Morphological convergence or lineage sorting? The case of Cytisus purgans auct. (Leguminosae)
Authors: Cubas, Paloma1; Pardo, Cristina1; Tahiri, Hikmat2
Source: Taxon, Volume 55, Number 3, August 2006 , pp. 695-704(10)
Publisher: International Association for Plant Taxonomy
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Abstract:
Genetic distances among populations and phylogenetic hypothesis concerning origin and diversification of Cytisus purgans s.l. are inferred by analysis of the ITS and ETS regions (nrDNA) and the trnL-trnF intergenic spacer (cpDNA). Cytisus purgans s.l., a shrub of western Mediterranean mountains, consists of two evolutionary units: C. balansae (Boiss.) Ball (Morocco, Algeria, southern Spain) and C. oromediterraneus Rivas Mart. & al. (France, Portugal, Andorra, central and northern Spain). The two units are related to different Cytisus groups, in Bayesian and Maximum Parsimony analyses, and may be genetically unrelated, their morphological similarities being the result of convergence. However, the incongruence in the position of both species in the ITS tree and the ETS and trnL-trnF trees suggests an alternative explanation. Genetic differentiation could be due to lineage sorting of allelic polymorphism in the ITS region of the common ancestor, and the morphological similarities the result of morphological parallelism. Cytisus balansae conserves ITS sequences related to old Cytisus taxa; rapid radiation may have led to a western Mediterranean lineage in which C. oromediterraneus originated.Keywords: CYTISUS PURGANS; ETS; ITS; LINEAGE SORTING; MOLECULAR PHYLOGENY; TRNL-TRNF IGS; WESTERN MEDITERRANEAN
Document Type: Research article
Affiliations: 1: Departmento de Biología Vegetal II, Facultad de Farmacia, Universidad Complutense, E-28040 Madrid, Spain 2: Département de Biologie, Faculté des Sciences, Université Mohammed V, BP1014, Rabat, Morocco
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