Study of GM immunoglobulin allotypic system in Berbers and Arabs from Morocco.

The GM immunoglobulin allotype polymorphism was investigated in four Moroccan populations: three Berber groups from Khenifra (Middle Atlas), Amizmiz (High Atlas), and Bouhria (Beni Snassen) and one Arabic-speaking sample from the Doukkala area (Abda, Chaouia, Doukkali, and Tadla districts in south-central Morocco). In order to characterize the genetic relationships between the populations, our results were compared with those obtained for other North African groups (from Morocco, Algeria, Tunisia, and Niger) and for Middle-East Africans, sub-Saharans, and Southwest Europeans. Based on GM haplotype frequencies, Factorial Correspondence Analyses, F(ST) significance testing, and hierarchical analyses of variance were performed. Our results reveal that Moroccan populations have heterogeneous GM profiles with high frequencies of GM haplotypes in Europeans (from 76% for Doukkala to 88% for Bouhria) and relatively high frequencies of GM haplotypes in sub-Saharans (from 11% for Bouhria to 23% for Amizmiz). The genetic diversity observed among Moroccans is not significantly correlated with either geographic or linguistic differentiation. In spite of their cultural and historical differentiation, we did not discover any significant genetic differences between Berbers and Arabic-speakers from Morocco. However, when large geographical areas are considered, our population samples are integrated in the North African GM variation, significantly distant from sub-Saharan groups but with a close relationship with Southwest European populations.

An unexpected wide population variation of the G1733A polymorphism of the androgen receptor gene: data on the Mediterranean region.

The androgen receptor (AR) has been proposed as a candidate gene for several cancers (breast, prostate, uterine endometrium, colon, and esophagus). Ethnicity is considered an associated risk factor for some of these cancers. Several case-control genetic studies have been focused in samples of the main ethnic groups, but little is known about the distribution of risk polymorphisms in current populations with accurate ethnic and/or geographic origins. The A allele of the G1733A polymorphism of the AR gene has been associated with increased risk of prostate cancer. We provide data from this marker in 12 samples from 7 Mediterranean countries such as Spain, Italy (Sardinia), Greece, Turkey, Morocco, Algeria, and Egypt. A sample from Ivory Coast has also been analyzed. The A allele distribution shows a frequency in the Ivory Coast population (65.17%) that contrasts with the low values found in Northern Mediterraneans (mean average value of 13.98%). North African populations present two-times higher frequencies (average value of 27.19%) than Europeans. The wide population variation range found for the A allele strengthens the potential interest of further screening as a baseline to the design of future preventive and population health programs.

Genetic relationships among Berbers and South Spaniards based on CD4 microsatellite/Alu haplotypes.

BACKGROUND: CD4 STR/Alu haplotype diversity, both for its qualitative and quantitative properties, has been widely used in molecular anthropology to clarify the degree of genetic relationships among human populations. AIM: CD4 STR/Alu variation was studied in two West Mediterranean samples, Andalusians from La Alpujarra region on the north side of the Gibraltar Strait and Berbers from the south, to ascertain the pattern of affinities between them. SUBJECTS AND METHODS: Alu and microsatellite alleles were tested in 99 Andalusians from La Alpujarra region (Southeast Spain) and 124 Middle Atlas Berbers (Morocco). RESULTS: Two new combinations of Alu and STR alleles (75(+) and 80(-)) were found in Berbers. The CD4 STR/Alu haplotype distribution in South Spaniards is similar to that of other Europeans, the only special feature is the slight presence of the 90(+) and 130(+) typical Sub-Saharan haplotypes. The Berber sample is characterized by a high number of different haplotypes (18) with intermediate heterozygosity values (0.846) in comparison with other North African groups, and by a high frequency of the 110(-) combination that has been proposed as representative of an ancient Northwest African population. CONCLUSION: A geographical gradient of Sub-Saharan gene contribution has been detected in North Africa. The Middle Atlas Berbers showed an intermediate value in comparison with the high and low values found in Mauritanians and Moroccan Berbers, respectively. The analysis of the CD4 STR/Alu haplotype variation failed to indicate any particular relationship between South Spaniards and North Africans.

Classical polymorphisms in Berbers from Moyen Atlas (Morocco): genetics, geography, and historical evidence in the Mediterranean peoples.

