Evolutionary race: Malaria evolves to evade sickle cell protection.

Sickle cell haemoglobin (HbS) confers protection, albeit incomplete, from severe malaria. A recent study by Band et al. in Nature on parasite genomic variation of severe malaria cases identifies parasite genomic regions with alleles associated with severe disease risk in HbS individuals. The protective effect of HbS depends therefore on parasite genotype.