All Arabica Coffee Descends From One Plant

The coffee in your cup almost certainly comes from Coffea arabica, which supplies roughly 60% of global production. Yet genetically, every Arabica tree on the planet is nearly identical, because the entire species traces back to one ancestral plant.

That plant was an accident. Arabica arose when two different coffee species, Coffea canephora (robusta) and Coffea eugenioides, hybridised and doubled their chromosomes in a single rare event. Genomic analysis published in Scientific Reports in 2020 dates this allopolyploidisation to roughly 10,000 to 20,000 years ago — far more recent than earlier estimates of hundreds of thousands of years.

A single “super individual” gave rise to a species now grown across millions of hectares.

Because everything descends from that one founder, Arabica carries the lowest genetic diversity of any major crop. Its nucleotide diversity measures an order of magnitude below its parent species. That uniformity is a hidden fragility: with little variation to draw on, Arabica is unusually vulnerable to disease and a warming climate, pushing breeders toward its wilder relatives.