Discovery of single-stranded DNA in meteorite-derived cultures: evidence of novel genetic elements.

This study presents the first evidence of single-stranded DNA (ssDNA) sequences identified through shotgun metagenomic analysis of meteorite-derived cultures. These ssDNA sequences, predominantly isolated from the "no-hits" zone with no significant matches in existing genomic databases, exhibit conserved motifs, distinct secondary structural features, and a unique AT-rich composition. These characteristics suggest potential roles in autoreplication, molecular stabilization, and resilience under extreme conditions, consistent with extremophilic adaptations. Notably, this discovery aligns with observations of a provisionally termed New Biological Structure (NBS) detected in diverse contexts, including meteorites and biogenic materials, though its characterization lies beyond the scope of this study. The sequences were detected using a rigorous methodology that included stringent contamination controls, advanced metagenomic assembly techniques, and exhaustive taxonomic filtering to ensure robustness and minimize false positives. Their consistent detection across meteorites of varying types and geographic origins further underscores the reliability of the findings. Repeat analyses revealed specific motifs associated with potential regulatory or structural roles, while secondary structure predictions suggested configurations that could support autoreplication and stability under extreme conditions. This groundbreaking discovery highlights the potential of meteorites to harbor previously uncharacterized genomic elements, offering profound insights into molecular diversity, prebiotic chemistry, and molecular evolution. By situating these findings within the broader context of extremophilic biology and astrobiological exploration, this study establishes a foundation for investigating the structural, functional, and evolutionary implications of these sequences. Future research will also explore their relevance as biosignatures in the search for life under extreme and extraterrestrial conditions.