• Genetic relationship and Evolution of Blastocystis hominis parasite by Analysis of Complete Mitochondrial Genes Region
  • amirabbas shahsavari,1,* *Vajihe abbasi,2 Seyed Mojtaba Mousavi,3 mehid zarean,4 Reza Fotouhi-Ardakani2,5
    1. Cellular and Molecular Research Center, Clinical Laboratory Science Department, Qom University of Medical Sciences, Qom, Iran.
    2. Cellular and Molecular Research Center, Clinical Laboratory Science Department, Qom University of Medical Sciences, Qom, Iran.
    3. Department of Anesthesiology, Faculty of Medicine, Qom University of Medical Sciences, Qom, Iran.
    4. Department of Parasitology and Mycology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
    5. 1. Department of Medical Laboratory Sciences, Faculty of Para-medicine, Qom University of Medical Sciences, Qom, Iran.


  • Introduction: Blastocystis hominis is a common parasite in humans and animals that has a worldwide distribution. The association between the clinical manifestation of this mysterious protozoan and its subtypes is controversial. With the analysis of 11 mitochondrial genes, we want to find out the genetic relationship between the different subtypes and help us to understand the pathogenicity of this parasite.
  • Methods: Totally all complete mitochondrial genome of the Blastocystis was extracted from the GenBank, and the genes of nad3, nad4، nadh3, nadh6, orf160, rpl14, rpl16, rps10, rps14, rps4 and rps8 were selected. Gene’s candidate after the alignment in the CLC Genomics Workbench 11, bioinformatics software. Output from selected genetic regions was based on the subtype of Blastocystis. Genetic evaluation and polymorphism diversity. Was analyzed by DnaSP5 software. Phylogeny tree was prepared by the neighbor joining method of the MEGA7 software.
  • Results: The total of 11 sequences analyzed from the GenBank 30087 bp, 35.7% of the genetic variation was observed in Blastocystis hominis subtypes. Nine genes in the complete sequence resemble to each other with gap regions that are not consistent with the logic of gene expression and suggest a large change in the type of microsatellite. The highest genetic variation was 54.6% and the lowest 27.6% in the rps4 and nad4 genes respectively. Among variable species, the highest singletone variation was 41.27% and the lowest 7.75% in the nadh3 and rpl14 genes respectively. The highest parsimony variation was 92.2% and the lowest 58.72 in the rpl14 and nadh3 genes respectively. % 64 percent. Of the total 7700 judged areas for variation in amino acid changes were 25.7% codon complex, the highest with 53.36% and the lowest 6.7%. In the rps4 and nad4 genes respectively. The total Tajima’ D statistical index is -0.218, the highest Tajima’ D is 1.624 and the lowest -0.431in rps4 and nad4 genes respectively.
  • Conclusion: High discrepancy in percentage of diversity informative site and noninformative regions in the mitochondrial genome of this parasite shows a prominent feature. The high levels of amino acid changes are also a diagnostic bargaining chip for subtyping, which indicates its high genomic variation. Blastocystis hominis mitochondrial genes have a very high genetic diversity and can be very effective in determining the subtypes of this parasite. The nad4 gene is the most protected and the rps4 gene is the most diverse gene
  • Keywords: Blastocystis hominis, mitochondrial gene, genetic diversity