SEROLOGICAL ANALYSIS OF THE ABBAD TRIBE OF JORDAN

The Abbad are one of the largest tribes in Jordan with a complex struc ture dictated by historical and cultural factors, To study the genetic variability within the tribe, we examined four samples representing d ifferent levels of tribal structure for the polymorphisms of five bloo d groups, five erythrocyte enzymes, and seven serum proteins. The obta ined allele distributions indicate a wide range of genetic variability within the tribe, An allelic heterogeneity test revealed significant differences between the examined samples, yet a gene diversity analysi s revealed no significant substructuring. The observed genetic relatio nships among the four samples appear to agree with the tribal organiza tion. Endogamous mating within the tribe and inbreeding within the sub units are believed to be the main factors that influenced the observed variability. This was confirmed by the results of the R matrix analys is, which summarized the genetic relationships in concordance with int ertribal admixture, when affiliation and historical and maternal links were considered. The study is also an example of gene diffusion and o f a negative relationship between the FY A-B- phenotype and endemicity of malaria.