On Jun. 4, 2026, scientists from the Max Planck In­sti­tute report that genes are not passed on exclusively from parents to their offspring. Some are mobile and can also jump to other species. The direct observation of a jumping gene provides the first evidence that such genes can transfer from one species to another – from predator to prey.

Jump­ing genes are para­sites in the ge­netic ma­ter­ial of bac­teria, plants, an­im­als and hu­mans. They are re­leased into the cell as small RNA mo­lecules from ribo­nuc­leic acid (RNA) and pos­sess com­plex mech­an­isms for in­sert­ing them­selves into other parts of the ge­netic ma­ter­ial within the cell, thereby of­ten con­fer­ring new prop­er­ties on the cell and thus ac­cel­er­at­ing evol­u­tion. There are also jump­ing genes that free them­selves from the RNA us­ing an RNA en­zyme. These ri­bozymes or self-spli­cing in­trons are a spe­cial group of jump­ing genes.

It is more dif­fi­cult for a gene to jump into an­other cell or an­other spe­cies. Phylo­gen­etic ana­lyses of genes show that such jumps have taken place. Un­til now, it had been as­sumed that, for this to hap­pen, the jump­ing genes trav­elled as ‘hitch­hiker’ in the gen­omes of plas­mids or vir­uses. Now, Jens Harder and his col­leagues have made a sur­pris­ing ob­ser­va­tion.

A slowly grow­ing, meth­ane (bio­gas)-pro­du­cing en­rich­ment of bac­teria and ar­chaea har­boured an un­usual com­munity: the most abund­ant mem­ber was a very small pred­at­ory bac­terium. Candidatus Vela­men­i­co­c­cus ar­chae­o­vorus feeds on the mi­croor­gan­isms that break down li­monene, the scent of or­anges, into meth­ane and car­bon di­ox­ide. In­di­vidual cells within the fil­a­ments of Methanothrix soehngenii, the most sig­ni­fic­ant meth­ane pro­du­cer on Earth, were dead. Could Ca. Vela­men­i­co­c­cus ar­chae­o­vorus be the cause of death? To con­firm this, mo­lecules of Ca. Vela­men­i­co­c­cus ar­chae­o­vorus would need to be de­tec­ted in the dead cells.

Whilst ana­lys­ing the gen­ome of Ca. Vela­men­i­co­c­cus ar­chae­o­vorus, Jens Harder dis­covered a jump­ing gene, an in­tron. Al­though – and pre­cisely be­cause – in­tron RNA had never be­fore been ob­served out­side a cell, Jens Harder de­cided to look for the in­tron in the prey of Ca. Vela­men­i­co­c­cus ar­chae­o­vorus.

The Max Planck In­sti­tute for Mar­ine Mi­cro­bi­o­logy has de­veloped suit­able meth­ods cap­able of de­tect­ing small amounts of RNA in bac­terial cells. Fol­low­ing the de­vel­op­ment of spe­cific nuc­leic acid probes, mi­cro­scopic im­ages re­vealed the pres­ence of in­tron RNA in liv­ing cells of Ca. Vela­men­i­co­c­cus ar­chae­o­vorus and in dead cells of Methanothrix soehngenii.

Ribo­nuc­leic acids are the mes­sen­gers in liv­ing cells. They are long chain mo­lecules that carry the cell’s blue­prints from the ge­netic ma­ter­ial to the pro­tein factor­ies, and are then broken down very quickly from the end. Dead cells do not nor­mally con­tain ribo­nuc­leic acids. However, the sur­vival of in­tron RNA in cells is not sur­pris­ing, as the in­tron forms a cir­cu­lar RNA with no open ends, which is res­ist­ant to de­grad­at­ive en­zymes. “The sta­bil­ity of in­tron RNA in its ring form is a dis­tinct­ive fea­ture. In hu­mans, cir­cu­lar RNA mo­lecules in­flu­ence many meta­bolic pro­cesses, and their role in tu­mour de­vel­op­ment is cur­rently the sub­ject of in­tens­ive re­search. Ap­plic­a­tions in RNA vac­cines, for ex­ample against the Covid virus and cer­tain forms of can­cer, are also in the pipeline. Their study has shown that in mi­croor­gan­isms jump­ing genes can be trans­ferred to other spe­cies via their cir­cu­lar RNA,” says Jens Harder.