The origin of the Afro-Mediterranean cypresses: Evidence from genetic analysis

Abstract

Only few woody species of North Africa have been the subject of biogeographical studies, despite the importance of this region, in the Mediterranean area, for the presence of hotspots of endemism and biodiversity, and of refugia. Here, we present research on the Afro-Mediterranean Cupressus spp., which have a discontinuous and fragmented distribution, resulting from population dynamics experienced during their life history. We aim to retrace their demographic history, by combining Bayesian clustering and approximate Bayesian computation (ABC) methods. The fragmentation of the cypress gene pool dates back to Pliocene, when the Mediterranean and the North African lineages separated from a common ancestor. The separation of C. atlantica and C. dupreziana dates back to the Pleistocene, when the history of C. dupreziana as relic species started. Finally, C. sempervirens var. numidica is likely endemic of Tunisia, belonging to the cypress gene pool of the central Mediterranean since the Pleistocene.