Mostafa Kandil

The trans-Saharan slave trade - clues from interpolation analyses and high-resolution characterization of mitochondrial DNA lineages

BackgroundA proportion of 1/4 to 1/2 of North African female pool is made of typical sub-Saharan lineages, in higher frequencies as geographic proximity to sub-Saharan Africa increases. The Sahara was a strong geographical barrier against gene flow, at least since 5,000 years ago, when desertification affected a larger region, but the Arab trans-Saharan slave trade could have facilitate enormously this migration of lineages. Till now, the genetic consequences of these forced trans-Saharan movements of people have not been ascertained.ResultsThe distribution of the main L haplogroups in North Africa clearly reflects the known trans-Saharan slave routes: West is dominated by L1b, L2b, L2c, L2d, L3b and L3d; the Center by L3e and some L3f and L3w; the East by L0a, L3h, L3i, L3x and, in common with the Center, L3f and L3w; while, L2a is almost everywhere. Ages for the haplogroups observed in both sides of the Saharan desert testify the recent origin (holocenic) of these haplogroups in sub-Saharan Africa, claiming a recent introduction in North Africa, further strengthened by the no detection of local expansions.ConclusionsThe interpolation analyses and complete sequencing of present mtDNA sub-Saharan lineages observed in North Africa support the genetic impact of recent trans-Saharan migrations, namely the slave trade initiated by the Arab conquest of North Africa in the seventh century. Sub-Saharan people did not leave traces in the North African maternal gene pool for the time of its settlement, some 40,000 years ago.

Population relationships in the Mediterranean revealed by autosomal genetic data (Alu and Alu/STR compound systems).

The variation of 18 Alu polymorphisms and 3 linked STRs was determined in 1,831 individuals from 15 Mediterranean populations to analyze the relationships between human groups in this geographical region and provide a complementary perspective to information from studies based on uniparental markers. Patterns of population diversity revealed by the two kinds of markers examined were different from one another, likely in relation to their different mutation rates. Therefore, while the Alu biallelic variation underlies general heterogeneity throughout the whole Mediterranean region, the combined use of Alu and STR points to a considerable genetic differentiation between the two Mediterranean shores, presumably strengthened by a considerable sub-Saharan African genetic contribution in North Africa (around 13% calculated from Alu markers). Gene flow analysis confirms the permeability of the Sahara to human passage along with the existence of trans-Mediterranean interchanges. Two specific Alu/STR combinations-CD4 110(-) and DM 107(-)-detected in all North African samples, the Iberian Peninsula, Greece, Turkey, and some Mediterranean islands suggest an ancient genetic background of current Mediterranean peoples.

Genetic relationships between southeastern Spain and Morocco: New data on ABO, RH, MNSs, and DUFFY polymorphisms

The genetic polymorphism of four blood group systems (ABO, RH, MNSs, and DUFFY) was analyzed in two well‐defined population samples coming from south‐central Morocco and southeastern Spain. Both a controversial ancient common substrate and the long period of coexistence between North Africa and southern Spain during the eight centuries of the Islamic invasion of the Iberian Peninsula suggest a particular genetic relationship between northwestern Africa and southern Spain. Allele distributions in each sample are in general agreement with that expected according to the geographical and historical characteristics in the Mediterranean region. However, the differences between the Moroccan sample and other north African groups illustrate considerable genetic variability in this geographical region. In comparison with other samples from different regions of the Iberian Peninsula, the markers examined fail to demonstrate any particular affinity between the southern Spanish sample of La Alpujarra and Moroccan populations. Am. J. Hum. Biol. 11:745–752, 1999.

Usefulness of autosomal STR polymorphisms beyond forensic purposes: data on Arabic- and Berber-speaking populations from central Morocco

Background:This work describes, for the first time, the profile of Middle Atlas Berbers and Arabic-speaking central Moroccans for 15 autosomal STR loci widely used in forensic sciences. Aim: The main objectives were to determine the degree of heterogeneity among different Moroccan samples to identify geographic or linguistic patterns and to evaluate the usefulness of forensic STRs in anthropological studies. Subjects and methods: Blood samples were collected from 71 Arabic-speakers and 75 Berbers from the regions of Doukkala (central-west coast) and Khenifra (Middle Atlas), respectively. The AmpFlSTR Identifier kit was used to genotype 15 autosomal STR in both samples. Results: Middle Atlas Berbers showed slightly higher genetic variation values compared to Arabic-speakers, both in the number of alleles and heterozygosity. In order to assess population relationships, data from Morocco, Algeria, Tunisia, Libya, Egypt, Kuwait, Qatar, Palestine, Syria, South-Spain and Turkey were included in the analysis. Within Morocco, genetic distances followed a clear geographic pattern. In the Arabic-speaking sample the genetic proportion of ‘Arabian’ admixture was estimated in 13%. Conclusion: The low value of admixture suggests that the Arabization of Morocco had a reduced demographic impact, which should be taken with caution because it is based on autosomal STRs with low inter-population variation levels.

Genetic differences among North African Berber and Arab-speaking populations revealed by Y-STR diversity

Y-chromosome STR polymorphisms are inherited in a haploid state which makes them a powerful tool for easy tracing of paternal lineage and for use in human population evolutionary studies. North-African Y chromosomal diversity has traditionally been studied in order to find genetic and geographic associations as well as to test how natural and cultural barriers have affected the degree of genetic flow not only within North Africa but also in a wider Mediterranean context. The degree of Berber/Arab genetic differentiation in the Moroccan population has been tested for a complete set of forensic markers as sixteen Y-chromosomal short tandem repeats (STRs) (DYS19, DYS385, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635 and GATA H4.1). The results suggest considerable population heterogeneity in North Africa.

Digital dermatoglyphic patterns of Moroccan Arabs: relationships with mediterranean populations

Dermatoglyphic finger patterns and pattern intensity were examined in a sample of 204 (105 males and 99 females) adults from the authochthonous Arab population of south central Morocco. No significant sex differences were found for the overall finger pattern incidence or for the pattern intensity index. A high incidence of arches is the most remarkable characteristic of this population as compared to other Mediterranean groups. The significant differences from two previous sets of Moroccan data indicate a remarkable heterogeneity within the present day Moroccan population. Also important is the differentiation of this sample from other north African ethnic groups such as Berbers and Tuaregs. An analysis of the dermatoglyphic relationships using R-matrix analysis, shows a relative proximity between this Moroccan series and other southwest European groups as compared to north African populations.

Variability of candidate genes for cardiovascular risk in the Mediterranean

A screening of 22 DNA polymorphisms has been performed in western Mediterranean populations. The analyzed markers correspond to polymorphic sites in several candidate genes for cardiovascular disease including apolipoproteins and their receptor, genes implied in the hemostasis regulation and the angiotensin converting enzyme gene. The results showed a significant degree of interpopulation diversity, in agreement with previous data from other polymorphisms. The genetic distance pattern is compatible with a south-to-north African influence in the Iberia Peninsula and a remarkable gene flow sub-Saharan Africa into Morocco.