Diversity and evolutionary genetics of the three major Plasmodium vivax merozoite genes participating in reticulocyte invasion in southern Mexico

Abstract

BackgroundReported malaria cases in the Americas had been reduced to about one-half million by 2012. To advance towards elimination of this disease, it is necessary to gain insights into how the malaria parasite is evolving, including the emergence, spread and persistence of new haplotypes in affected regions. In here, the genetic diversity of the three major P. vivax merozoite genes was analyzed.MethodsFrom P. vivax-infected blood samples obtained in southern Mexico (SMX) during 2006–2007, nucleotide sequences were achieved for: the 42 kDa carboxyl fragment of the merozoite surface protein-1 (msp142), domains I-II of the apical membrane antigen-1 (ama1I-II), and domain II of the Duffy binding protein (dbpII). Gene polymorphism was examined and haplotype networks were developed to depict parasite relationships in SMX. Then genetic diversity, recombination and natural selection were analyzed and the degree of differentiation was determined as FST values.ResultsThe diversity of P. vivax merozoite genes in SMX was less than that of parasites from other geographic origins, with dbpII < ama1I-II < msp142. Ama1I-II and msp142 exposed the more numerous haplotypes exclusive to SMX. While, all dbpII haplotypes from SMX were separated from one to three mutational steps, the networks of ama1I-II and msp142 were more complex; loops and numerous mutational steps were evidenced, likely due to recombination. Sings of local diversification were more evident for msp142. Sixteen combined haplotypes were determined; one of these haplotypes not detected in 2006 was highly frequent in 2007. The Rm value was higher for msp142than for ama1I-II, being insignificant for dbpII. The dN-dS value was highly significant for ama1I-II and lesser so for dbpII. The FST values were higher for dbpII than msp142, and very low for ama1I-II.ConclusionsIn SMX, P. vivax ama1I-II, dbpII and msp142 demonstrated limited diversity, and exhibited a differentiated parasite population. The results suggest that differential intensities of selective forces are operating on these gene fragments, and probably related to their timing, length of exposure and function during reticulocyte adhesion and invasion. Therefore, these finding are essential for mono and multivalent vaccine development and for epidemiological surveillance.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-015-1266-7) contains supplementary material, which is available to authorized users.

Temporal genetic changes in Plasmodium vivax apical membrane antigen 1 over 19 years of transmission in southern Mexico

“…These values are similar to those reported for a sample of 35 parasites from 2006–2007 [36], and above those calculated for parasites from Venezuela [33] or South Korea [31], both sites of low transmission [2]. Other geographic sites with high transmission had greater genetic diversity (0.0073–0.0101), including Iran [32], India [29, 49], Sri Lanka [28], PNG [22] and Thailand [30] (Additional file 3: Table S2).…”

Diversity pattern of Duffy binding protein sequence among Duffy-negatives and Duffy-positives in Sudan

“…Comparison of the most common amino acid variants observed globally in PvDBPII revealed that Sudan isolates showed a comparatively similar pattern of minor allele frequency to Mexico isolates, but differed from other countries isolates (Papua New Guinea, Colombia, Brazil, Iran, India, Sri Lanka) (Table 1 ). Although Mexican isolates showed similar amino acid changes compared to Sudan isolates, 2 variants found in the Sudan isolates (D497N and T513K) were not identified in Mexican isolates [ 36 ].…”

“…Although Mexican isolates showed similar amino acid changes compared to Sudan isolates, 2 variants found in the Sudan isolates (D497N and T513K) were not identified in Mexican isolates [ 36 ].…”

Genetic sequence characterization and naturally acquired immune response to Plasmodium vivax Rhoptry Neck Protein 2 (PvRON2)

“…One of the greatest challenges in the development of effective vaccines which are capable of generating an efficient antigen-specific immune response is the high level of polymorphic sequences. Genetic variability has been assessed in many important P. vivax vaccine candidates, such as CSP [ 30 , 31 ], DBP [ 32 , 33 ], MSP-1 [ 33 , 34 ], MSP-3 alpha [ 35 ], MSP-4 [ 36 ], MSP-5 [ 37 ], MSP-7 [ 38 ], MSP-9 [ 39 ], RAP-1 [ 40 ], RAP-2 [ 40 ], Pvs48/45 [ 41 ], PvGCS1 [ 42 ], TRAP [ 43 ], and PvCelTOS [ 44 ].…”

“…Proteins involved in the MJ complex formation have also been characterized. PvAMA1 has been analysed and characterized in multiple studies on field isolates from different endemic area [ 29 , 33 , 45 , 46 ]. PvAMA1 is a highly polymorphic antigen [ 29 , 45 , 46 ].…”