Evidence of high genetic differentiation driven by limited gene flow in a lower canopy African tropical rainforest tree species, Coula edulis Baill. (Coulaceae).

backgroundThe distribution of intra-specific genetic diversity in tropical African forest tree species often reveals discontinuities in the form of genetic clusters distributed in parapatry or allopatry. To date, most population genetic studies have focused on canopy trees, while few studies have examined lower canopy tree species, which might differ in gene dispersal capacities. In this study, we used nuclear microsatellites (SSRs) to characterize the genetic structure of populations of Coula edulis Baill., commonly known as "African walnut", a lower canopy species exploited for its edible seeds, showing short-distance seed and pollen dispersal.

resultsAcross its distribution range, we detected one genetic cluster in Upper Guinea (UG) and six in Lower Guinea (LG). High levels of genetic differentiation (F

conclusionsOur results suggest that, given the limited gene dispersal observed in C. edulis, the observed genetic discontinuities are expected to persist over extended timescales and provide baseline information for the potential domestication of the species and the conservation of its genetic resources.