Venegas Juan, Coñoepan William, Pichuantes Sergio, Miranda Sandra, Jercic María Isabel, Gajardo Marta, Sánchez Gittith
Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile.
Parasitol Res. 2009 Jul;105(1):191-9. doi: 10.1007/s00436-009-1386-0. Epub 2009 Apr 1.
To better understand the evolution of the etiologic agent of Chagas disease, we cloned and sequenced 25 alleles from five Tripanosoma cruzi microsatellite markers. The study of the sequences showed highly conserved alleles present in T. cruzi clones belonging to TCI, TCIIc, and TCIIe. This result was also confirmed by the phylogenetic analysis of MCLE01 allele sequences. The examination by capillary electrophoresis of six microsatellite markers from 19 T. cruzi clones showed a high proportion of the alleles found both in the TCI and TCII sublineages. The phylogenetic reconstruction of these 19 clones produced a tree with two major clusters with bootstrap support of 100% and 95%. The first cluster includes T. cruzi clones belonging to the TCI and TCIIa lineages. The second cluster is composed of TCI, TCIIc, TCIId, and TCIIe T. cruzi clones. The analysis of five microsatellite markers in the CLBrener genome showed that almost all the microsatellite markers are synteny; non-Esmeraldo and Esmeraldo haplotypes probably come from the TCIIc and TCIIb lineages. Taken together, our results are in agreement with the two hybridization events hypothesis as the origin of current T. cruzi lineages.
为了更好地理解恰加斯病病原体的进化，我们从五个克氏锥虫微卫星标记中克隆并测序了25个等位基因。序列研究表明，在属于TCI、TCIIc和TCIIe的克氏锥虫克隆中存在高度保守的等位基因。MCLE01等位基因序列的系统发育分析也证实了这一结果。通过毛细管电泳对19个克氏锥虫克隆的六个微卫星标记进行检测，结果显示在TCI和TCII亚系中均发现了高比例的等位基因。对这19个克隆进行系统发育重建，得到一棵有两个主要聚类的树，自展支持率分别为100%和95%。第一个聚类包括属于TCI和TCIIa谱系的克氏锥虫克隆。第二个聚类由TCI、TCIIc、TCIId和TCIIe克氏锥虫克隆组成。对CLBrener基因组中的五个微卫星标记进行分析，结果表明几乎所有微卫星标记都是同线的；非埃斯梅拉尔多和埃斯梅拉尔多单倍型可能分别来自TCIIc和TCIIb谱系。综上所述，我们的结果与当前克氏锥虫谱系起源的两次杂交事件假说一致。
