Chloroplast and mitochondrial DNA variation as indicator of phylogenetic relationships in the genus Coffea L.

Chloroplast and mitochondrial DNA from nine species or taxons of coffee-trees were compared as to their phylogenetic relationship by restriction endonuclease fragment analysis. Three types of chloroplast DNA (cp DNA) were detected indicating relationships as follows: (i) C. arabica, C. eugenioides; (ii) C. canephora, C. congensis, "nana" taxon; (iii) C. liberica. The mitochondrial DNA (mt DNA) separated into five types: (i) C. arabica, C. eugenioides, C. congensis; (ii) C. canephora, "nana" taxon; (iii) C. excelsa; (iv) C. liberica; (v) Paracoffea ebracteolata. The divergence in organelle DNAs agrees with the phylogenetic relationship deduced by conventional methods and is presented in some detail. Restriction patterns of the cp and mt DNAs isolated from a clone of C. arabusta have been compared to those of the parents and were found to be inherited from the mother. Cp and mt DNA analyses in the genus Coffea support the hypothesis that C. canephora diverged from C. congensis, whereafter the latter species differentiated into C. eugenioides and C. arabica.