title: Contrasting patterns of gene flow between sister plant species in the understorey of African moist forests - the case of sympatric and parapatric Marantaceae species.
abstract: Gene flow within and between species is a fundamental process shaping the evolutionary history of taxa. However, the extent of hybridization and reinforcement is little documented in the tropics. Here we explore the pattern of gene flow between three sister species from the herbaceous genus Marantochloa (Marantaceae), sympatrically distributed in the understorey of the African rainforest, using data from the chloroplast and nuclear genomes (DNA sequences and AFLP). We found highly contrasting patterns: while there was no evidence of gene flow between M. congensis and M. monophylla, species identity between M. monophylla and M. incertifolia was maintained despite considerable gene flow. We hypothesize that M. incertifolia originated from an ancient hybridization event between M. congensis and M. monophylla, considering the current absence of hybridization between the two assumed parent species, the rare presence of shared haplotypes between all three species and the high percentage of haplotypes shared by M. incertifolia with each of the two parent species. This example is contrasted with two parapatrically distributed species from the same family in the genus Haumania forming a hybrid zone restricted to the area of overlap. This work illustrates the diversity of speciation/introgression patterns that can potentially occur in the flora of tropical Africa.
authors.affiliation: Institut für Geobotanik und Botanischer Garten, University Halle-Wittenberg, Neuwerk 21, 06108 Halle, Germany; Evolutionary Biology and Ecology, CP160/12, Faculté des Sciences, Université Libre de Bruxelles, 50 Av. F. Roosevelt, B-1050 Brussels, Belgium. Electronic address: Alexandra.Ley@botanik.uni-halle.de.
authors.forename: A C
authors.initials: AC
authors.lastname: Ley
authors.affiliation: Evolutionary Biology and Ecology, CP160/12, Faculté des Sciences, Université Libre de Bruxelles, 50 Av. F. Roosevelt, B-1050 Brussels, Belgium.
authors.forename: O J
authors.initials: OJ
authors.lastname: Hardy
mesh_terms: D000349:Africa; D018744:DNA, Plant / Q000235:genetics; D065928:Forests; D051456:Gene Flow; D006239:Haplotypes; D006824:Hybridization, Genetic; D032426:Marantaceae / Q000235:genetics*; D010802:Phylogeny; D058974:Phylogeography; D017422:Sequence Analysis, DNA
chemical_list: D018744:DNA, Plant
keywords: AFLP; Chloroplast sequences; Haumania; Hybridization; Kinship coefficient; Marantochloa