@article {784,
	title = {Genetic variation and the recent worldwide expansion of Plasmodium falciparum.},
	journal = {Gene},
	volume = {261},
	year = {2000},
	month = {2000 Dec 30},
	pages = {161-70},
	abstract = {Plasmodium falciparum, the agent of human malignant malaria, diverged from Plasmodium reichenowi, the chimpanzee parasite, about the time the human and chimpanzee lineages diverged from each other. The absence of synonymous nucleotide variation at ten loci indicates that the world populations of P. falciparum derive most recently from one single strain, or {\textquoteright}cenancestor,{\textquoteright} which lived a few thousand years ago. Antigenic genes of P. falciparum (such as Csp, Msp-1, and Msp-2) exhibit numerous polymorphisms that have been estimated to be millions of years old. We have discovered in these antigenic genes short repetitive sequences that distort the alignment of alleles and account for the apparent old age of the polymorphisms. The processes of intragenic recombination that generate the repeats occur at rates about 10(-3) to 10(-2), several orders of magnitude greater than the typical mutational process of nucleotide substitutions. We conclude that the antigenic polymorphisms of P. falciparum are consistent with a recent expansion of the world populations of the parasite from a cenancestor that lived in tropical Africa a few thousand years ago.},
	keywords = {Animals, Antigens, Protozoan, Base Sequence, Genetic Variation, Merozoite Surface Protein 1, Molecular Sequence Data, Phylogeny, Plasmodium, Plasmodium falciparum, Polymorphism, Genetic, Protozoan Proteins, Repetitive Sequences, Nucleic Acid, RNA, Ribosomal, Sequence Homology, Nucleic Acid, Species Specificity},
	issn = {0378-1119},
	author = {Ayala, F J and Rich, S M}
}
@article {786,
	title = {The origin of antigenic diversity in Plasmodium falciparum.},
	journal = {Parasitol Today},
	volume = {16},
	year = {2000},
	month = {2000 Sep},
	pages = {390-6},
	abstract = {Most studies of genetic variability of Plasmodium falciparum have focused on protein antigens and the genes that encode them. The consensus is that populations exhibit high levels of genetic polymorphism, most notably the genes encoding surface proteins of the merozoite (Msp1, Msp2) and the sporozoite (Csp). The age and derivation of this variation is a subject that warrants further careful consideration, as discussed here by Stephen Rich, Marcelo Ferreira and Francisco Ayala.},
	keywords = {Amino Acid Sequence, Animals, Antigens, Protozoan, Base Sequence, Genes, Protozoan, Genetic Variation, Merozoite Surface Protein 1, Molecular Sequence Data, Plasmodium falciparum, Protozoan Proteins, Sequence Homology},
	issn = {0169-4758},
	author = {Rich, S M and Ferreira, M U and Ayala, F J}
}
@article {790,
	title = {Evolution of Plasmodium and the recent origin of the world populations of Plasmodium falciparum.},
	journal = {Parassitologia},
	volume = {41},
	year = {1999},
	month = {1999 Sep},
	pages = {55-68},
	abstract = {We have investigated the evolution of Plasmodium parasites by analyzing DNA sequences of several genes. We reach the following conclusions: (1) The four human parasites, P. falciparum, P. malariae, P. ovale, and P. vivax are very remotely related to each other, so that their evolutionary divergence predates the origin of the hominids; several of these parasites became associated with the human lineage by lateral transfer from other hosts. (2) P. falciparum diverged from P. reichenowi about 8 million years ago, consistently with the time of divergence of the human lineage from the apes; a parsimonious inference is that falciparum has been associated with humans since the origin of the hominids. (3) P. malariae is genetically indistinguishable from P. brasilianum, a parasite of New World monkeys; and, similarly. (4) P. vivax is genetically indistinguishable from the New World monkey parasite P. simium. We infer in each of these two cases a very recent lateral transfer between the human and monkey hosts, and explore alternative hypotheses about the direction of the transfer. We have also investigated the population structure of P. falciparum by analyzing 10 genes and conclude that the extant world populations of this parasite have evolved from a single strain within the last several thousand years. The extensive polymorphisms observed in the highly repetitive central region of the Csp gene, as well as the apparently very divergent two classes of alleles at the Msa-1 gene, are consistent with this conclusion.},
	keywords = {Amino Acid Sequence, Animals, Base Sequence, DNA, Protozoan, Evolution, Molecular, Hominidae, Humans, Merozoite Surface Protein 1, Molecular Sequence Data, Plasmodium, Plasmodium falciparum, Polymorphism, Genetic, Sequence Alignment},
	issn = {0048-2951},
	author = {Ayala, F J and Escalante, A A and Rich, S M}
}
@article {792,
	title = {The recent origin of allelic variation in antigenic determinants of Plasmodium falciparum.},
	journal = {Genetics},
	volume = {150},
	year = {1998},
	month = {1998 Sep},
	pages = {515-7},
	keywords = {Alleles, Animals, Epitopes, Genetic Variation, Merozoite Surface Protein 1, Plasmodium falciparum, Protozoan Proteins},
	issn = {0016-6731},
	author = {Rich, S M and Ayala, F J}
}
