Phylogenetic relationships of European and African Ericas

The genus Erica (Ericeae, Ericoideae, Ericaceae) occurs in Europe, the Middle East, and Africa. Southern Africa has the largest number of species, especially at the southern tip of the continent. This narrow north-south distribution is unique in the Ericaceae and has fueled speculation about the origin of Erica species. Phylogenetic relationships among selected species of Erica were investigated in order to determine whether the origin of this genus lies in Europe or Africa. Three regions of DNA, one from the nuclear genome (nrITS) and two from the chloroplast (rbcL-atpB spacer and matK), were selected as sources of molecular data because of their previously demonstrated utility within the Ericaceae. Parsimony analysis indicates a monophyletic group of African taxa derived from within the European taxa. Erica arborea has a broad geographic range occurring in both Europe and Africa and is sister to the African clade, indicating that the common ancestor of both E. arborea and the Cape African taxa was also widespread across both continents. This common ancestor probably expanded its range into Africa after the establishment of the connection between Europe and Africa during the mid-Miocene.