Biologists investigate what happens when traits jump between branches of the tree of life

We all must play the game of life with the cards we're dealt, so the common aphorism goes. In biology, this means organisms must compete through natural selection with the genes and anatomy they were born with. But the saying is a lie. The single-celled Paramecium bursaria hosts a symbiotic green algae that enables it to  photosynthesize. This opens up new lifestyles for the otherwise heterotrophic species [Credit: Anatoly Mikhaltsov via Wikimedia] Okay, it's not exactly a lie,...