STR-based genetic structure of the Berber population of Bejaia (Northern Algeria) and its relationships to various ethnic groups

Genetic analysis based on 15 autosomal short tandem repeats (STRs) in the Chaouia population, western center Morocco, and genetic relationships with worldwide populations

The complex demographic history of human populations in North Africa has resulted in a high degree of genetic heterogeneity across the region. However, little is known about the pattern of these genetic variations in its current populations. The present study provides new data on the genetic background of Chaouia, an Arabic-speaking North African population in the western center of Morocco. A random sample of 150 unrelated healthy individuals from Chaouia was assessed using the AmpFLSTR Identifiler kit. The most polymorphic markers were D21S11 and D18S51, with 23 and 22 alleles, respectively. After Bonferroni's correction, two loci (TH01 and D18S51) deviated from Hardy-Weinberg equilibrium. The phylogeny analysis separated North African populations into northeastern and northwestern groups. The Chaouia population was clustered with northwestern Africans. It was the closest to the Berbers of Azrou. The Chaouia shared close genetic affinities with populations from North Africa, the Middle East, and Europe, particularly Iberians, and to a lesser extent with sub-Saharan populations. The pattern of genetic admixture varied across North African populations without a clear correlation between their geographic (northeastern or northwestern) or linguistic identities (Arab or Berber), however, genetic heterogeneity among Berbers was observed. These findings suggest that the diversity observed in North African populations extends geographical and linguistic boundaries. It is further linked to each population's unique and complex demographic history. Human North African population genetics seems to present an intriguing landscape for future studies in the region and its surrounding populations to trace the origins of the genetic heterogeneity observed in these populations.

Genetic characterization of the Berber-speaking population of Souss (Morocco) based on autosomal STRs

BACKGROUND

The Souss, located in southern Morocco, is one of the oldest areas of human settlement in North Africa. Despite this historical relevance, the Souss has not received sufficient attention in terms of population genetic studies.

METHODS

In this study, we utilized the AmpFlSTR Identifiler PCR amplification system to establish the allelic frequencies and statistical parameters of 15 autosomal STRs (Short Tandem Repeats) in 150 healthy unrelated Berber-speaking individuals from the Souss. We explored the genetic relationships between Souss and other reference populations based on our dataset as well as previously published population data.

RESULTS

A total of 210 alleles were detected with corresponding allele frequencies ranging from 0.003 to 0.367. The most polymorphic locus was D18S51 with 23 alleles which was also the most discriminating locus as expected. The phylogenetic analysis clustered the Souss closer to the Azrou and southern Moroccan populations. The population comparison showed affinity between the Souss and most North African populations, as well as with Middle Easterners and Europeans.

CONCLUSION

Historical events and geographical proximity have contributed to the affinity between the Souss and surrounding North African, Southern European, and Middle Eastern populations. Overall, this study highlights the reliability of the 15 STRs for identifying individuals and assessing paternity in the Souss population.

Insights into the Middle Eastern paternal genetic pool in Tunisia: high prevalence of T-M70 haplogroup in an Arab population

To obtain refreshed insights into the paternal lineages of Tunisian populations, Y-chromosome diversity was assessed in two populations belonging to an Arab genealogical lineage, Kairouan and Wesletia, as well as in four Tunisian Andalusian populations, Testour, Slouguia, Qalaat-El-Andalous and El Alia. The Arabs from Kairouan revealed 73.47% of E-M81 and close affinities with Berber groups, indicating they are likely arabized Berbers, clearly differentiated from the Arabs from Wesletia, who harbored the highest frequency (71.8%) of the Middle Eastern component ever observed in North Africa. In the Tunisian Andalusians, the North African component largely prevailed, followed by the Middle Eastern contribution. Global comparative analysis highlighted the heterogeneity of Tunisian populations, among which, as a whole, dominated a set of lineages ascribed to be of autochthonous Berber origin (71.67%), beside a component of essentially Middle Eastern extraction (18.35%), and signatures of Sub-Saharan (5.2%), European (3.45%) and Asiatic (1.33%) contributions. The remarkable frequency of T-M70 in Wesletia (17.4%) prompted to refine its phylogeographic analysis, allowing to confirm its Middle Eastern origin, though signs of local evolution in Northern Africa were also detected. Evidence was clear on the ancient introduction of T lineages into the region, probably since Neolithic times associated to spread of agriculture.

