TY - JOUR
T1 - Plasmodium vivax
T2 - Recent world expansion and genetic identity to Plasmodium simium
AU - Lim, Chae Seung
AU - Tazi, Loubna
AU - Ayala, Francisco J.
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2005/10/25
Y1 - 2005/10/25
N2 - Plasmodium vivax causes the most geographically widespread human malaria, accounting annually for 70-80 million clinical cases throughout the tropical and subtropical regions of the world's continents. We have analyzed the DNA sequences of the Csp (circumsporozoite protein) gene in 24 geographically representative strains of P. vivax and 2 of P. simium, which parasitizes several species of New World monkeys. The Csp sequences are of two types, VK210 and VK247, which differ by three diagnostic amino acid replacements, one in each of the 5′ and 3′ terminal regions [5′ nonrepeat (NR) and 3′ NR] of the gene and in an insertion sequence that precedes the 3′ NR region. The central region of the gene consists of ≈38 repetitive "motifs," which are alternatively four and five amino acids long, which also are diagnostically different between the VK210 and VK247 types. There are very few synonymous substitutions within and between the two types of strains, which we hypothesize reflects that the worldwide spread of P. vivax is very recent. The two P. simium Csp sequences belong one to each of the two VK types and are genetically indistinguishable from the corresponding P. vivax strains, suggesting that at least two host transfers have occurred between humans and New World monkeys. We exclude as unlikely the possibility that the two types of sequences could have independently arisen in humans and platyrrhines by natural selection. There are reasons favoring each of the two possible directions of host transfer between humans and monkeys.
AB - Plasmodium vivax causes the most geographically widespread human malaria, accounting annually for 70-80 million clinical cases throughout the tropical and subtropical regions of the world's continents. We have analyzed the DNA sequences of the Csp (circumsporozoite protein) gene in 24 geographically representative strains of P. vivax and 2 of P. simium, which parasitizes several species of New World monkeys. The Csp sequences are of two types, VK210 and VK247, which differ by three diagnostic amino acid replacements, one in each of the 5′ and 3′ terminal regions [5′ nonrepeat (NR) and 3′ NR] of the gene and in an insertion sequence that precedes the 3′ NR region. The central region of the gene consists of ≈38 repetitive "motifs," which are alternatively four and five amino acids long, which also are diagnostically different between the VK210 and VK247 types. There are very few synonymous substitutions within and between the two types of strains, which we hypothesize reflects that the worldwide spread of P. vivax is very recent. The two P. simium Csp sequences belong one to each of the two VK types and are genetically indistinguishable from the corresponding P. vivax strains, suggesting that at least two host transfers have occurred between humans and New World monkeys. We exclude as unlikely the possibility that the two types of sequences could have independently arisen in humans and platyrrhines by natural selection. There are reasons favoring each of the two possible directions of host transfer between humans and monkeys.
KW - Circumsporozoite protein
KW - Clonal theory
KW - Host-parasite interactions
KW - Malaria
KW - Plasmodium population structure
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U2 - 10.1073/pnas.0507413102
DO - 10.1073/pnas.0507413102
M3 - Article
C2 - 16227436
AN - SCOPUS:27344442280
VL - 102
SP - 15523
EP - 15528
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 43
ER -