(3) International Reference Centre (WHO) for human immunoglobulin genetic markers. Centre Régional de Transfusion Sanguine, B.P.5, 76230-Bois-

The results of a population genetic investigation on Lebanese are given and compared with the results obtained on other populations from near and Middle-East. 2005 unrelated male and female individuals of different ages were tested for the allotypes G1m(1, 2 et 3) and G3m(5,10,11,13,14 and 21); a smaller number of them was also tested for G1m(17), G2m(23) and G3m(6). The allotype ISf(1) on 380. The Lebanese population presents with a great frequency the four Gm haplotypes most commonly found in a Caucasoid population, Gm3;23;5,10,11,13,14 (.5568), Gm1,17;..;21 (.1726), Gm3;..;5,10,11,13,14 (.1661) and Gm1,2,17;..;21 (.0224), which can explain 85,64 % of the observed phenotypes. The Km1,2 allele frequency (.072) as well as the variations of the frequency of ISf(1) phenotype according to the age, are also characteristic of This work was partly supported by the "Conseil National de la Recherche Scientifique Libanaise", by the "Fondation pour la Recherche Médicale Française " an