RESUMO
The endemicity and transmission intensity levels of malaria are related to genetic diversity of the parasites. Merozoite surface protein 3beta [MSP3beta] is an important marker for assessing the polymorphic nature of Plasmodium vivax while it is also a vaccine candidate against the parasite. In this study we investigated the genetic structure of P. vivax population by sequence analysis of a polymorphic region of the P. vivax MSP3beta gene in isolates from Iran. Blood samples were collected from 100 patients with clinical symptoms. DNA was extracted and the target gene was amplified by polymerase chain reaction [PCR]. The sequences of 17 samples were used for sequence analysis using nucleotide Blast search and ClustalW multiple alignment. Phylogenetic tree was derived to describe the geographical branching and relationships. A large number of nucleotide insertions and deletions were observed in the sequences of polymorphic region of PvMSP3beta gene that were not specific in each biotype. Single nucleotide polymorphism [SNP] was found extensively in the sequences. The phylogenetic analysis did not show any significant geographical branching. The lack of any geographical branching and extensive polymorphism in MSP3beta gene of P. vivax isolates suggests that more investigations are needed to find a more suitable gene in order to develop a vaccine