Institut de Biologia Evolutiva (UPF-CSIC), Departament de Medicina i Ciències de la Vida, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona, 08003, Barcelona, Spain.
Centro de Investigación Biomédica en Red de Salud Mental, Instituto de Salud Carlos III, 28029, Madrid, Spain.
Sci Rep. 2023 May 20;13(1):8166. doi: 10.1038/s41598-023-35312-3.
Because of its location, North Africa (NA) has witnessed continuous demographic movements with an impact on the genomes of present-day human populations. Genomic data describe a complex scenario with varying proportions of at least four main ancestry components: Maghrebi, Middle Eastern-, European-, and West-and-East-African-like. However, the footprint of positive selection in NA has not been studied. Here, we compile genome-wide genotyping data from 190 North Africans and individuals from surrounding populations, investigate for signatures of positive selection using allele frequencies and linkage disequilibrium-based methods and infer ancestry proportions to discern adaptive admixture from post-admixture selection events. Our results show private candidate genes for selection in NA involved in insulin processing (KIF5A), immune function (KIF5A, IL1RN, TLR3), and haemoglobin phenotypes (BCL11A). We also detect signatures of positive selection related to skin pigmentation (SLC24A5, KITLG), and immunity function (IL1R1, CD44, JAK1) shared with European populations and candidate genes associated with haemoglobin phenotypes (HPSE2, HBE1, HBG2), other immune-related (DOCK2) traits, and insulin processing (GLIS3) traits shared with West and East African populations. Finally, the SLC8A1 gene, which codifies for a sodium-calcium exchanger, was the only candidate identified under post-admixture selection in Western NA.
由于其地理位置，北非（NA）见证了持续的人口迁移，这对当今人类群体的基因组产生了影响。基因组数据描述了一个复杂的情景，其中至少有四个主要祖先成分的比例不同：马格里布、中东部、欧洲和西部和东部非洲。然而，NA 中的正选择足迹尚未得到研究。在这里，我们编译了来自 190 名北非人和周围人群的全基因组基因分型数据，使用等位基因频率和连锁不平衡基于方法调查正选择的特征，并推断祖先比例，以区分适应性混合和混合后选择事件。我们的研究结果表明，在 NA 中，涉及胰岛素加工的基因（KIF5A）、免疫功能（KIF5A、IL1RN、TLR3）和血红蛋白表型（BCL11A）存在选择的私有候选基因。我们还检测到与欧洲人群共享的与皮肤色素沉着（SLC24A5、KITLG）和免疫功能（IL1R1、CD44、JAK1）相关的正选择信号，以及与血红蛋白表型（HPSE2、HBE1、HBG2）、其他免疫相关（DOCK2）特征和胰岛素加工（GLIS3）特征相关的候选基因，与西非和东非人群共享。最后，编码钠钙交换器的 SLC8A1 基因是在 NA 西部混合后选择下唯一确定的候选基因。
