The researchers said this suggests that caffeine production developed independently in coffee.

If this trait had been inherited from a common ancestor, the enzymes would have been more similar between species, they added.

In an accompanying article, Dani Zamir of the Hebrew University of Jerusalem highlighted the importance of translating the coffee genome into new tools for coffee breeding, particularly as the diversity of coffee plants globally declines.

Zamir urged scientists to share data on traits like aroma and flavor to ensure variation among coffee plant species persists, which will in turn help to mitigate the effects of unstable climate and plant diseases on this crop.

"The danger to the coffee crop should provide an incentive for all stakeholders to initiate international collaborations in genomic-assisted breeding projects and germ plasm conservation with poor, coffee-exporting countries," Zamir wrote.

Scientists from other organizations, particularly the French Institute of Research for Development and the French National Sequencing Center, also contributed to the study, along with researchers from public and private organizations in the United States, France, Italy, Canada, Germany, China, Spain, Indonesia, Brazil, Australia and India.

With more than 2.25 billion cups consumed daily worldwide, coffee is the principal agricultural product of many tropical countries.

According to estimates by the International Coffee Organization, more than 8.7 million tons of coffee were produced in 2013, revenue from exports amounted to 15.4 billion U.S. dollars in 2009- 2010, and the sector employed nearly 26 million people in over 50 countries during 2010.