Plant kleptomaniacs: geographic genetic patterns in the amphi-apomicticRubusser.Glandulosi(Rosaceae) reveal complex reticulate evolution of Eurasian brambles

Abstract

AbstractRubusser.Glandulosirepresents a unique model of geographic parthenogenesis on a homoploid (4x) level. We employed double digest restriction-site associated DNA sequencing (ddRADseq) in 587 individuals of differentRubustaxa and modelling of suitable climate to characterize evolutionary and phylogeographic patterns and shed light on the geographic differentiation of apomicts and sexuals. Six ancestral species were identified that contributed to the contemporary gene pool ofR.ser.Glandulosi. While sexuals were introgressed fromR. dolichocarpusandR. moschusin West Asia and fromR. ulmifoliusagg.,R. canescensandR. incanescensin Europe, apomicts were characterized by alleles ofR.subsect.Rubus. Gene flow between sexuals and apomicts was also detected, as well as occasional hybridization with other taxa. We hypothesize that sexuals survived the last glacial period in several large southern refugia, whereas apomicts were mostly restricted to southern France from whence they quickly recolonized Central and Western Europe. The secondary contact of sexuals and apomicts was probably the principal factor that established geographic parthenogenesis inR.ser.Glandulosi. Sexual populations are not impoverished in genetic diversity along their borderline with apomicts and maladaptive population genetic processes likely did not shape the geographic patterns.HighlightsGeographic parthenogenesis inRubusser.Glandulosiis caused by secondary contactReticulate evolution in Eurasian brambles is more extensive than expectedAt least six species contributed to the evolution ofRubusser.GlandulosiExtinct ancestor’s gene pool is associated with apomixisAbstract FigureGraphical abstract