A Predator's Genes Jumped Into Its Prey Mid-Kill

A predatory bacterium kills its prey and, in the process, passes its own genetic material into the corpse. Researchers just watched it happen for the first time.

Genes are not passed exclusively from parents to offspring. Some are mobile and can jump between species, and researchers at the Max Planck Institute for Marine Microbiology in Bremen just caught one doing exactly that, from predator to prey.

The discovery started in a slow-growing microbial community that produces methane without oxygen. Inside it, an unexpected dominant player turned up: a tiny predatory bacterium called Candidatus Velamenicoccus archaeovorus. Its prey were microorganisms that break down limonene, the compound behind the scent of oranges, into methane and carbon dioxide, including Methanothrix soehngenii, one of Earth's most important methane producers.

Found across the genomes of bacteria, plants, animals, and humans, jumping genes are a class of genetic parasites that copy and relocate themselves within a host's DNA. They travel as small RNA molecules and carry the molecular machinery needed to insert into new genomic locations, reshaping the cell's capabilities and, over time, accelerating evolution.

While analyzing the predator's genome, researcher Jens Harder found one of these, an intron, a mobile genetic element. Intron RNA had never been seen outside a cell before. He looked for it in the prey anyway. Microscopy images showed intron RNA inside living predator cells and inside dead prey cells: the mobile gene caught mid-attempt, trying to replicate inside a host its carrier had already killed.

The intron persists as stable circular RNA, pointing to a plasmid- and virus-independent route for interspecies gene transfer, a pathway nobody had documented before.

Evolution, apparently, doesn't wait for a living recipient.

Read the full story at Phys.org, June 20, 2026

Hot Take: A gene parasiting its way into a corpse via the organism that just killed it is either the most metal thing in evolutionary biology or a plot device that got cut from The Thing for being too on the nose. Either way, the textbook definition of horizontal gene transfer just got a footnote it did not see coming.