%0 Journal Article
%T Cyto-nuclear discordance in the phylogeny of Ficus section Galoglychia and host shifts in plant-pollinator associations
%A Julien P Renoult
%A Finn Kjellberg
%A Cinderella Grout
%A Sylvain Santoni
%A Boucha£¿b Khadari
%J BMC Evolutionary Biology
%D 2009
%I BioMed Central
%R 10.1186/1471-2148-9-248
%X Phylogenetic chloroplast and nuclear results demonstrated the monophyly of section Galoglychia. Within section Galoglychia, we detected several cases of statistically significant cyto-nuclear discordance. Discordances concern both terminal nodes of the phylogenetic trees and one deep node defining relationships between subsections. Because nuclear phylogeny is congruent with morphological taxonomy, discordances were caused by the chloroplast phylogeny. Introgressive hybridization was the most likely explanation for these discordances. We also detected that subsections pollinated by several wasp genera had smaller figs and were pollinated by smaller wasps than subsections pollinated by a single wasp genus.As hypothesized, we discovered evidences of past hybridization in Ficus section Galoglychia. Further, introgression was only detected in subsections presenting incongruence between plant and pollinator phylogenies and taxonomy. This supports the hypothesis that host shift is the cause for plant-pollinator incongruence. Moreover, small fig size could facilitate host shifts. Eventually, this study demonstrates that non-coding chloroplast markers are valuable to resolve deep nodes in Ficus phylogeny.Frequent natural hybridization events in vascular plants were documented by early biologists (e.g. [1,2]). However, the prevalence of hybridization events is unevenly distributed across the plant phylogeny and seems to be concentrated within a small fraction of families and genera [3]. Grant [4] pointed out that the frequency of natural hybridizations varies with factors such as life history, breeding system, environmental disturbance, genetic predisposition, and eventually pollination syndrome. In this context, plant species pollinated by specific pollinator species are predicted to present almost no hybridization events. Indeed, in specific mutualisms as plant-pollinator associations, the associated species usually present co-adaptations involved in attraction, recognitio
%U http://www.biomedcentral.com/1471-2148/9/248