title: Genetic variability of Brazilian Toxoplasma gondii strains detected by random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) and simple sequence repeat anchored-PCR (SSR-PCR).
abstract: The genetic variability of 19 Toxoplasma gondii strains isolated from humans and animals in Brazil was detected by both random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) and simple sequence repeat anchored-PCR (SSR-PCR) for the first time. Two reference strains, RH (highly virulent) and ME49 (avirulent), were submitted to both assays. Besnoitia sp., Plasmodium falciparum and Babesia bigemina were used as outgroups. RAPD-PCR and SSR-PCR profiles were used for building phenetic trees by unweighted pair group method with arithmetic averages (UPGMA). Phenograms built with TREECONW software showed great similarity in the topology of the trees. Both phenograms presented two major clusters that grouped T. gondii strains according to their murine virulence. The strains AS28, BV and N, which are highly virulent for BALB/c mice, were clustered with the reference strain RH, the highly virulent strain of T. gondii that has been most commonly studied. The group formed by the cystogenic strains showed that the strains which presented a level of virulence more similar to that of ME49 strain (avirulent) also presented a closer genetic relationship. Genetic variation within each lineage was significantly lower (P < 0.05) than that between the lineages. Regarding outgroups, Besnoitia sp. presented the closest relationship to T. gondii while P. falciparum was the most distant. The results presented here demonstrate that intraspecific genetic variability separates Brazilian T. gondii strains into two groups which correlate with murine virulence phenotype.
authors.affiliation: Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, MG, Brazil.
authors.forename: Adriana de Melo
authors.initials: Ade M
authors.lastname: Ferreira
authors.forename: Ricardo Wagner A
authors.initials: RW
authors.lastname: Vitor
authors.forename: Ana Carolina A V
authors.initials: AC
authors.lastname: Carneiro
authors.forename: Geane Peroni
authors.initials: GP
authors.lastname: Brandão
authors.forename: Maria Norma
authors.initials: MN
authors.lastname: Melo
mesh_terms: D000818:Animals; D001938:Brazil; D016054:DNA, Protozoan / Q000032:analysis / Q000302:isolation & purification; D014644:Genetic Variation; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D018895:Microsatellite Repeats; D016133:Polymerase Chain Reaction; D019105:Random Amplified Polymorphic DNA Technique; D014122:Toxoplasma / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D014774:Virulence
chemical_list: D016054:DNA, Protozoan