title: Comparison of Plasmodium falciparum allelic frequency distribution in different endemic settings by high-resolution genotyping.
abstract: BACKGROUND
  The diversity of genotyping markers of Plasmodium falciparum depends on transmission intensity. It has been reported that the diversity of the merozoite surface protein 2 (msp2) is greater in areas of high compared to low endemicity, however, results for msp1 were inconsistent. These previous reports relied on low resolution genotyping techniques.
  
  
  METHODS
  In the present study, a high-resolution capillary electrophoresis-based technique was applied to genotype samples from areas of different endemicity in Papua New Guinea and Tanzania. For both endemic settings, the diversity of msp1 and msp2 was investigated; the mean multiplicity of infection (MOI) and the FST values were determined to investigate whether more accurate sizing generates different results.
  
  
  CONCLUSIONS
  The results of the present study confirmed previous reports of a higher mean MOI for both marker genes and increased genetic diversity in areas of higher endemicity as estimated by the total number of distinct alleles for msp2. For msp1 a minor increase in diversity was observed. Measures of between population variance in allele frequencies (FST) indicated little genetic differentiation for both marker genes between the two populations from different endemic settings. MOI adjusted for the probability of multiple infections sharing the same allele was estimated by using the msp2 allele frequency distribution and the distribution of observed numbers of concurrent infections. For the high-resolution typing technique applied in this study, this adjustment made little difference to the estimated mean MOI compared to the observed mean MOI.
authors.affiliation: Swiss Tropical Institute, Basel, Switzerland. s_schoepflin@hotmail.com
authors.forename: Sonja
authors.initials: S
authors.lastname: Schoepflin
authors.forename: Francesca
authors.initials: F
authors.lastname: Valsangiacomo
authors.forename: Enmoore
authors.initials: E
authors.lastname: Lin
authors.forename: Benson
authors.initials: B
authors.lastname: Kiniboro
authors.forename: Ivo
authors.initials: I
authors.lastname: Mueller
authors.forename: Ingrid
authors.initials: I
authors.lastname: Felger
mesh_terms: D000483:Alleles; D000818:Animals; D000953:Antigens, Protozoan; D019075:Electrophoresis, Capillary; D005787:Gene Frequency; D005838:Genotype; D016778:Malaria, Falciparum / Q000453:epidemiology / Q000235:genetics* / Q000635:transmission; D020066:Merozoite Surface Protein 1 / Q000235:genetics* / Q000276:immunology; D008969:Molecular Sequence Data; D010219:Papua New Guinea / Q000453:epidemiology; D010963:Plasmodium falciparum / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D015800:Protozoan Proteins; D013636:Tanzania / Q000453:epidemiology
chemical_list: D000953:Antigens, Protozoan; D020066:Merozoite Surface Protein 1; D015800:Protozoan Proteins; C065974:merozoite surface protein 2, Plasmodium