查看文章

New strategies are required to identify the most important targets of protective immunity in complex eukaryotic pathogens. Natural selection maintains allelic variation in some antigens of the malaria parasite Plasmodium falciparum 1, 2, 3. Analysis of allele frequency distributions could identify the loci under most intense selection 4, 5, 6, 7. The merozoite surface protein 1 (Msp1) is the most-abundant surface component on the erythrocyte-invading stage of P. falciparum 8, 9, 10. Immunization with whole Msp1 has protected monkeys completely against homologous 11 and partially against non-homologous 12 parasite strains. The single-copy msp1 gene, of about 5 kilobases, has highly divergent alleles 13 with stable frequencies in endemic populations 14, 15. To identify the region of msp1 under strongest selection to maintain alleles within populations, we studied multiple intragenic sequence loci in populations in …