New research shows that “caffeine evolved twice in nature—once in coffee, and a second time, completely independently, in tea and cacao”:
The study was co-directed by Victor Albert, a genome scientist at the University of Buffalo, and it compared the genetic code of the robusta coffee plant with the genetic code of tea and cacao plants. The researchers found that robusta plants use one kind of enzyme—known as a “methyltransferase”—to produce caffeine, while tea and cacao plants use another. Two organisms using different genetic instructions to achieve the same end is an example of convergent evolution, and the odds of it happening are long.
Why would caffeine evolve at all, never mind evolve twice? Evolutionary biologists theorize it could be protective; when caffeine-laced leaves drop to the ground, they contaminate the soil and prevent other plants from sprouting in the vicinity. Another explanation is one that might feel quite familiar to many of us, Albert explained to Nature: “caffeine habituates pollinators and makes them want to come back for more.”