Question

What do the results in Table 22.4 suggest about sickle-cell hemoglobin and malaria? A hemoglobin genotype in children normal (homozygous normal) mild sickling (heterozygous) B hemoglobin genotype in adult males normal (homozygous normal) mild sickling (heterozygous) percent with malaria parasite present 45.7 27.9 percent with malaria parasite present 93.3 percent with high parasite density 66.0 33.3 percent with high parasite density 40.0 0 13.3 Table 22.4. Incidence of the malaria parasite in blood of normal and sickle-cell children from a small community in Uganda, Africa, and adult males dosed with the malaria parasite Normal individuals have a selective advantage in regions where malaria is not present. Homozygous individuals with sickle-cell disease died before the results were in. Heterozygous individuals have a selective advantage in regions where malaria is prevalent. Heterozygous individuals tend to have much lower infection rates than normal homozygous individuals.

Answer 1

If you see the table 22.4, none of the values are matching to the statement except last one wherein homozygous condition showing severity as compared to the heterozygous one. Therefore, correct option would be 'Heterozygous individuals tend to have much lower infection rates than normal homozygous individuals’.

After scrutinising the table 22.5, you can Osp-C negative that means bacteria without gene encoded for Osp-C is not showing any infection like no antibody formation or presence of pathogenic bacteria in the tissue of mouse and no tick infection as well. Hence, answer is 'Bacteria without the OSP-C gene can successfully avoid infection'. Remaining all other options are not following the trend as given in the table.