Repeated evolution of dioecy from androdioecy in Acer

• Published in: The New phytologist 2005-02, Vol.165 (2), p.633-640
• Main Authors: Gleiser, Gabriela, Verdú, Miguel
• Format: Article
• Language: English
• Subjects: Acer; Acer - genetics; Androdioecy; Biological and medical sciences; Biological Evolution; Biological taxonomies; Biology and morphogenesis of the reproductive apparatus. Photoperiodism, vernalisation; Breeding; comparative method; dichogamous subdioecy; Dioecy; duodichogamous monoecy; Evolution; evolution of dioecy; evolutionary trends; forest trees; Fundamental and applied biological sciences. Psychology; heterodichogamous androdioecy; heterodichogamous trioecy; heterodichogamy; inbreeding; Male animals; Monoecy; Phylogenetics; Phylogeny; Plant cytology, morphology, systematics, chorology and evolution; Plant evolution; Plant physiology and development; Reproduction; sexual specialization; speciation; Vegetative and sexual reproduction, floral biology, fructification
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.2004.01242.x

• The evolution of breeding systems was studied in the genus Acer, with special attention to the origin of androdioecy and dioecy, using a phylogenetic approach. • Parsimony and maximum-likelihood techniques were used to infer the ancestral character state and trends in the evolution of breeding systems. Information on breeding systems was obtained from the literature, and phylogenetic relationships were taken from three published phylogenies. • Although a general trend from duodichogamy to dioecy through heterodichogamy has been proposed for the geneus Acer, our results show that a general trend is not detected when phylogenetic relationships are taken into account. Dioecy appeared as a derived state that evolved at least three times and never reversed towards other states. • Three different paths to dioecy have been followed in the genus Acer: from heterodichogamous androdioecy; from heterodichogamous trioecy; and from dichogamous subdioecy. Therefore, although the best documented cases of evolution of androdioecy indicate that this breeding system evolves from dioecy, in the genus Acer the opposite situation occurs (androdioecy leading to dioecy). Here we discuss the role of inbreeding avoidance and sexual specialization as selective forces driving the evolution of dioecy in the genus Acer.