Allelic dimorphism of Plasmodium vivax gam-1 in the Indian subcontinent

A study was designed to assess the diversity of Pvgam-1 among field isolates from India, using a nested PCR assay. Field isolates were collected from different regions of the country and the observed variability was confirmed by sequencing data.Both Belem and Chesson type alleles were present either exclusively or in mixed form among isolates of all 10 study sites. The Belem type allele was predominant, occurring in 67% of isolates. The proportion of isolates showing the mixed form (both Belem and Chesson type alleles occurring together in the same isolate) was about 13 overall (up to 38.5% in some isolates). Sequencing of the PCR-amplified Belem and Chesson type alleles confirmed the PCR results. Among the 10 study sequences, 11 polymorphic sites and four singleton variations were observed. All the nucleotide substitutions were non-synonymous.Study shows limited diversity of Pvgam-1 marker in Indian isolates with well representation of both Belem and Chesson type alleles.Plasmodium vivax is the most widespread human malaria parasite and is responsible for 70–80 million cases annually [1]. In India, it is the most prevalent of human malaria parasites, contributing 50–55% cases of malaria each year. P. vivax infections are rarely fatal but impact heavily on personal health placing a considerable economic burden upon individuals and communities [2].Malaria eradication programmes are facing a formidable challenge due to the spread of drug resistance and the complex population genetic structure of malaria parasites. Genetic polymorphism is an inevitable component of a complex organism, especially in multistage infectious organisms such as malaria parasites. Understanding the genetic population structure of the parasites may provide valuable information for effective malaria control strategies. There have been few studies on genetic polymorphism in P. vivax, first because more work has been done on the more virulent human malaria parasite, Plasmodium falciparum, and seco