In addition to the two species cultivated for coffee, Coffea arabica and C. canephora, the genus has a further 123 wild species, of which 112 are native to Africa and the Indian Ocean islands. Razafinarivo et al. assess the genetic diversity of 728 individuals, representing 60 species from these key areas of species’ diversity, using 13 nuclear microsatellite markers. In addition to a good relationship between morpho-taxonomic species’ delimitations and genetic units, they find an overall pattern of genotypes running from west to east across Africa and the Indian Ocean islands, with no overlap between species from the two main areas. Madagascar appears to represent a place of significant diversification in terms of allelic richness and species’ diversity.