HB O-ARAB [BETA-121(GH4)GLU-]LYS] - ASSOCIATION WITH DNA POLYMORPHISMS OF AFRICAN ANCESTRY IN 2 MEDITERRANEAN FAMILIES

Hb O-Arab [beta121(GH4)Glu->Lys] was detected in two Mediterranean fam ilies, one from Southern Italy and the other from Albania. The GAA und erbar->AAA underbar mutation at codon 121 was characterized by DNA seq uencing. The mutant genes were associated with the same beta-globin ge ne framework variant and with the rare Hpa I/3'beta polymorphic restri ction site generating a 7.0 kb fragment. However, at 5' the gene of th e Italian family was associated with the restriction fragment length p olymorphism subhaplotype [+ - - - +] and the Taq I/3'(G)gamma polymorp hic site, while that of the Albanian family was associated with subhap lotype [- - - - +] but not with the Taq I/3'(G)gamma site. The particu lar features of these polymorphisms support the hypothesis of an Afric an origin for the Hb O-Arab gene and a subsequent recombination event leading to the haplotype found in the Italian family.