Unit of Human Evolutionary Genetics, Department of Genomes and Genetics, Institut Pasteur, 75015 Paris, France; Centre National de la Recherche Scientifique (CNRS), UMR2000, 75015 Paris, France; Center of Bioinformatics, Biostatistics and Integrative Biology, Institut Pasteur, 75015 Paris, France.
Curr Opin Genet Dev. 2018 Dec;53:90-97. doi: 10.1016/j.gde.2018.07.008. Epub 2018 Aug 10.
Central Africa, a forested region that supports an exceptionally high biodiversity, hosts the world's largest group of hunter-gatherers, who live in close proximity with groups that have adopted agriculture over the past 5000 years. Our understanding of the prehistory of these populations has been dramatically hampered by the almost total absence of fossil remains in this region, a limitation that has recently been circumvented by population genomics approaches. Different studies have estimated that ancestors of rainforest hunter-gatherers and Bantu-speaking farmers separated more than 60 000 years ago, supporting the occurrence of ancient population structure in Africa since the Late Pleistocene. Conversely, the Holocene in central Africa was characterized by large-scale population migrations associated with the emergence of agriculture, and increased genetic interactions between autochthonous rainforest hunter-gatherers and expanding Bantu-speaking farmers. Genomic scans have detected numerous candidate loci for positive selection in these populations, including convergent adaptation for short stature in groups of rainforest hunter-gatherers and local adaptation to endemic malaria in western and central Africans. Furthermore, there is recent increasing evidence that adaptive variation has been acquired by various African populations through admixture, suggesting a previously unappreciated role of intraspecies gene flow in local adaptation. Ancient and modern DNA studies will greatly broaden, and probably challenge, our view on the past history of central Africa, where introgression from yet uncharacterized archaic hominins and long-term adaptation to distinct ecological niches are suspected.
中非是一个森林覆盖的地区，拥有极高的生物多样性，是世界上最大的狩猎采集人群聚居地，这些人生活在与过去 5000 年来已经采用农业的人群密切相邻的地方。由于该地区几乎完全没有化石遗迹，我们对这些人群的史前史的了解受到了极大的阻碍，这一限制最近通过群体基因组学方法得到了规避。不同的研究估计，雨林狩猎采集者和班图语农民的祖先在 6 万多年前就已经分离，这支持了自更新世晚期以来非洲古代人口结构的存在。相反，中非全新世的特点是与农业出现相关的大规模人口迁移，以及当地雨林狩猎采集者和不断扩张的班图语农民之间遗传相互作用的增加。基因组扫描在这些人群中检测到了许多正选择的候选基因座，包括雨林狩猎采集者群体中身高矮小的趋同适应，以及非洲西部和中部地方性适应地方性疟疾的适应。此外，最近越来越多的证据表明，各种非洲人群通过混合获得了适应性变异，这表明种内基因流在局部适应中起到了以前未被认识到的作用。古 DNA 和现代 DNA 研究将极大地拓宽我们对中非过去历史的看法，这可能会挑战我们的看法，因为在中非，可能有尚未被描述的古老人类的基因渗入，以及对不同生态位的长期适应。
