Evolution of tandem repeats in putative circumsporozoite protein to enhance its function: A recent and exclusive event in Plasmodium vivax in India

Background: The hitchhiking model of molecular evolution proposes that linked non-coding regions also undergo fixation, while fixing a beneficial allele in a population. This concept can be applied to identify loci with functional and evolutionary significance. Putative circumsporozoite protein in P...

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Main Authors: Manoswini Dash, Veena Pande, Aparup Das, Abhinav Sinha
Format: Article
Language:English
Published: Elsevier 2025-01-01
Series:Current Research in Microbial Sciences
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Online Access:http://www.sciencedirect.com/science/article/pii/S2666517425000938
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Summary:Background: The hitchhiking model of molecular evolution proposes that linked non-coding regions also undergo fixation, while fixing a beneficial allele in a population. This concept can be applied to identify loci with functional and evolutionary significance. Putative circumsporozoite protein in Plasmodium vivax (PvpuCSP) identified following the molecular hitchhiking model, holds evolutionary significance. Methods: We investigated the extent of genetic polymorphism in PvpuCSP and the role of natural selection which shapes the genetic composition and maintains the diversity in P. vivax isolates from India. Results: Sequencing the putative CSP of P. vivax (PvpuCSP) in 71 isolates collected from P. vivax endemic regions of India, revealed a well-conserved N- and C-terminal, constituting around 80 % of the gene. PCR amplification and sequencing validated extensive diversity in the repeat region, ranging from 1.8 to 2.2 kb towards the C-terminal, identifying 37 different alleles from 71 samples. Conclusions: The recent and exclusive accumulation of repeats in the putative circumsporozoite protein within Indian P. vivax highlights its highly variable length polymorphism, making it a potential marker for estimating diversity and infection complexity. Episodic diversifying selection in the PvpuCSP repeat region, supported by statistically significant p-values and likelihood ratios, contributes to amino acid diversity at various phylogenetic levels. Our previous systematic computational study proposed PvpuCSP as E3-ubiquitin ligase, and the observed diversity may facilitate adaptation to different ubiquitination-related interactions, though this remains to be experimentally validated.
ISSN:2666-5174