title: Allelic dimorphism-associated restriction of recombination in Plasmodium falciparum msp1.
abstract: Allelic dimorphism is a characteristic feature of the Plasmodium falciparum msp1 gene encoding the merozoite surface protein 1, a strong malaria vaccine candidate. Meiotic recombination is a major mechanism for the generation of msp1 allelic diversity. Potential recombination sites have previously been mapped to specific regions within msp1 (a 5' 1-kb region and a 3' 0.4-kb region) with no evidence for recombination events in a central 3.5-kb region. However, evidence for the lack of recombination events is circumstantial and inconclusive because the number of msp1 sequences analysed is limited, and the frequency of recombination events has not been addressed previously in a high transmission area, where the frequency of meiotic recombination is expected to be high. In the present study, we have mapped potential allelic recombination sites in 34 full-length msp1 sequences, including 24 new sequences, from various geographic origins. We also investigated recombination events in blocks 6 to 16 by population genetic analysis of P. falciparum populations in Tanzania, where malaria transmission is intense. The results clearly provide no evidence of recombination events occurring between the two major msp1 allelic types, K1-type and Mad20-type, in the central region, but do show recombination events occurring throughout the entire gene within sequences of the Mad20-type. Thus, the present study indicates that allelic dimorphism of msp1 greatly affects inter-allelic recombination events, highlighting a unique feature of allelic diversity of P. falciparum msp1.
authors.affiliation: Laboratory of Malariology, International Research Center of Infectious Diseases, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan. kztanabe@biken.osaka-u.ac.jp
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Tanabe
authors.forename: Naoko
authors.initials: N
authors.lastname: Sakihama
authors.forename: David
authors.initials: D
authors.lastname: Walliker
authors.forename: Hamza
authors.initials: H
authors.lastname: Babiker
authors.forename: Abdel-Muhsin A
authors.initials: AM
authors.lastname: Abdel-Muhsin
authors.forename: Bernard
authors.initials: B
authors.lastname: Bakote'e
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohmae
authors.forename: Nobuko
authors.initials: N
authors.lastname: Arisue
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Horii
authors.forename: Ingegerd
authors.initials: I
authors.lastname: Rooth
authors.forename: Anna
authors.initials: A
authors.lastname: Färnert
authors.forename: Anders
authors.initials: A
authors.lastname: Björkman
authors.forename: Lisa
authors.initials: L
authors.lastname: Ranford-Cartwright
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D002648:Child; D002675:Child, Preschool; D002874:Chromosome Mapping; D017125:Genes, Protozoan; D014644:Genetic Variation; D005828:Genetics, Population; D006239:Haplotypes; D006801:Humans; D007223:Infant; D016778:Malaria, Falciparum / Q000469:parasitology / Q000635:transmission; D020066:Merozoite Surface Protein 1 / Q000235:genetics*; D008875:Middle Aged; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000235:genetics* / Q000302:isolation & purification; D011995:Recombination, Genetic; D017386:Sequence Homology, Amino Acid; D013636:Tanzania
chemical_list: D020066:Merozoite Surface Protein 1