Researchers who've sequenced the genome of the most cultivated variety of coffee say they've learned a lot about how it came to independently create caffeine, source of our daily wakeup call.
Although caffeine is present in coffee, tea and chocolate, scientists say the genome unraveling suggests coffee evolved the genes responsible for caffeine production independently of tea and chocolate, and that none of them got them from the last common ancestor plant.
The researchers have mapped the genome of robusta coffee, a variety accounting for around a third of the 2.5 billion cups of coffee consumed around the world daily.
Caffeine has a known and measurable effect on human brain chemistry, drawing us to want to consume coffee, tea and chocolate.
"The coffee genome helps us understand what's exciting about coffee -- other than that it wakes me up in the morning," says Victor Albert of the University of Buffalo, one of the authors of the published study.
Although caffeine in coffee certainly makes it attractive -- for some, indispensable -- why the coffee plant itself needed to evolve the ability to create it is some of a mystery.
It may be to fend off leaf-eating insects, or to make the soil around a coffee plant less attractive to plant competition, or it may attract beneficial pollinators like bees and birds by turning them into attentive caffeine addicts, Albert suggests.
Or it may be a combination of all three, or something yet undiscovered, he says.
Still, he points, caffeine is obviously vital to coffee, tea and chocolate since all three have chosen a separate evolutionary path that let them be caffeine producers.
"So we're talking about plants that have been separated for a very long time that have independently evolved the capacity to make caffeine," Albert says.
Sequencing the robusta coffee may bring new breeding practices for a crop that is the top revenue-creating exports for numerous countries around the globe, the researchers say.
Or it might even allow the genetic engineering of entirely new varieties of coffee.
Ironically, once such desirable variety could be an evolutionary step backward, to a time when coffee was without caffeine.
"[Genetic engineering] might make it possible to knock off caffeine production in a variety of coffee plant," he says. "So to make decaf coffee, you wouldn't have to go through the process of extracting the caffeine. You could just grow coffee beans that don't make it at all."
For those that don't need that morning wakeup jolt, that is.