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Background: Cytochrome P450 is a superfamily of genes generating hemoproteins that metabolize foreign chemicals as well as endogenous compounds, such as steroids. The human CYP2C genes (CYP2C8, CYP2C9, CYP2C18, CYP2C19) cluster on chromosome 10 and metabolize many clinically useful drugs. CYP2C19 and CYP2C9 have been the most studied while CYP2C8 has been studied less frequently. CYP2C18 has been relatively ignored until recently but its importance has begun to be recognized., Methods and Results: We studied the genotypes of 7 pharmacogenetic markers in 3 CYP2C genes: CYP2C19 (rs12248560), CYP2C9 (rs4918758, rs1799853), and CYP2C8 (rs10509681, rs11572103, rs1058930, rs11572080), in one Libyan population and 7 Tunisian populations. Five of the 7 SNPs are in exons and have functional consequences while one intronic SNP is considered to be in close proximity to a regulatory region because of the many studies that report associations with metabolic effects. We carried out principal component analysis (PCA) on the North African populations and 83 other populations from the 1000 Genomes Project and Kidd Laboratory. The geographic clustering observed via PCA was more pronounced when considering multi-SNP haplotype frequencies., Conclusion: This study reveals the intermediate position of North Africans between Europeans and Asians and the varied dissimilarities with other world regions. The genetic variation observed within and between geographic regions have implications for drug metabolism and adverse individual responses to medical treatments., Competing Interests: Declarations Conflict of interest The authors declare no conflicts of interest. Ethical approval The Ethics Committee approved this work for Research in Life Sciences and Health of the ISBM (CER-SVS/ISBM). Informed consent Informed consent for the study and publication was obtained from all participants in this study., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

The demographic history of human populations in North Africa has been characterized by complex migration processes that have determined the current genetic structure of these populations. We examined the autosomal markers of eight sampled populations in northern Africa (Tunisia and Libya) to explore their genetic structure and to place them in a global context. We genotyped a set of 30 autosomal single-nucleotide polymorphisms (SNPs) extending 9.5 Mb and encompassing the 17q21 inversion region. Our data include 403 individuals from Tunisia and Libya. To put our populations in the global context, we analyzed our data in comparison with other populations, including those of the 1000 Genomes Project. To evaluate the data, we conducted genetic diversity, principal component, STRUCTURE, and haplotype analyses. The analysis of genetic composition revealed the genetic heterogeneity of North African populations. The principal component and STRUCTURE analyses converged and revealed the intermediate position of North Africans between Europeans and Asians. Haplotypic analysis demonstrated that the normal (H1) and inverted (H2) polymorphisms in the chromosome 17q21 region occur in North Africa at frequencies similar to those found in European and Southwest Asian populations. The results highlight the complex demographic history of North Africa, reflecting the influence of genetic flow from Europe and the Near East that dates to the prehistoric period. These gene flows added to demographic factors (inbreeding, endogamy), natural factors (topography, Sahara), and cultural factors that play a role in the emergence of the diverse and heterogeneous genetic structures of North African populations. This study contributes to a better understanding of the complex structure of North African populations., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The TAS2R38 gene is involved in bitter taste perception. This study documents the distinctive diversity patterns in northern Africa of functional single-nucleotide polymorphisms (SNPs) rs713598 and rs1726866 at the TAS2R38 locus and places those patterns in the context of global TAS2R38 diversity. Data previously genotyped with TaqMan assay were analyzed for rs713598 and rs1726866 for 375 unrelated subjects (305 Tunisians from seven locations: Mahdia, Sousse, Kesra, Nebeur, Kairouan, Smar, and Kerkennah; plus 70 Libyans). Data were analyzed to present haplotypes and genotypes before comparison with data from worldwide populations. This study provides information about TAS2R38 diversity in a part of the world that is relatively understudied. Considering the two SNPs rs713598 and rs1726866, the CA nucleotide haplotype leading to the PV amino acid haplotype is extremely rare almost everywhere, but it is relatively frequent (between 6% and 15%) in northern Africa, where it coexists with the globally common amino acid haplotypes PA, AA, and AV. Given its higher frequency in North Africa, the authors propose the CA nucleotide haplotype as a biogeographic marker for forensic purposes.

The dopamine - related genes, like dopamine D2 receptor (DRD2) gene and ankyrin repeat and kinase domain containing 1 (ANKK1) gene are implicated in neurological functions. Some polymorphisms of the DRD2/ANKK1 locus (TaqIA, TaqIB, TaqID) have been used to study genetic diversity and the evolution of human populations. The present investigation aims to assess the genetic diversity in seven North African populations in order to explore their genetic structure and to compare them to others worldwide populations studied for the same locus. Nine single nucleotide polymorphisms (SNPs) from the DRD2/ANKK1 locus (rs1800497 TaqIA, rs2242592, rs1124492, rs6277, rs6275, rs1079727, rs2002453, rs2234690 and rs1079597 TaqIB) were typed in 366 individuals from seven North African populations: six from Tunisia (Sousse, Smar, Kesra, Kairouan, Mehdia and Kerkennah) and one from Libya. The allelic frequencies of rs2002453 and rs2234690 were higher in the Smar population than in the other North African populations. More, the Smar population showed the lowest average heterozygosity (0.313). The principal component analysis (PCA) showed that the Smar population was clearly separated from others. Furthermore, linkage disequilibrium analysis shown a high linkage disequilibrium in the North African population and essentially in Smar population. Comparison with other world populations has shown that the heterozygosity of North African population was very close to that of the African and European populations. The PCA and the haplotypic analysis suggested the presence of an important Eurasian genetic component for the North African population. These results suggested that the Smar population was isolated from the others North Africans ones by its peculiar genetic structure because of isolation, endogamy and genetic drift. On the other hand, the North African population is characterized by a multi ancestral gene pool from Eurasia and sub-Saharan Africa due to human migration since prehistoric times., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The COMT gene encodes for catechol-O-methyl-transferase, an enzyme playing a major role in regulation of synaptic catecholamine neurotransmitters. Investigating 4 markers of the COMT gene (rs2020917, rs4818, rs4680, rs9332377) in 6 Tunisian populations and a pool of Libyans. Our objective was to determine the distribution of allelic, genotypic and haplotypic frequencies by comparison to other populations of the 1000 genomes project and 59 populations from the Kidd Lab dataset. The allelic frequencies established for these SNPs in the North African populations are similar to those of Europeans and South Asians. Linkage disequilibrium between these SNPs and haplotypes frequencies are different between populations whose clustering in principal components analysis (PCA) according to their geographic origin was more significant using haplotypic frequencies. COMT activity prediction by haplotypes genotyping could be limited to rs4818-rs4680 micro-haplotypes. The Low activity haplotype (CG) displays the highest frequency in African populations (55%), in the 59 Kidd Lab populations we found also that Sub-Saharan Africans, Native Americans, and some East Asian and Pacific Island populations all have frequencies in the 50-81% range for (CG) where as its lowest frequency was found in Europeans (10%), this results have been also confirmed for Southwest Asians. North Africans and South Asians with intermediate frequencies have approximately similar values (20% and 25%). Europeans show the highest frequencies of haplotypes with predicted High and Medium activity in contrast to Africans. North Africans and South Asians present similar results for all the category of the COMT activity prediction by haplotypes genotyping. The high level of genetic diversity of COMT haplotypes, not only allows distinction between populations according to their history settlement, origin and ethnicity, it constitutes a basis for studies of association of the COMT gene polymorphism with pathologies, drugs response and for forensic investigation in North African populations., (Copyright © 2019 Elsevier B.V. All rights reserved.)