A new nuclear phylogeny of the tea family (Theaceae) unravels rapid radiations in genus Camellia

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Molecular analyses of rapidly radiating groups often reveal incongruence between gene trees. This mainly results from incomplete lineage sorting, introgression, and gene tree estimation error, which complicate the estimation of phylogenetic relationships. In this study, we reconstruct the phylogeny of Theaceae using 348 nuclear loci from 68 individuals and two outgroup taxa. Sequence data were obtained by target enrichment using the recently released Angiosperm 353 universal probe set applied to herbarium specimens. The robustness of the topologies to variation in data quality was established under a range of different filtering schemes, using both coalescent and concatenation approaches. Our results confirmed most of the previously hypothesized relationships among tribes and genera, while clarifying additional interspecific relationships within the rapidly radiating genus Camellia. We recovered a remarkably high degree of gene tree heterogeneity indicative of rapid radiation in the group and observed cytonuclear conflicts, especially within Camellia. This was especially pronounced around short branches, which we primarily associate with gene tree estimation error. Our analysis also indicates that incomplete lineage sorting (ILS) contributed to gene-tree conflicts and accounted for approximately 14 % of the explained variation, whereas inferred introgression levels were low. Our study advances the understanding of the evolution of this important plant family and provides guidance on the application of target capture methods and the evaluation of key processes that influence phylogenetic discordances.

OriginalsprogEngelsk
Artikelnummer108089
TidsskriftMolecular Phylogenetics and Evolution
Vol/bind196
Antal sider12
ISSN1055-7903
DOI
StatusUdgivet - 2024

Bibliografisk note

Funding Information:
We thank the Harvard University Herbaria and the New York Botanical Garden who generously provided the materials for the study. We thank the Bauer Core Facility of Harvard University for providing technical support during the laboratory process. We thank Lisa Pokorny, Lindsey Bechen and Elliot Gardner for offering valuable suggestions of the target enrichment lab work and Liming Cai for providing valuable advice and guidance for data analyses. The computations in this paper were run on the FASRC Odyssey cluster supported by the FAS Division of Science Research Computing Group at Harvard University. This work was supported by the Danish National Research Foundation through supporting the Center for Macroecology, Evolution and Climate [DNRF96, 2009-2019] to Yujing Yan, Rute R. da Fonseca, Carsten Rahbek, and Michael K. Borregaard; the Chinese Scholarship Council [No. 201606010394] and Harvard University Herbaria Postdoctoral Research Fellowship to Yujing Yan; setup funding from Harvard University to Charles C. Davis; and Carlsberg Young Researcher Award [CF19-0695] to Michael K. Borregaard.

Publisher Copyright:
© 2024 Elsevier Inc.

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