A consortium of scientists announced Thursday in Science that they’ve sequenced the coffee genome for the first time. By determining all of the genes that make up robusta coffee, a plant variety that accounts for about one-third of the world’s consumption, they’ve opened the door to better breeding practices — and even genetic engineering.
The researchers were most surprised by the genes used to produce caffeine. There are several theories as to why a plant would want to give its leaves and berries an energy buzz: It might be meant as a deterrent against leaf-eating bugs, to make surrounding soil less hospitable to rival seedlings, or to turn potential pollinators into happy caffeine addicts. Whatever the drive, plants such as tea, coffee and chocolate developed enzymes to make the addicting (and sometimes toxic) compound.
But when researchers compared the coffee genome to that of chocolate, they found that the enzymes used to make caffeine in the two plants aren’t closely related enough to share a common ancestor.
In other words, coffee and chocolate found their way to caffeination independently of each other. So while the reasons for evolving caffeine production are still hard to pinpoint, we know it was a valuable enough trait to inspire multiple adaptations. Scientists don’t have a genome for tea yet, so we can’t be sure whether it developed caffeine on its own, as well.
