TY - JOUR
T1 - Evolution of syncarpy and other morphological characters in African Annonaceae
T2 - A posterior mapping approach
AU - Couvreur, T. L.P.
AU - Richardson, J. E.
AU - Sosef, M. S.M.
AU - Erkens, R. H.J.
AU - Chatrou, L. W.
N1 - Funding Information:
We thank Thierry Deroin and Timo van der Niet for useful comments on a previous version of the manuscript. Two anonymous reviewers have also provided very constructive comments significantly improving an earlier version of the manuscript. The National Geographic Society is also thanked for funding a field trip to Gabon for TLPC and SMSM in 2005. Finally, Ann Robertson, David Johnson and the Missouri Botanical Gardens in St. Louis are deeply thank for providing good quality DNA material for some of the African species.
Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2008/4
Y1 - 2008/4
N2 - The congenital fusion of carpels, or syncarpy, is considered a key innovation as it is found in more than 80% of angiosperms. Within the magnoliids however, syncarpy has rarely evolved. Two alternative evolutionary origins of syncarpy were suggested in order to explain the evolution of this feature: multiplication of a single carpel vs. fusion of a moderate number of carpels. The magnoliid family Annonaceae provides an ideal situation to test these hypotheses as two African genera, Isolona and Monodora, are syncarpous in an otherwise apocarpous family with multicarpellate and unicarpellate genera. In addition to syncarpy, the evolution of six other morphological characters was studied. Well-supported phylogenetic relationships of African Annonaceae and in particular those of Isolona and Monodora were reconstructed. Six plastid regions were sequenced and analyzed using maximum parsimony and Bayesian inference methods. The Bayesian posterior mapping approach to study character evolution was used as it accounts for both mapping and phylogenetic uncertainty, and also allows multiple state changes along the branches. Our phylogenetic analyses recovered a fully resolved clade comprising twelve genera endemic to Africa, including Isolona and Monodora, which was nested within the so-called long-branch clade. This is the largest and most species-rich clade of African genera identified to date within Annonaceae. The two syncarpous genera were inferred with maximum support to be sister to a clade characterized by genera with multicarpellate apocarpous gynoecia, supporting the hypothesis that syncarpy arose by fusion of a moderate number of carpels. This hypothesis was also favoured when studying the floral anatomy of both genera. Annonaceae provide the only case of a clear evolution of syncarpy within an otherwise apocarpous magnoliid family. The results presented here offer a better understanding of the evolution of syncarpy in Annonaceae and within angiosperms in general.
AB - The congenital fusion of carpels, or syncarpy, is considered a key innovation as it is found in more than 80% of angiosperms. Within the magnoliids however, syncarpy has rarely evolved. Two alternative evolutionary origins of syncarpy were suggested in order to explain the evolution of this feature: multiplication of a single carpel vs. fusion of a moderate number of carpels. The magnoliid family Annonaceae provides an ideal situation to test these hypotheses as two African genera, Isolona and Monodora, are syncarpous in an otherwise apocarpous family with multicarpellate and unicarpellate genera. In addition to syncarpy, the evolution of six other morphological characters was studied. Well-supported phylogenetic relationships of African Annonaceae and in particular those of Isolona and Monodora were reconstructed. Six plastid regions were sequenced and analyzed using maximum parsimony and Bayesian inference methods. The Bayesian posterior mapping approach to study character evolution was used as it accounts for both mapping and phylogenetic uncertainty, and also allows multiple state changes along the branches. Our phylogenetic analyses recovered a fully resolved clade comprising twelve genera endemic to Africa, including Isolona and Monodora, which was nested within the so-called long-branch clade. This is the largest and most species-rich clade of African genera identified to date within Annonaceae. The two syncarpous genera were inferred with maximum support to be sister to a clade characterized by genera with multicarpellate apocarpous gynoecia, supporting the hypothesis that syncarpy arose by fusion of a moderate number of carpels. This hypothesis was also favoured when studying the floral anatomy of both genera. Annonaceae provide the only case of a clear evolution of syncarpy within an otherwise apocarpous magnoliid family. The results presented here offer a better understanding of the evolution of syncarpy in Annonaceae and within angiosperms in general.
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U2 - 10.1016/j.ympev.2008.01.018
DO - 10.1016/j.ympev.2008.01.018
M3 - Research Article
C2 - 18343689
AN - SCOPUS:41149098480
SN - 1055-7903
VL - 47
SP - 302
EP - 318
JO - Molecular Phylogenetics and Evolution
JF - Molecular Phylogenetics and Evolution
IS - 1
ER -