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Researchers used genetically engineered Drosophila melanogaster fruit flies with varying amounts of transposable elements (TEs) but otherwise identical genetics to demonstrate that TEs directly cause measurable phenotypic differences. The study tested 17 traits including fertility, life-history characteristics, and stress resistance, finding that populations with more TEs showed reduced hatchability and increased variation within populations. Additionally, TE content influenced how flies responded to environmental changes, establishing TEs as drivers of both baseline phenotypic variation and environment-dependent trait expression.
Why it matters
This work provides direct experimental evidence that transposable elements, often dismissed as "junk DNA," actively contribute to biodiversity and adaptive potential. Understanding TE-driven variation could inform predictions about how organisms respond to environmental changes and may have applications in evolutionary biology and agriculture.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Transposable elements (TEs) are ubiquitous repetitive DNA sequences that can mobilise within genomes and may modulate gene expression in an environment-dependent manner. TEs and the safeguarding epigenetic machinery targeting them, can be tuned by environmental fluctuations to influence gene expression by inducing genomic, epigenetic, and transcriptomic changes. Yet, the degree to which TE-driven molecular diversity translate into inter-individual phenotypic variation vs accumulating without any phenotypic consequences remains unclear. Here, we used five populations of genetically engineered Drosophila melanogaster flies that carry variable TE content but share an otherwise identical genetic background to test the phenotypic consequences of the early stages of TE accumulation. Phenotypic screenings across 17 traits (fertility-related traits, life-history traits and stress resistance tests) revealed significant differences between the populations (e.g. reduced hatchability). We also observed a notable increase in intra-population phenotypic variation for the heavily TE-burdened populations across a wide panel of traits. These results suggest considerable TE-driven inter- and intra-population phenotypic variation. Further investigation revealed that variable TE contents can influence the response to environmental changes, positioning TEs as drivers of environmentally-induced phenotypic variation in a system deprived of other sources of genetic variation. These results provide empirical evidence that TEs contribute to the heterogeneity of the environmental response and therefore represent an underlying mechanism of phenotypic variation.