Northwest African distribution of the CD4/Alu microsatellite haplotypes

We have analysed a linked microsatellite/Alu polymorphism at the CD4 locus (CD4/Alu) in 666 chromosomes from samples of the Iberian Peninsula, Northwe st Africa, and West sub-Saharan Africa. The Iberian Peninsula differs from other European populations by its higher levels of haplotype diversity (0.7 5), and weaker association Between the microsatellite allele 90 and Alu(-) chromosomes. These results are explainable by a substantial gene flow from Northwest Africa. Significant geographic dines for the five major haplotype s suggest a south to north migration from sub-Saharan Africa into Northwest Africa. In spite of this, the consistent presence of haplotype 110(-) in t his area is congruent with an ancient and autochthonous human presence in N orthwest Africa.