1. In human populations in Africa, two common alleles affect the structure of hemoglobin, the protein that carries oxygen on red blood cells. What is regarded as the normal allele(the allele common in European populations) is usually labeledA, and the sickle-cell alleleis designatedS. There are three hemoglobin genotypes, and the phenotypes associated withthese genotypes can be distinguished in a variety of ways. In one African population of10,000 adults, for example, there are 4,000ASindividuals, 6,000AAindividuals, and 0SSindividuals.