Evolutionary and phylogenetic analyses of the barcoding region suggest geographical relationships among Blastocystis sp., ST3 in humans

• Published in: Infection, genetics and evolution Vol. 96; p. 105151
• Main Authors: Nemati, Sara, Falahati Anbaran, Mohsen, Mohammad Rahimi, Hanieh, Hosseini, Monireh Sadat, Aghaei, Sara, Khalili, Negar, Mirjalali, Hamed, Zali, Mohammad Reza
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-12-2021
• Subjects: Bayes Theorem; Biological Evolution; Blastocystis; Blastocystis - genetics; DNA Barcoding, Taxonomic; Evolution, Molecular; Genes, Protozoan; Geography; Haplotype network; Haplotypes; Nucleotide diversity; Phylogeny; Population analysis; Subtype 3; Population analysis; Haplotype network; Blastocystis; Subtype 3; Nucleotide diversity
• ISSN: 1567-1348; 1567-7257
• DOI: 10.1016/j.meegid.2021.105151

Blastocystis sp., has 21 distinct subtypes of which ST3 thought to be the most prevalent subtype. This study aims to analyze the global variations of ST3. In total, 496 sequences with more than 400 nucleotides from Asia, Europe, Africa, and America were included in this study. Results show that allele 34 was the most prevalent allele in all continents. The lowest and highest allele diversity were observed in Europe and Africa, respectively. The nucleotide diversity ranged from 0.0077 in Europe to 0.02 in Africa, and haplotype diversity ranged from 0.461 in America to 0.6 in Africa. The haplotype network and Bayesian structure showed at least two major clusters including Asia and Europe-Africa-America. Tajima's D values for all continents were negative and statistically significant, indicating an excess of rare nucleotide variants. Similarly, the Fu's FS test showed negative values for all regions, indicating an excess of rare haplotypes. Pairwise FST exhibited a high genetic differentiation between Asia and other continents. Mismatch analysis for all populations showed a unimodal distribution. Our findings indicate that there are two probable major clusters of Blastocystis sp. ST3, a cluster which is shared between Europe, Africa, and America, and a cluster which is restricted to Asia.
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•Sequencing of the barcoding region is the standard classification method for Blastocystis sp.•The haplotype network and Bayesian structure showed at least two major clades.•Pairwise Fst exhibited a high genetic difference between Asia and other continents.