TY - JOUR
T1 - Evidence of substantial recombination among Trypanosoma cruzi II strains from Minas Gerais
AU - Baptista, Rodrigo de Paula
AU - D'Ávila, Daniella Alchaar
AU - Segatto, Marcela
AU - Valle, Ítalo Faria do
AU - Franco, Glória Regina
AU - Valadares, Helder Magno Silva
AU - Gontijo, Eliane Dias
AU - Galvão, Lúcia Maria da Cunha
AU - Pena, Sérgio Danilo Junho
AU - Chiari, Egler
AU - Machado, Carlos Renato
AU - Macedo, Andréa Mara
N1 - Funding Information:
We thank Fernanda Kehdy and Giordano Souza from the Laboratório de Diversidade de Genética Humana, Universidade Federal de Minas Gerais for their help in part of the population analyses. We also thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) , Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) , and Fundação de Amparo à Pesquisa de Minas Gerais (FAPEMIG) for supporting this study.
PY - 2014/3
Y1 - 2014/3
N2 - Due to the scarcity of evidence of sexuality in Trypanosoma cruzi, the causative agent of Chagas disease, it has been general accepted that the parasite reproduction is essentially clonal with infrequent genetic recombination. This assumption is mainly supported by indirect evidence, such as Hardy-Weinberg imbalances, linkage disequilibrium and a strong correlation between independent sets of genetic markers of T. cruzi populations. However, because the analyzed populations are usually isolated from different geographic regions, the possibility of population substructuring as generating these genetic marker imbalances cannot be eliminated. To investigate this possibility, we firstly compared the allele frequencies and haplotype networks using seven different polymorphic loci (two from mitochondrial and five from different nuclear chromosomes) in two groups of TcII strains: one including isolates obtained from different regions in Latin America and the other including isolates obtained only from patients of the Minas Gerais State in Brazil. Our hypothesis was that if the population structure is essentially clonal, Hardy-Weinberg disequilibrium and a sharp association between the clusters generated by analyzing independent markers should be observed in both strain groups, independent of the geographic origin of the samples. The results demonstrated that the number of microsatellite loci in linkage disequilibrium decreased from 4 to 1 when only strains from Minas Gerais were analyzed. Moreover, we did not observed any correlation between the clusters when analyzing the nuclear and mitochondrial loci, suggesting independent inheritance of these markers among the Minas Gerais strains. Besides, using a second subset of five physically linked microsatellite loci and the Minas Gerais strains, we could also demonstrate evidence of homologous recombination roughly proportional to the relative distance among them. Taken together, our results do not support a clonal population structure for T. cruzi, particularly in TcII, which coexists in the same geographical area, suggesting that genetic exchanges among these strains may occur more frequently than initially expected.
AB - Due to the scarcity of evidence of sexuality in Trypanosoma cruzi, the causative agent of Chagas disease, it has been general accepted that the parasite reproduction is essentially clonal with infrequent genetic recombination. This assumption is mainly supported by indirect evidence, such as Hardy-Weinberg imbalances, linkage disequilibrium and a strong correlation between independent sets of genetic markers of T. cruzi populations. However, because the analyzed populations are usually isolated from different geographic regions, the possibility of population substructuring as generating these genetic marker imbalances cannot be eliminated. To investigate this possibility, we firstly compared the allele frequencies and haplotype networks using seven different polymorphic loci (two from mitochondrial and five from different nuclear chromosomes) in two groups of TcII strains: one including isolates obtained from different regions in Latin America and the other including isolates obtained only from patients of the Minas Gerais State in Brazil. Our hypothesis was that if the population structure is essentially clonal, Hardy-Weinberg disequilibrium and a sharp association between the clusters generated by analyzing independent markers should be observed in both strain groups, independent of the geographic origin of the samples. The results demonstrated that the number of microsatellite loci in linkage disequilibrium decreased from 4 to 1 when only strains from Minas Gerais were analyzed. Moreover, we did not observed any correlation between the clusters when analyzing the nuclear and mitochondrial loci, suggesting independent inheritance of these markers among the Minas Gerais strains. Besides, using a second subset of five physically linked microsatellite loci and the Minas Gerais strains, we could also demonstrate evidence of homologous recombination roughly proportional to the relative distance among them. Taken together, our results do not support a clonal population structure for T. cruzi, particularly in TcII, which coexists in the same geographical area, suggesting that genetic exchanges among these strains may occur more frequently than initially expected.
KW - Clonality
KW - Population substructuring
KW - Recombination
KW - Sex reproduction
KW - Trypanosoma cruzi II
KW - Wahlund effect
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U2 - 10.1016/j.meegid.2013.11.021
DO - 10.1016/j.meegid.2013.11.021
M3 - Article
C2 - 24296011
AN - SCOPUS:84896731588
SN - 1567-1348
VL - 22
SP - 183
EP - 191
JO - Infection, Genetics and Evolution
JF - Infection, Genetics and Evolution
ER -