Sickle Cell Anaemia Study Table 1 f(HnHn) f(HnSn) f(HsHs) f(Hn) f(Hs) Original geneation 7.5 2.5 0 8.0 2.0 Offspring generation 17.5 2.5 0 10 0 Summary answers on table 1. 1. The frequency of the common allele increased 2. The frequency of the rare allele decreased. 3. The frequencies were the same. 4. Allele frequency of normal haemoglobin increases as the frequency of the abnormal haemoglobin decreases.