title: Origins of sequence diversity in the malaria vaccine candidate merozoite surface protein-2 (MSP-2) in Amazonian isolates of Plasmodium falciparum.
abstract: The recent evolution of Plasmodium falciparum is at odds with the extensive polymorphism found in most genes coding for antigens. Here, we examined the patterns and putative mechanisms of sequence diversification in the merozoite surface protein-2 (MSP-2), a major malarial repetitive surface antigen. We compared the msp-2 gene sequences from closely related clones derived from sympatric parasite isolates from Brazilian Amazonia and used microsatellite typing to examine, in these same clones, the haplotype background of chromosome 2, where msp-2 is located. We found examples of msp-2 sequence rearrangements putatively created by nonreciprocal recombinational events, such as replication slippage and gene conversion, while maintaining the chromosome haplotype. We conclude that these nonreciprocal recombination events may represent a major source of antigenic diversity in MSP-2 in P. falciparum populations with low rates of classical meiotic recombination.
authors.affiliation: Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 1374, 05508-900 São Paulo (SP), Brazil.
authors.forename: Erika H E
authors.initials: EH
authors.lastname: Hoffmann
authors.forename: Rosely S
authors.initials: RS
authors.lastname: Malafronte
authors.forename: Sandra L
authors.initials: SL
authors.lastname: Moraes-Avila
authors.forename: Ana Lúcia
authors.initials: AL
authors.lastname: Osakabe
authors.forename: Gerhard
authors.initials: G
authors.lastname: Wunderlich
authors.forename: Alan M
authors.initials: AM
authors.lastname: Durham
authors.forename: Paulo Eduardo M
authors.initials: PE
authors.lastname: Ribolla
authors.forename: Hernando A
authors.initials: HA
authors.lastname: del Portillo
authors.forename: Marcelo U
authors.initials: MU
authors.lastname: Ferreira
mesh_terms: D000483:Alleles; D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics* / Q000276:immunology; D001483:Base Sequence; D001938:Brazil; D002874:Chromosome Mapping; D002875:Chromosomes; D003198:Computer Simulation; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics*; D019143:Evolution, Molecular; D005785:Gene Conversion; D017344:Genes, Insect; D005819:Genetic Markers; D006239:Haplotypes; D015810:Linkage Disequilibrium; D017780:Malaria Vaccines; D008390:Markov Chains; D018895:Microsatellite Repeats; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification*; D015800:Protozoan Proteins / Q000235:genetics* / Q000276:immunology; D017422:Sequence Analysis, DNA
chemical_list: D000953:Antigens, Protozoan; D016054:DNA, Protozoan; D005819:Genetic Markers; D017780:Malaria Vaccines; D015800:Protozoan Proteins; C065974:merozoite surface protein 2, Plasmodium