# A nuclear ribosomal DNA pseudogene in triatomines opens a new research field of fundamental and applied implications in Chagas disease

## TL;DR

A new nuclear ribosomal DNA pseudogene in triatomine insects could help understand and control Chagas disease.

## Contribution

Discovery of a novel pseudogene with potential applications in triatomine classification and Chagas disease control.

## Key findings

- The pseudogene 'ps(5.8S+ITS-2)' shows structural differences compared to functional rDNA sequences.
- Pseudogene-based phylogenetic trees have higher consistency and retention index values.
- Variation in pseudogene amount may relate to triatomine fitness and adaptability.

## Abstract

A pseudogene, designated as "ps(5.8S+ITS-2)", paralogous to the 5.8S gene and
internal transcribed spacer (ITS)-2 of the nuclear ribosomal DNA (rDNA), has been
recently found in many triatomine species distributed throughout North America,
Central America and northern South America. Among characteristics used as criteria
for pseudogene verification, secondary structures and free energy are highlighted,
showing a lower fit between minimum free energy, partition function and centroid
structures, although in given cases the fit only appeared to be slightly lower. The
unique characteristics of "ps(5.8S+ITS-2)" as a processed or retrotransposed
pseudogenic unit of the ghost type are reviewed, with emphasis on its potential
functionality compared to the functionality of genes and spacers of the normal rDNA
operon. Besides the technical problem of the risk for erroneous sequence results, the
usefulness of "ps(5.8S+ITS-2)" for specimen classification, phylogenetic analyses and
systematic/taxonomic studies should be highlighted, based on consistence and
retention index values, which in pseudogenic sequence trees were higher than in
functional sequence trees. Additionally, intraindividual, interpopulational and
interspecific differences in pseudogene amount and the fact that it is a pseudogene
in the nuclear rDNA suggests a potential relationships with fitness, behaviour and
adaptability of triatomine vectors and consequently its potential utility in Chagas
disease epidemiology and control.