Transposable Element Landscape Conserved Across Geographically Diverse Grasshopper Samples

A genomic sequencing study of the grasshopper species Trilophidia annulata has demonstrated that its genomic repeat landscape is conserved among individuals from geographically distant locations. Researchers analyzed short-read genome sequencing data collected from four individual grasshoppers sampled at distinct sites across China to characterize transposable element polymorphism in the species. The investigation established that shared transposable elements contribute substantially to the grasshopper’s overall repeat content across disparate localities. In contrast, differences observed among individual specimens are characterized by copy number variation and sequence diversification rather than large-scale genomic amplification.

Transposable elements, frequently referred to as “jumping genes”, constitute a major fraction of eukaryotic genomes and represent an increasingly recognized source of genomic variation underlying geographic divergence and local adaptation. Within insect evolutionary biology, Orthoptera is the only insect lineage known to have undergone pronounced genome gigantism, an evolutionary expansion largely driven by transposable element expansion.

To examine transposable element dynamics in a gigantic insect genome, the researchers investigated transposable element polymorphism in Trilophidia annulata, an orthopteran grasshopper species possessing a genome size measured at 9.94 gigabases. The investigation utilized short-read genome sequencing data generated from four individual grasshoppers collected from geographically distinct locations in China: Xi’an, Yan’an, Kunming, and Dali. To ensure analytical consistency and provide reliable comparative data across the different sampling sites, the short-read sequencing dataset for each individual grasshopper was independently subsampled four separate times during the research.

Across the four sampled grasshoppers, the overall genomic proportion occupied by transposable elements remained remarkably consistent, ranging between 62.41 ± 0.09 percent and 63.02 ± 0.15 percent. Despite this narrow range in total genomic proportion, the researchers detected noticeable differences when quantifying the absolute richness of distinct repetitive sequences across the sampling localities. The total number of annotated transposable element consensus sequences varied substantially by geographic origin, ranging from 24,950 ± 60.7 in the specimen collected from Xi’an to 31,003 ± 187.3 in the specimen from Dali.

An analysis of consensus sequence abundance demonstrated that approximately 30 percent of the annotated transposable element consensus sequences, representing between 7,700 and 8,700 sequences, were present at more than 10 copies per genome. Furthermore, pairwise comparisons between the sampled grasshoppers revealed that approximately half of all annotated transposable element consensus sequences were individual-specific. These individual-specific transposable elements generally occurred at low copy numbers, whereas transposable elements shared across specimens dominated the overall transposable element content across all four examined grasshopper individuals.

Analyses of accumulation patterns further indicated that shared transposable elements exhibit conserved profiles across the four geographically disparate individuals. In addition to examining shared accumulation trends across the full genome, the researchers conducted detailed phylogenetic analyses focusing specifically on the reverse transcriptase domains of long terminal repeat (LTR) retrotransposon elements.

The overall study results demonstrate that the genomic repeat landscape of Trilophidia annulata is conserved among individuals originating from different geographic locations. The empirical findings show that shared transposable elements contribute substantially to overall repetitive content, whereas differences among individuals are characterized by copy number variation and sequence diversification rather than large-scale amplification. Because this investigation evaluated short-read sequencing data across four individual specimens, these findings provide key insights into transposable element dynamics during geographic divergence and establish an essential foundational baseline for future population-level tests of adaptation.

Subject of Research: Transposable element polymorphism in the grasshopper Trilophidia annulata

Article Title: Landscape of transposable element polymorphism across geographically diverse samples of the grasshopper Trilophidia annulata

Article References: Liu, X., Nie, Y., & Huang, Y. (2026). Landscape of transposable element polymorphism across geographically diverse samples of the grasshopper Trilophidia annulata. BMC Genomics. https://doi.org/10.1186/s12864-026-13517-w

Image Credits: AI Generated

DOI: 10.1186/s12864-026-13517-w

Keywords: Trilophidia annulata, transposable elements, Orthoptera, genome gigantism, TE polymorphism, genomics, geographic divergence, repetitive DNA, Landscape, transposable, element, polymorphism