Oliveira R P, Broude N E, Macedo A M, Cantor C R, Smith C L, Pena S D
Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901 Brazil.
Proc Natl Acad Sci U S A. 1998 Mar 31;95(7):3776-80. doi: 10.1073/pnas.95.7.3776.
We describe here the identification of eight polymorphic microsatellite loci with (CA)n repeats in the Trypanosoma cruzi genome based on the affinity capture of fragments using biotinylated (CA)12 attached to streptavidin-coated magnetic beads. The presence of two peaks in PCR amplification products from individual clones confirmed that T. cruzi is diploid. Hardy-Weinberg and linkage disequilibrium analyses suggested that sexual reproduction is rare or absent and that the population structure is clonal. Several strains, especially those isolated from nonhuman sources, showed more than two alleles in many loci demonstrating that they were multiclonal. The phylogenetic analysis of T. cruzi based on microsatellites revealed a great genetic distance among strains, although the strain dispersion profile in the Wagner network was in general agreement with the species dimorphism found by PCR amplification of the divergent region of the rRNA 24Salpha gene.
我们在此描述基于使用附着在链霉亲和素包被磁珠上的生物素化（CA）12对片段进行亲和捕获，在克氏锥虫基因组中鉴定出8个具有（CA）n重复序列的多态微卫星位点。来自单个克隆的PCR扩增产物中出现两个峰，证实克氏锥虫是二倍体。哈迪 - 温伯格平衡和连锁不平衡分析表明，有性繁殖很少见或不存在，且种群结构是克隆性的。几个菌株，特别是那些从非人类来源分离的菌株，在许多位点显示出两个以上的等位基因，表明它们是多克隆的。基于微卫星的克氏锥虫系统发育分析揭示了菌株之间存在很大的遗传距离，尽管在瓦格纳网络中的菌株分布概况总体上与通过rRNA 24Sα基因差异区域的PCR扩增发现的物种二态性一致。
