Haplotype distribution of five nuclear genes based on network genealogies and Bayesian inference indicates that Trypanosoma cruzi hybrid strains are polyphyletic

Haplotype distribution of five nuclear genes based on network genealogies and Bayesian inference indicates that Trypanosoma cruzi hybrid strains are polyphyletic

Author Tomazi, Laize Autor UNIFESP Google Scholar
Kawashita, Silvia Yukie Autor UNIFESP Google Scholar
Pereira, P. M. Autor UNIFESP Google Scholar
Zingales, Bianca Google Scholar
Briones, Marcelo Ribeiro da Silva Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Universidade de São Paulo (USP)
Abstract Chagas disease is still a major public health problem in Latin America. Its causative agent, Trypanosoma cruzi, can be typed into three major groups, T. cruzi I, T. cruzi II and hybrids. These groups each have specific genetic characteristics and epidemiological distributions. Several highly virulent strains are found in the hybrid group; their origin is still a matter of debate. The null hypothesis is that the hybrids are of polyphyletic origin, evolving independently from various hybridization events. The alternative hypothesis is that all extant hybrid strains originated from a single hybridization event. We sequenced both alleles of genes encoding EF-1 alpha, actin and SSU rDNA of 26 T. cruzi strains and DHFR-TS and TR of 12 strains. This information was used for network genealogy analysis and Bayesian phylogenies. We found T. cruzi I and T. cruzi II to be monophyletic and that all hybrids had different combinations of T. cruzi I and T. cruzi II haplotypes plus hybrid-specific haplotypes. Bootstrap values (networks) and posterior probabilities (Bayesian phylogenies) of clades supporting the monophyly of hybrids were far below the 95% confidence interval, indicating that the hybrid group is polyphyletic. We hypothesize that T. cruzi I and T. cruzi II are two different species and that the hybrids are extant representatives of independent events of genome hybridization, which sporadically have sufficient fitness to impact on the epidemiology of Chagas disease.
Keywords Trypanosoma cruzi
Chagas disease
Molecular evolution
Phylogeny
Small subunit rDNA
Language English
Sponsor Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
International Research Scholars Program of the Howard Hughes Medical Institute (HHMI).
Date 2009-01-01
Published in Genetics And Molecular Research. Ribeirao Preto: Funpec-editora, v. 8, n. 2, p. 458-476, 2009.
ISSN 1676-5680 (Sherpa/Romeo, impact factor)
Publisher Funpec-editora
Extent 458-476
Origin http://dx.doi.org/10.4238/vol8-2gmr591
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000267938300011
URI http://repositorio.unifesp.br/11600/43724

Show full item record




File

Name: WOS000267938300011.pdf
Size: 5.354Mb
Format: PDF
Description:
Open file

This item appears in the following Collection(s)

Search


Browse

Statistics

My Account