西和哥伦比亚的非洲后裔人口由于其复杂的混合历史而拥有更多的欧洲和美洲原住民血统。使用祖先长度分析，我们检测到非洲裔哥伦比亚人（1749年；可信区间[CI]：1737–1764年）和非洲裔巴西人（1796年； CI：1789年至1804年）人群中欧洲混合事件的不同日期在我们的数据集中，与历史上证实的非洲人早期涌入哥伦比亚的情况一致。此外，我们发现了主要来自欧洲父系基因流的性别特异性混合模式的证据。最后，我们根据单倍型共享模式发现了非洲后裔种群与非洲特定来源种群之间的紧密遗传联系。