Genetic diversity of 15 autosomal STRs in a sample of Berbers from Aurès region in the Northeast of Algeria and genetic relationships with other neighbouring samples

Background: The history of the Aurès mountains and neighbouring areas, a large region of the East of Algeria, was part of the history of the ancient independent Berber kingdoms supposed to be the ancestors of the current Berber people. The genetic background of this region has not yet been clarified.Aim: The aims of our study were to investigate the genetic characteristics of 15 autosomal short tandem repeats (STRs) in a sample from these regions, to determine the degree of heterogeneity among Algerian and North African samples and to analyse the genetic relationships with other populations.Subjects and methods: Allele frequencies, forensic parameters and Hardy-Weinberg equilibrium (HWE) of 15 autosomal STRs included in the PowerPlex^® ESI 16 System were obtained from 308 individuals. Allele frequencies were used to determine the relationships with other populations.Results: All loci were highly polymorphic and no significant deviation from HWE was detected. Allele frequencies showed that the samples of Aurès region share genetic affinities with other Algerian, North African and Middle Eastern samples, with the exception of samples from Iran and Matmata.Conclusions: These markers revealed a genetic homogeneity between the Algerian and North African samples. The genetic affinities indicate that this sample could share a common ancestor with the Middle Eastern samples.

Paternal lineage of the Berbers from Aurès in Algeria: estimate of their genetic variation

Background: Aurès is a vast territory in the east of Algeria, characterised by its traditional Berber settlement which has preserved its language and its rich history; its name goes back to antiquity and before the Roman conquest it was part of the territory of ancient Numidia. The Chaoui people in this region are one of Algeria's largest Berber groups. Aim: The aims were to investigate the level of genetic diversity of the Berbers of Aurès through the analysis of the paternal gene pool and to estimate the percentage of genetic variation among different geographical regions and linguistic groups from Algeria. Subjects and methods: Twenty-three Y-STRs were genotyped in a sample of 218 unrelated males of the Berbers of Aurès. Algorithms were used to estimate the Y-chromosome haplogroups. Genetic distance, non-metric MDS and AMOVA were used to analyse the genetic relationships between sample groups. Results: The paternal lineage of this sample of the Aurès region did not exhibit strong signals of differentiation with other samples from North-central, Northwest, and South Algeria. However, significant differences were found within this sample, demonstrating a high degree of heterogeneity. Conclusion: The results demonstrate that Aurès people are isolated and closed, but nevertheless have quite different genetic profiles.

Genetic polymorphisms and periodontal disease in populations of African descent: A review

Aggressive periodontitis is a rare but rapidly progressing form of periodontal disease that usually affects otherwise systemically healthy individuals, at a young age. It usually affects first molars and incisors, which are usually lost if treatment is not properly and early rendered. Although of low prevalence, it affects individuals of African descent at a higher prevalence, and usually multiple members within the same family. Several studies have been performed in the attempt to evaluate specific single nucleotide polymorphisms (SNPs) that could be associated with this disease. To the best of our knowledge, the present article provides the first review of the literature focusing on studies that evaluated SNPs in patients of African descent with aggressive periodontitis. Several SNPs have been evaluated in different genes according to their role in the pathogenesis of the disease, with positive and negative associations (such as IL1, FCGR3B, FPR1, LTF, CYBA, GLT6D1, TLR4) with both the localized and generalized forms of aggressive periodontitis. Given the complexity of periodontitis, the difficulty in gathering large cohorts diagnosed with this rare form of disease, and the fact that candidate gene studies may only determine part of the genetic risk of a disease, the search for specific SNPs associated with aggressive periodontitis seems to be a long one, most likely to result in the combination of multiple SNPs, in multiple genes.