title: Positive selection and interallelic recombination at the merozoite surface antigen-1 (MSA-1) locus of Plasmodium falciparum.
abstract: DNA sequences of alleles at the merozoite surface antigen-1 (MSA-1) gene locus of the malaria parasite Plasmodium falciparum show evidence of repeated past recombination events between alleles. These include both (1) nonreciprocal recombination events that have homogenized certain gene regions among alleles and (2) reciprocal recombination events that have combined allelic segments with divergent evolutionary histories, thereby enhancing allelic diversity. In three different gene regions, the rate of nonsynonymous nucleotide substitution significantly exceeds that of synonymous nucleotide substitution, implying that positive Darwinian selection has acted to diversify alleles at the amino acid level. The MSA-1 polymorphism seems to be quite ancient; the two major allelic types have been maintained for approximately 35 Myr.
authors.affiliation: Department of Biology, Institute of Molecular Evolutionary Genetics, Pennsylvania State University.
authors.forename: A L
authors.initials: AL
authors.lastname: Hughes
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics*; D000954:Antigens, Surface / Q000235:genetics; D001482:Base Composition; D020066:Merozoite Surface Protein 1; D008969:Molecular Sequence Data; D010802:Phylogeny; D010963:Plasmodium falciparum / Q000145:classification / Q000235:genetics*; D011110:Polymorphism, Genetic; D011498:Protein Precursors / Q000235:genetics*; D015800:Protozoan Proteins / Q000235:genetics*; D011995:Recombination, Genetic; D012641:Selection, Genetic; D016415:Sequence Alignment
chemical_list: D000953:Antigens, Protozoan; D000954:Antigens, Surface; D020066:Merozoite Surface Protein 1; D011498:Protein Precursors; D015800:Protozoan Proteins