期刊
INFECTION GENETICS AND EVOLUTION
卷 6, 期 1, 页码 22-31出版社
ELSEVIER
DOI: 10.1016/j.meegid.2004.12.004
关键词
Toxoplasma gondii; strains; Brazil; genotyping; PCR-RFLP; population structure
Polymerase chain reaction-restrict ion fragment length polymorphism (PCR-RFLP) at eight independent loci was used to determine the types (I, II or III) lineage of 20 Toxoplasma gondii strains isolated from humans and animals in Brazil. RH (type I, highly virulent), ME49 (type II, avirulent) and VEG (type III, avirulent) were used as reference strains. Differently from expected frequencies, all Brazilian strains showed to have recombinant genotypes, with typical alleles of types I, II or III at almost all loci assessed. The cB21-4 locus, a microsatellite marker, showed a higher allelic polymorphism with seven alleles among strains under analysis. Data have also shown that many Brazilian T gondii strains presented it new haplotype at the L363 locus. When results of the eight loci were combined, 14 schizodemes were characterized out of the 20 T gondii strains isolated in Brazil. The phenogram representing PCR-RFLP data separated Brazilian strains into two distinct genetic groups associated with murine virulence phenotype, termed groups I-A and I-B. Strains from group I-A (AS28, BV and N) that were highly virulent in BALB/c mice, were Clustered with RH reference strain. Only those strains presented the haplotype I at the L363 locus, suggesting that this could be a possible marker of highly virulent strains. Strains from group I-B (cystogenic strains) showed a more heterogeneous behavior regarding virulence: a few of them (EGS, RAR, SAR D5 and D6) were virulent, others (C4, P and D8) avirulent and most of them (D1, D2, D3, D4, D7, EFP, CH1, CH2 and CH3) intermediate virulent in mice. A significant linkage disequilibrium was observed in the population surveyed. However, the role of sexual recombination in the population structure of T. gondii in Brazil seems to be more central than in Europe and North America, where most studies have been performed. (c) 2005 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据