Jolts from electric eels cause fish to absorb free-floating DNA

Think of it as a sort of superhero origin story for zebrafish: Getting zapped by electric eels can allow them to acquire new DNA—and new abilities—researchers reported yesterday in PeerJ. Scientists working with genetic engineering sometimes use electricity to open temporary holes in cell membranes to allow foreign DNA to enter. To find out whether a version of this phenomenon can happen in nature, the team put electric eels (Electrophorus electricus, pictured) and larvae from zebrafish (Danio rerio) into a tank together, along with free-floating genes that code for a green fluorescent protein. After a day swimming amid the eels’ electric shocks, some larvae started to glow green, New Scientist reports, indicating their cells had taken in and begun to express the foreign genes. The newly acquired DNA degraded quickly—the larvae only glowed for about a week—but it caused scientists to wonder: Could a wild animal acquire genes in this way and pass them to its offspring? Researchers aren’t yet sure, but if so, they say it could introduce new mutations that influence the species’ evolution.