Positive selection and ancient duplications in the evolution of class B floral homeotic genes of orchids and grasses

• Verfasst von: Mondragón-Palomino, Mariana [VerfasserIn]
• Verfasst von: Koch, Marcus [VerfasserIn]
• Titel: Positive selection and ancient duplications in the evolution of class B floral homeotic genes of orchids and grasses
• Verf.angabe: Mariana Mondragón-Palomino, Luisa Hiese, Andrea Härter, Marcus A. Koch and Günter Theißen
• Fussnoten: Gesehen am 16.05.2017
• Titel Quelle: Enthalten in: BMC evolutionary biology
• Jahr Quelle: 2009
• Band/Heft Quelle: 9 (2009), Artikel-Nummer 81, 26 Seiten
• ISSN Quelle: 1471-2148
• DOI: doi:10.1186/1471-2148-9-81
• Datenträger: Online-Ressource
• Sprache: eng
• Reproduktion: Reproduziert als: Mondragón-Palomino, Mariana: Positive selection and ancient duplications in the evolution of class B floral homeotic genes of orchids and grasses. - London; Berlin; Heidelberg: BioMed Central; Springer, 2016. - 1 Online-Ressource (26 Seiten)
• K10plus-PPN: 1558636013

Abstract

Positive selection is recognized as the prevalence of nonsynonymous over synonymous substitutions in a gene. Models of the functional evolution of duplicated genes consider neofunctionalization as key to the retention of paralogues. For instance, duplicate transcription factors are specifically retained in plant and animal genomes and both positive selection and transcriptional divergence appear to have played a role in their diversification. However, the relative impact of these two factors has not been systematically evaluated. Class B MADS-box genes, comprising DEF-like and GLO-like genes, encode developmental transcription factors essential for establishment of perianth and male organ identity in the flowers of angiosperms. Here, we contrast the role of positive selection and the known divergence in expression patterns of genes encoding class B-like MADS-box transcription factors from monocots, with emphasis on the family Orchidaceae and the order Poales. Although in the monocots these two groups are highly diverse and have a strongly canalized floral morphology, there is no information on the role of positive selection in the evolution of their distinctive flower morphologies. Published research shows that in Poales, class B-like genes are expressed in stamens and in lodicules, the perianth organs whose identity might also be specified by class B-like genes, like the identity of the inner tepals of their lily-like relatives. In orchids, however, the number and pattern of expression of class B-like genes have greatly diverged.