Phylogenetic study of protozoan Toxoplasma gondii using Cytochrome b and Gra20 genes

Bozorgi, Soghra; Nabian, Sedigheh; Habibi, Gholamreza; Afshari, Asghar; Shahedi, Amin; Nasiri, Vahid

doi:10.32592/ARI.2025.80.4.1029

Phylogenetic study of protozoan Toxoplasma gondii using Cytochrome b and Gra20 genes

Document Type : Original Articles

Authors

¹ Department of Parasite Vaccine Research and Production, Razi Vaccine and Serum Research Institute, Agriculture Research, Education, and Extension Organization (AREEO), Karaj, Iran.

² Department of Ticks and Tick-borne Diseases (RCTTD), Faculty of Veterinary Medicine, University of Tehran, Iran.

³ Department of Parasitology, Razi Vaccine and Serum Research Institute, Agriculture Research, Education, and Extension Organization (AREEO), Karaj, Iran.

10.32592/ARI.2025.80.4.1029

Abstract

Toxoplasma gondii is an obligate intracellular protozoan in the phylum Apicomplexa. In addition to humans, toxoplasmosis can also cause serious diseases in livestock, leading to significant economic losses. The Toxoplasma gondii parasite is transmitted through the feces of its primary host, the Felidae family. The use of molecular methods with high sensitivity has made it possible to detect and study microorganisms. In this study the cytochrome b and dense granule 20 (Gra20) genes were utilized for studying Toxoplasma gondii parasites.
After collecting 29 animal samples of Toxoplasma gondii, the PCR method was applied to evaluate the presence of Gra20 and cytochrome b genes. The sequence of 11 samples was acceptable and submitted in the NCBI database. Mega X software was utilized to create the phylogenetic tree. In addition, the genetic diversity was studied using the RFLP-PCR assay for Gra6 gene.
Assessment of the bands obtained from PCR showed that the bands related to cytochrome b are found in all species of the Sarcocystidae family, but the bands related to the Gra20 gene are specific to Toxoplasma gondii. In the phylogenic tree, there was a closer relationship between Iranian isolates of Toxoplasma gondii and French strain of Toxoplasma gondii. Type I was determined as the genetic type of protozoan Toxoplasma gondii isolated from Iran.
Based on the results, the cytochrome b gene was considered as a general gene for recognizing different species of the Sarcocystidae family, however divergence was seen in the Gra20 gene, which is considered a particular gene for Toxoplasma gondii.

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