Unidad de Epidemiología Molecular (UEM), Instituto de Patología Experimental, Universidad Nacional de Salta-CONICET, Av. Bolivia 5150, CP4400, Salta, Argentina.
Infect Genet Evol. 2011 Mar;11(2):300-7. doi: 10.1016/j.meegid.2010.10.020. Epub 2010 Nov 24.
Internal and geographical clustering within Trypanosoma cruzi I (TcI) has been recently revealed by using Multilocus Microsatellite Typing and sequencing of the Spliced-Leader Intergenic Region (SL-IR). In the present work, 14 isolates and 11 laboratory-cloned stocks obtained from a geographically restricted area in Chaco Province, Argentina, were analyzed by PCR and sequencing of SL-IR. We were able to differentiate 8 different genotypes that clustered into 4 groups. One of these groups was classified within the formerly described haplotype A and another one within the recently described SL-IR group E. Both were phylogenetically well-supported. In contrast, none of the stocks from the Chaco province were grouped within the cluster previously named haplotype D despite the fact that they shared a similar microsatellite motif in the SL-IR. No evidence of recombination or gene conversion within these stocks was found. On the other hand, multiple ambiguous alignments in the microsatellite region of SL-IR, affecting the tree topology and relationships among groups were detected. Finally, since there are multiple copies of the SL-IR, and they are arranged in tandem, we discuss how molecular processes affecting this kind of sequences could mislead phylogenetic inference.
内部和地理聚类在克氏锥虫 I（TcI）最近被揭示使用多位点微卫星分型和拼接的领导基因间区（SL-IR）测序。在目前的工作中，14 个分离株和 11 个实验室克隆株从阿根廷查科省的一个地理限制区获得，通过 PCR 和 SL-IR 测序进行分析。我们能够区分 8 种不同的基因型，这些基因型分为 4 组。其中一组被归类为先前描述的单倍型 A，另一组被归类为最近描述的 SL-IR 组 E。这两组都得到了很好的系统发育支持。相比之下，查科省的这些库存没有被归类为以前命名的单倍型 D 簇，尽管它们在 SL-IR 中共享一个类似的微卫星基序。在这些库存中没有发现重组或基因转换的证据。另一方面，在 SL-IR 的微卫星区域检测到多个模糊的比对，影响了树拓扑和组之间的关系。最后，由于 SL-IR 有多个拷贝，并且它们串联排列，我们讨论了影响这种序列的分子过程如何误导系统发育推断。
