Multiple origins for Mediterranean olive (Olea europaea L-ssp europaea) based upon mitochondrial DNA polymorphisms

A study of nuclear and cytoplasmic genetic diversity of cultivated olive, o leaster and other taxa belonging to the complex O. europaea was performed. Nuclear DNA polymorphism (RAPDs) in oleaster displays a gradient between th e east and west of the Mediterranean Basin. In cultivars, the gradient is l ess visible owing to their diffusion and selection. Furthermore, three mito types (ME1, MOM and MCK) were detected in both cultivated olive and oleaste r. A fourth mitotype, ME2, was unique to some cultivars. The preponderant m itotype, ME1, marks the Near Eastern origin of olive in oleaster. In the we st of the Mediterranean, another mitotype, MOM, was found in most oleaster and a few cultivars. The third, MCK, was found in a few oleaster from the w est and in cultivars originating in Kabylie and Languedoc. We argue that MC K marks an ancestral Mediterranean population. The mitotypes mark independe nt cultivated olive origins which were not detected with DNA nuclear divers ity. (C) 2000 Academie des sciences/Editions scientifiques et medicales Els evier SAS.