Macrophylogenetic analyses of the gain and loss of self-incompatibility in the Asteraceae

Department of Biology, Acadia University, Wolfville, Nova Scotia, Canada B4P 2R6.
New Phytologist (Impact Factor: 7.67). 02/2007; 173(2):401-14. DOI: 10.1111/j.1469-8137.2006.01905.x
Source: PubMed


The self-incompatibility (SI) status of 571 taxa from the Asteraceae was identified and the taxa were scored as having SI, partial SI or self-compatibility (SC) as their breeding system. A molecular phylogeny of the internal transcribed spacer (ITS) region was constructed for 211 of these taxa. Macrophylogenetic methods were used to test hypotheses concerning the ancestral state of SI in the Asteraceae, the gain and loss of SI, the irreversibility of the loss of SI and the potential for partial SI or SC to be terminal states. The ancestral breeding system in the family could not be resolved. Both maximum likelihood and parsimony analyses indicated that transitions among all breeding system states provide the best fit to the data and that neither partial SI nor SC is a terminal state. Furthermore, the data indicated that the loss of SI is not irreversible, although breeding system evolution has been more dynamic in some clades than in others. These results are discussed within the context of evidence for the gain and loss of SI, the evolutionary role of partial SI and methodological assumptions of tests of breeding system evolution.

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Available from: Sara Good, Oct 05, 2014
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    • "However, several species show a high reduction of fruit set after geitonogamous crosses and they have been considered as a self-incompatible or partially self-incompatible species [52], [61], [63]. As the Euphorbia species with reported SI belong to different subgenera and sections [31], [64], it is plausible to think that SI or partial SI could have evolved independently at several times, as has been proposed in other families [65], [66]. Similarly, the SI found in E. boetica may have evolved to avoid inbreeding depression, which is not excluded by their pre-pollination anti-selfing mechanism. "
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    • "A trait complex that might evolve even more quickly than sexually dimorphic morphological characters is courtship behaviour, which might be modified under sexual selection long before morphological adaptations take place [16-20]. While the diversifying role of sexual selection in shaping courtship behaviour has been extensively studied, the role of evolutionary constraints has gained less attention [17,21-23]. The most obvious mode of constrained evolution is irreversibility, or the fact that some traits once lost cannot be reacquired. "
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    • "20%; Xu and Qiang 2004; Weber et al. 2008) is much larger than the percentage of Asteraceae in the global flora (8.4%; Pyšek 1998). Moreover, although most tribes of Asteraceae have both self-compatible and self-incompatible taxa (Ferrer and Good-Avila 2007), a minority of Asteraceae—at least the ones with known breeding systems—are fully or partially self-compatible (36.8%; Ferrer and Good-Avila 2007), and less than half (46.0%) are capable of autonomous seed set (including autogamous and apomictic species; Fryxell 1957). "
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