A genome-wide analysis of genetic diversity in Trypanosoma cruzi intergenic regions.
BACKGROUND
Trypanosoma cruzi is the causal agent of Chagas Disease. Recently, the genomes of representative strains from two major evolutionary lineages were sequenced, allowing the construction of a detailed genetic diversity map for this important parasite. However this map is focused on coding regions of the genome, leaving a vast space of regulatory regions uncharacterized in terms of their evolutionary conservation and/or divergence.


METHODS
Using data from the hybrid CL Brener and Sylvio X10 genomes (from the TcVI and TcI Discrete Typing Units, respectively), we identified intergenic regions that share a common evolutionary ancestry, and are present in both CL Brener haplotypes (TcII-like and TcIII-like) and in the TcI genome; as well as intergenic regions that were conserved in only two of the three genomes/haplotypes analyzed. The genetic diversity in these regions was characterized in terms of the accumulation of indels and nucleotide changes.


RESULTS
Based on this analysis we have identified i) a core of highly conserved intergenic regions, which remained essentially unchanged in independently evolving lineages; ii) intergenic regions that show high diversity in spite of still retaining their corresponding upstream and downstream coding sequences; iii) a number of defined sequence motifs that are shared by a number of unrelated intergenic regions. A fraction of indels explains the diversification of some intergenic regions by the expansion/contraction of microsatellite-like repeats.
Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico de Chascomús, Universidad de San Martín - CONICET, Sede San Marítn, Buenos Aires, Argentina.
Leonardo G
LG
Panunzi
Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico de Chascomús, Universidad de San Martín - CONICET, Sede San Marítn, Buenos Aires, Argentina.
Fernán
F
Agüero
D014355:Chagas Disease / Q000469:parasitology; D017124:Conserved Sequence; D021901:DNA, Intergenic; D016054:DNA, Protozoan / Q000235:genetics; D019143:Evolution, Molecular; D014644:Genetic Variation; D018503:Genome, Protozoan; D023281:Genomics; D014349:Trypanosoma cruzi / Q000235:genetics*
D021901:DNA, Intergenic; D016054:DNA, Protozoan