Coffee's caffeine buzz evolved completely differently from that of tea and chocolate, a genetic analysis of the popular bean reveals, Science News reported on Thursday.
Researchers found the genome of Coffea canephora, the second-most cultivated species of coffee and a parent of C. arabica, the source of the world's best-selling cup of coffee. Within C. canephora's 11 chromosome pairs, the team found many repeated genes, including ones that produce caffeine. Such duplications may let organisms make more of those genes' products and make or better-functioning proteins.
Coffee's caffeine genes are in a distinct group, unlike the genes that encode caffeine-synthesizing enzymes in tea and cacao plants, which are closely related, the researchers reported. That finding demonstrates that caffeine production evolved at least twice.
Caffeine synthesis gave coffee grounds for evolutionary prosperity, the researchers say. The jolting chemical fends off insect pests in leaves; in fruit and seeds, it delays other plant species' germination.
With roughly 2.25 billion cups drank every day worldwide, more than 8.7 million tons of coffee were produced last year alone. Production and export are a multibillion-dollar business, employing millions of people in more than 50 countries. It is vital to the economies of many developing countries as a tropical and subtropical crop.
"Coffee is as important to everyday early risers as it is to the global economy," another researcher, Philippe Lashermes of the French Institute of Research for Development, told Reuters.
Plant genomist Victor Albert said the coffee genome is of average size for a plant. It had about 25,500 genes responsible for different proteins.
Scientists have debated why coffee and some other plants began their outsize caffeine production.
Albert said it could get pollinators to come back again and again - like people to their favorite coffee store - or stop herbivorous insects from eating the plant's leaves. When the leaves fall to the forest floor, caffeine and other compounds may bleed into the soil and possibly inhibit the germination of the seeds of other competing plant species, he added.
