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.