Every second, people around the world drink more than 26,000 cups of coffee. And while some of them may care only about the taste, most use it as a way to deliver caffeine into their bloodstream. Caffeine is the most widely consumed psychoactive substance in the world.
Caffeine may be a drug, but it’s not the product of some
underworld chemistry lab; rather, it’s the result of millions of years of plant
evolution. Despite our huge appetite for caffeine, however, scientists know
little about how and why plants make it.
A new study is helping to change that. An international team
of scientists has sequenced the genome of Coffea canephora, one of the main
sources of coffee beans. By analyzing its genes, the scientists were able to
reconstruct how coffee gained the biochemical equipment necessary to make
caffeine.
The new study, published Thursday in the journal Science,
sheds light on how plants evolved to make caffeine as a way to control the
behavior of animals—and, indirectly, us.
Scientists had already determined that caffeine was also
made in other plants, like tea and cacao, by N-methyltransferases. But by
sequencing the coffee genome, Dr. Albert and his colleagues were able to make a
more detailed comparison of the genes in different species. They discovered
that in cacao, the enzymes manufacturing caffeine did not evolve from the same
ancestors as those in coffee.
...It may be a coincidence of biology that
caffeine-producing plants have a similar effect on us—toxic at high doses but
enhancing our brains at low doses. “They’re manipulating all of us,” Dr.
Mustard said.
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