Differential Spreading of Microsatellites in Holocentric Chromosomes of Chagas Disease Vectors: Genomic and Evolutionary Implications

Simple Summary This study analyzed microsatellite distribution in the holocentric chromosomes of Triatominae, Chagas disease vectors. Using a non-denaturing FISH technique, 16 microsatellites were examined across 25 species from the Triatomini and Rhodniini tribes. Three hybridization patterns emerged: strong signals in specific regions, dispersed signals based on microsatellite abundance and the absence of signals in certain regions or chromosomes. Rhodniini had weak and scattered signals, indicating low microsatellite abundance, while Triatomini showed diverse and abundant patterns, suggesting their significance in genomes. Particularly, all Triatomini species exhibited a high abundance of GATA repeats in the Y chromosome, unlike Rhodniini. This suggests the ancestral trait is specific to Triatomini. The study provides insights into microsatellite composition and distribution in Triatominae genomes, shedding light on their evolutionary processes and relationships with other reduviid groups.Abstract This study focused on analyzing the distribution of microsatellites in holocentric chromosomes of the Triatominae subfamily, insect vectors of Chagas disease. We employed a non-denaturing FISH technique to determine the chromosomal distribution of sixteen microsatellites across twenty-five triatomine species, involving five genera from the two principal tribes: Triatomini and Rhodniini. Three main hybridization patterns were identified: strong signals in specific chromosomal regions, dispersed signals dependent on microsatellite abundance and the absence of signals in certain chromosomal regions or entire chromosomes. Significant variations in hybridization patterns were observed between Rhodniini and Triatomini species. Rhodniini species displayed weak and scattered hybridization signals, indicating a low abundance of microsatellites in their genomes. In contrast, Triatomini species exhibited diverse and abundant hybridization patterns, suggesting that microsatellites are a significant repetitive component in their genomes. One particularly interesting finding was the high abundance of GATA repeats, and to a lesser extent AG repeats, in the Y chromosome of all analyzed Triatomini species. In contrast, the Y chromosome of Rhodniini species did not show enrichment in GATA and AG repeats. This suggests that the richness of GATA repeats on the Y chromosome likely represents an ancestral trait specific to the Triatomini tribe. Furthermore, this information can be used to elucidate the evolutionary relationships between Triatomini and other groups of reduviids, contributing to the understanding of the subfamily's origin. Overall, this study provides a comprehensive understanding of the composition and distribution of microsatellites within Triatominae genomes, shedding light on their significance in the evolutionary processes of these species.

Automated summary

This study analyzed the distribution of microsatellites in the holocentric chromosomes of Triatominae, which are vectors of Chagas disease. The results showed that there are differences in microsatellite distribution between Triatomini and Rhodniini species, with higher abundance and diversity in Triatomini. Additionally, a high abundance of GATA repeats was found in the Y chromosome of all Triatomini species, suggesting it is an ancestral trait specific to Triatomini.