Systematics/Phytogeography / Taxonomie/ Section
Li, Jianhua , Frank, Margaret , Chen, Yousheng .
Maple Phylogenetics Inferred from Sequences of Nuclear and Chloroplast Genomes.
The genus Acer (maple) consists of approximately 130 species making it one of the most species-rich tree genera in the Northern Hemisphere. Maples are easily recognized by their opposite leaf arrangement and samara type fruit. While the modern center of diversity is in central and southwestern China with two-thirds of the total number of species, some morphologically distinctive lineages occur in Japan, North America, Central Asia, Europe, and Indonesia. Recent phylogenetic studies of Acer have used sequences of nuclear ribosomal (nr) and chloroplast (cp) DNA regions. However, all had a limited taxon sampling and deep relationships among sections were poorly resolved. Although nucleotide sequences of many Acer species are available in the GenBank, species identity needs verification before their sequences can be used in phylogenetic analyses because the taxonomy of Acer is notoriously confusing and voucher specimens are not readily available. We used the cp psbA-trnH region to help verify species identification. Our results raise concerns about species identity of some Acer species in the GenBank (e.g., Acer wardii) and lead us to suggest that a barcoding sequence be required when researchers submit their sequences of interest. We also analyzed a large data set containing over 90 species of Acer and three markers (nrDNA ITS region and cp ndhF gene and non-coding trnL-trnF regions) to test the monophyly of sections. Both nuclear and cp sequences support previously recognized sections and further suggest that Acer caesium and A. yangbiense form a new section. To infer relationships among sections we then increased the number of DNA regions to eight (two nuclear and six cp) for a data set of 47 taxa representing outgroup and one to three species of individual sections. Intersectional relationships obtained using cp and nuclear genes differ significantly, indicating a complex evolutionary history of Acer at the molecular level.
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1 - Harvard University, Arnold Arboretum, Harvard University Herbaria, 22 Divinity Avenue, Cambridge, Massachusetts, 02138, USA
2 - Harvard University, Arnold Arboretum, 22 Divinity Avenue, Cambridge, MA, 02138, United States
3 - Chinese Academy of Sciences, Institute of Botany, 20 Nanxincun, Xiangshan, Beijing, 100093, China
nuclear and chloroplast DNA analysis
Presentation Type: Poster:Posters for Sections
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM