Phylogenetic Analysis and Genetics Polymorphisms Evaluation of ROP8 and B1 Genes of Toxoplasma gondii in Livestock and Poultry Hosts of Yazd, Qom and Golestan Provinces of Iran

Background: A high correlation is observed between specific clonal lineages and host types in toxoplasmosis. The main objectives of this study were comparing polymorphism and evolutionary analysis of the B1 and ROP8 genes, as well as the evaluation of phylogenic and Toxoplasma gondii isolates obtained from different hosts and regions. Methods: Overall 96 brain/ diaphragm tissue samples of livestock and poultry from three provinces of Iran (cows: 9 from Yazd, 9 from Qom; sheep: 19 from Yazd, 7 from Qom; goats: 7 from Yazd, 4 from Qom; one camel from Yazd and 37 chickens, 2 roosters and one duck from Golestan) were tested during 2018-19. A nested PCR and PCR-PCR methods were developed with the B1 and ROP8 genes. Evaluation of genetic proximity, genetic diversity and evolutionary analysis were done using MEGA-X and DnaSP5 software. Thirty samples of both genes were sequenced (18 B1 and 12 ROP8 genes), and submitted to the GenBank (MN275903-MN275932). Results: Tajima's D index analyses showed that both genes were in the negative direction of evolution. The B1 gene was more sensitive than the ROP8 gene. The ROP8 gene showed better and more acceptable results in terms of the relationship between the host and the genotyping of the samples. Conclusion: The B1 gene was only an attractive target for rapid detection of T. gondii parasites, whereas the ROP8 gene due to a high level of polymorphism was able to isolate the three clonal lineages (type I, II and III), inter-types and even atypical strains from different isolates of T. gondii.