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Abstract Detail


Chatrou, Lars [1].

Deep phylogenetic incongruence in Neotropical rain forest trees (Oxandra, Annonaceae).

Phylogenetic relationships in the magnoliid plant family Annonaceae generally have been well resolved using plastid gene sequences, produced using Sanger sequencing. One of the few recalcitrant clades, with several moderately resolved nodes resulting from analysis of these data, is the Neotropical tribe Malmeeae that includes the genus Oxandra, comprising 27 species of understory to emergent trees occurring in rain forests across Central and South America. A recent taxonomic revision demonstrated a variability in leaf, flower and fruit characters among species of Oxandra that is much larger compared to other genera in the family, casting doubt on the monophyly of the genus.
We generated genome skimming data for 15 species of Oxandra and 13 species from other genera in the Malmeeae. From the sequence data we obtained alignments of ca 61,000 positions of plastid data, almost 6,000 positions of nuclear ribosomal DNA, and ca 50,000 positions of mitochondrial data.
Phylogenetic analysis of the plastid data resulted in polyphyly of Oxandra: species were placed in two clades that were not sister clades. Phylogenetic analyses of mitochondrial and nuclear data produced identical results, which differed from the analyses of plastid data, however. Mitochondrial and nuclear phylogenetic trees contained the same two clades, but in this case they were sister clades. Thus, Oxandra was retrieved as monophyletic based on mitochondrial and nuclear data. Relevant nodes in all analyses were well supported (posterior probability > 0.98). The incongruent phylogenetic pattern involves deep nodes in the phylogeny of the Malmeeae that date back to ca 10 Myr. During the presentation we will discuss possible mechanisms causing this deep incongruence, such as an ancient chloroplast capture.

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1 - Ghent University, Department of Biology, K.L. Ledeganckstraat 35, 9000, Gent, Belgium

Genome skimming
chloroplast genome
Mitochondrial genome
nuclear ribosomal DNA
Deep incongruence.

Presentation Type: Oral Paper
Session: PHYL1, Phylogenomics I
Location: San Ignacio/Starr Pass
Date: Monday, July 29th, 2019
Time: 8:00 AM
Number: PHYL1001
Abstract ID:225
Candidate for Awards:None

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