Population genetics of abnormal haemoglobins in Burkina Faso, west Africa.

The gene frequencies of haemoglobin A (HbA), HbS and HbC were studied in Burkina-Faso (BF) and in a neighbouring region of Niger, Ayorou. The frequency of HbS was higher in the Sahel region, (northern part of BF and Ayorou) than in the Savanna region. The reverse was true for the HbC gene. The major findings of this study are: (a) confirmation of a peak of HbC gene frequency in the central region of BF (Mossi plateau); (b) a possible negative correlation between the frequencies of HbS and HbC-Cavalli-Sforza and Bodmer have observed that this correlation is at a significantly different level from that expected because of the allelic relationship between HbS and HbC; (c) comparison with the data collected by Livingstone shows a modification in the fitness of the different genotypes in the last thirty years: AS individuals have a lower and AA and SS a higher fitness. Our data favour a partial selection relaxation in this region.