# Simple Sequence Repeats (SSRs) and Telomeric Analysis in Somatic Organs of Reproductive and Non-Reproductive Castes of Termite Reticulitermes chinensis

## TL;DR

This study explores how simple sequence repeats and telomeres in termites relate to aging and longevity, revealing unique genetic mechanisms in social insects.

## Contribution

The study identifies a unique telomere maintenance mechanism in Reticulitermes chinensis, decoupling telomere length from aging.

## Key findings

- Tri-nucleotide repeats were the most prevalent SSRs in R. chinensis, with AC/GT being the most common motif.
- Telomere lengths in R. chinensis showed no correlation with lifespan differences among castes, suggesting a unique maintenance mechanism.
- The TTAGG telomeric repeat motif was confirmed at chromosome ends using fluorescence in situ hybridization.

## Abstract

This study investigates the transcriptome of Reticulitermes chinensis, focusing on the roles of simple sequence repeats (SSRs) and telomeres in the aging process. Using the Illumina HiSeq 4000 platform, 103 million sequence reads were generated and processed, yielding 184,436 unigenes. Genomic repeat sequences were assembled and analyzed using tools such as Trinity and RepeatExplorer. The findings underscore the critical role of telomere integrity in cellular aging and shed light on the molecular mechanisms underlying longevity in social insects.

The study of Reticulitermes chinensis offers valuable insights into insect aging and longevity, focusing on telomere biology and simple sequence repeats (SSRs). Telomeres, the protective cap at chromosome ends, are often linked to cellular aging and lifespan. Through transcriptomic analysis using the RepeatExplorer tool, a total of 10,740 SSR loci were identified, encompassing di-, tri-, tetra-, penta-, and hexa-nucleotide motifs. Among these, tri-nucleotide repeats were the most prevalent (2702), with prominent motifs including AC/GT (21.91%), AAG/CTT (8.49%), and AGC/CTG (8.2%). The identified SSRs serve as valuable genetic markers for taxonomy, phylogenetic, and population genetics. A telomeric sequence array featuring the TTAGG repeat motif was also discovered, with fluorescence in situ hybridization (FISH) confirming its localization at chromosome ends. Telomere lengths R. chinensis ranged from tens to hundreds of kilobases but showed no significant correlation with lifespan differences among termite castes. All castes had the same telomere length. This finding suggests that R. chinensis may possess a unique telomere maintenance mechanism, decoupling telomere length from aging and challenging the conventional view that shorter telomeres are indicative aging. It is hypothesized that telomerase activity plays a critical role in preserving telomere integrity in this species. These findings underscore the complexity and evolutionary adaptations of telomere biology in social insects. Moreover, the variation and organization of SSRs in R. chinensis provide a rich genetic resource for genome mapping, evolutionary research, and population genetics. This study sheds light on telomere dynamics and genetic diversity in termites, opening new pathways for research in evolutionary biology and the molecular mechanisms of aging.