PHYLOGENETIC ANALYSIS OF CHLOROPLAST DNA VARIATION IN COFFEA L

The trnL-trnF intergenic spacer of cpDNA has been sequenced from 38 tr ee samples representing 23 Coffea taxa and the related genus Psilanthu s. These sequences were used for phylogenetic reconstruction using par simony analyses. The results suggest a radial mode of speciation and a recent origin in Africa for the genus Coffea. Phylogenetic relationsh ips inferred from the cpDNA analysis suggest several major clades, whi ch present a strong geographical correspondence (i.e., west Africa, ce ntral Africa, east Africa, and Madagascar). The overall results agree well with the phylogeny previously inferred from nuclear genome data. However, several inconsistencies are observed among taxa endemic to we st Africa, suggesting the occurrence of introgressive hybridization, E vidence is also obtained for the genetic origin of the allotetraploid species C. arabica. (C) 1998 Academic Press.