Source of coffee’s kick found in its genetic code

Caffeine genes evolved at least twice in plants

coffee plant

DOUBLE SHOT  Coffee doubled up on caffeine-making genes, possibly giving itself an evolutionary edge. Those genes evolved independently from similar ones found in tea and chocolate plants.  

Jose/Wikimedia Commons (CC BY-SA 4.0)

Coffee’s caffeine jolt evolved independently from that of tea and chocolate, a genetic analysis of the popular bean reveals.

Researchers deciphered 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 joe. Within C. canephora’s 11 chromosome pairs, the team found many duplicated genes, including ones that produce caffeine. Such duplications may let organisms make more of those genes’ products and evolve new or better-functioning proteins.

Unlike the genes that encode caffeine-synthesizing enzymes in tea and cacao plants, which are closely related, coffee’s caffeine genes are in a distinct group, the researchers report in the Sept. 5 Science. That finding indicates that caffeine production evolved at least twice.

Caffeine synthesis gave coffee grounds for evolutionary success, the researchers say. The eye-opening chemical fends off insect pests in leaves; in fruit and seeds, it delays other plant species’ germination.

Tina Hesman Saey is the senior staff writer and reports on molecular biology. She has a Ph.D. in molecular genetics from Washington University in St. Louis and a master’s degree in science journalism from Boston University.

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