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, 11 (6), e0157901

Deciphering the Draft Genome of Toxoplasma Gondii RH Strain


Deciphering the Draft Genome of Toxoplasma Gondii RH Strain

Yee-Ling Lau et al. PLoS One.


Toxoplasmosis is a widespread parasitic infection by Toxoplasma gondii, a parasite with at least three distinct clonal lineages. This article reports the whole genome sequencing and de novo assembly of T. gondii RH (type I representative strain), as well as genome-wide comparison across major T. gondii lineages. Genomic DNA was extracted from tachyzoites of T. gondii RH strain and its identity was verified by PCR and LAMP. Subsequently, whole genome sequencing was performed, followed by sequence filtering, genome assembly, gene annotation assignments, clustering of gene orthologs and phylogenetic tree construction. Genome comparison was done with the already archived genomes of T. gondii. From this study, the genome size of T. gondii RH strain was found to be 69.35Mb, with a mean GC content of 52%. The genome shares high similarity to the archived genomes of T. gondii GT1, ME49 and VEG strains. Nevertheless, 111 genes were found to be unique to T. gondii RH strain. Importantly, unique genes annotated to functions that are potentially critical for T. gondii virulence were found, which may explain the unique phenotypes of this particular strain. This report complements the genomic archive of T. gondii. Data obtained from this study contribute to better understanding of T. gondii and serve as a reference for future studies on this parasite.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.


Fig 1
Fig 1. Genome comparison of T. gondii RH, GT1, ME49 and VEG strains.
Abbreviation: TOXME: T. gondii ME49 strain; TOXVE: T. gondii VEG strain; TOXGT: T. gondii GT1 strain; TOXRH: T. gondii RH strain.
Fig 2
Fig 2. Phylogeny tree in circular format representing genes related to the parasite gene families of T. gondii.
Different colors represent the various parasite gene families.
Fig 3
Fig 3. Circos plot illustrating the levels of synteny among genomes of different T. gondii strains.
Outer ring represents chromosomes of each strain, with the labelling of respective chromosome numbering. The scale marks on the chromosome represent 1Mb. The color bands represent syntenic blocks between the chromosomes under comparison with the chromosomes of T. gondii RH. The blue lines within the chromosome blocks of T. gondii RH indicate the T. gondii RH-unique genes identified as part of the orthologous gene study.

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Grant support

This research project was supported by University of Malaya High Impact Research (HIR) Grant UM-MOHE (UM.C/HIR/MOHE/MED/16) from the Ministry of Higher Education, Malaysia.