BACKGROUND: Mediterranean population relationships have recently been reviewed through the analysis of classical and DNA markers. The differentiation between Berbers and Arabic-speakers to the south, and the genetic impact of the seven centuries of Muslim domination in the Iberian Peninsula have been among the most interesting questions posed in these studies. AIM: The present study seeks to assess the degree of genetic affinity between the two main population groups of Morocco: Berbers and Arabic-speakers. Data from the Berber study population were also compared with published information on 20 circum-Mediterranean groups. SUBJECTS AND METHODS: A Berber sample of 140 individuals from Moyen Atlas (Morocco) has been characterized using 15 classical markers (ABO, Duffy, MNSs, Rh, ACPl, AKl, ESD, GLOI, 6-PGD, PGMl, GC, HP, PI, PLG and TF). RESULTS: Allele frequencies in the Berbers fit well into the general southern Mediterranean ranges, albeit with some peculiarities, such as the high FY*A, ACPl*C, and PI*S values. The general pattern of relationships among Mediterranean peoples tested by genetic variance analysis was compatible with a north-south geographical differentiation. Spatial auto-correlation analysis in the different geographical regions of the Mediterranean reveals that the highest degree of association between allele frequencies and geographical distances corresponds to the western (41% of significant correlograms) and northern Mediterranean populations (33%). When only southern Mediterranean groups were considered, the degree of geographical structure considerably decreases (11% of significant correlograms). CONCLUSIONS: The different loci studied revealed close similarity between the Berbers and other north African groups, mainly with Moroccan Arabic-speakers, which is in accord with the hypothesis that the current Moroccan population has a strong Berber background. Differences in the spatial pattern of allele frequencies also are compatible with specific population histories in distinct Mediterranean areas, rather than general population movements across the whole region.

Apolipoprotein molecular variation in Moroccan Berbers: pentanucleotide (TTTTA)n repeat in the LPA gene and APOE-C1-C2 gene cluster.

Apolipoprotein LPA, APOE, APOC1, and APOC2 genotype frequencies have been determined for the first time in a North African population. A sample of 140 Berber individuals from the Moroccan Moyen Atlas region has been analyzed. Allelic and haplotypic data have been used to compare our sample with other world populations and the results clearly differentiate Berbers from Europeans and Sub-Saharans, suggesting several distinctive features of Moroccan Berbers as the extreme high values of LPA PNR*11 pentanucleotide allele (10.5%) and the relatively high and low values of APOE*E4 (15.7%) and *E2 (4.5%) in comparison to other Mediterraneans. Another remarkable result is the frequency distribution of the two APOC2 alleles (70% vs 30%) in comparison with the European pattern (50% of each allele). The high values of APOE*E4 and LPA PNR*7 together with the intermediate linkage disequilibrium values between APOE and APOC1 alleles in comparison with Europeans and Africans suggest a certain degree of Sub-Saharan influence in the current Moroccan population.

Dermatoglyphic characterization of Berbers from Morocco: qualitative and quantitative digital and palm data.

BACKGROUND: The demographic impact of the Arabization in the Berber genetic background has been extensively studied by means of different classical and DNA genetic markers. Information from other biological traits as dermatoglyphics could be of interest in order to gain an insight into the relationship between these two North African groups. AIM: The Moroccan Berber population is characterized by means of digital and palm dermatoglyphics to determine the degree of genetic affinities among Berber and other Mediterraneans, especially the Moroccan Arab-speakers. SUBJECTS AND METHODS: Finger patterns, pattern intensity, finger total ridge counts, pattern frequencies in the five configuration areas of the palm, mainline D terminations, and a-b ridge count were analysed in a sample of 120 males and 103 females of Moyen Atlas (Morocco). RESULTS: Bilateral asymmetry was more pronounced than sexual differences in the overall distribution of the analysed traits. Our two series (males and females) exhibit high values of total ridge count (TRC) and mainline D terminations in comparison with other Mediterranean series. Several pattern frequencies in fingers and palm areas also differentiate the Berbers of Moyen Atlas from North Africans. CONCLUSION: The picture obtained by principal components based on qualitative digital and palm data revealed that Berber males were within the variation range of North African groups while Berber females clustered with some Iberian samples. The population pattern obtained in a bivariate plot of quantitative finger data showed the Berbers (males and females) as the most differentiated population in the Mediterranean context. Dermatoglyphic data failed to indicate any particular proximity between Berbers and Arab-speakers from Morocco.