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Phylogenetic analysis of Silphium and subtribe Engelmanniinae (Asteraceae: Heliantheae) based on ITS and ETS sequence data
Author(s) -
Clevinger Jennifer A.,
Panero Jose L.
Publication year - 2000
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.2307/2656600
Subject(s) - biology , monophyly , internal transcribed spacer , phylogenetic tree , chloroplast dna , clade , molecular phylogenetics , evolutionary biology , botany , genetics , gene
The phylogenetic relationships of Silphium and subtribe Engelmanniinae were examined using DNA sequence data. The internal transcribed spacer (ITS) region and the external transcribed spacer (ETS) region were sequenced for 39 specimens representing the six genera of subtribe Engelmanniinae ( Berlandiera, Chrysogonum, Dugesia, Engelmannia, Lindheimera, and Silphium ), plus five additional genera identified as closely related to the Engelmanniinae by chloroplast DNA restriction site analysis, and three outgroups. Phylogenetic analysis supported the monophyly of Silphium with Lindheimera as sister. Silphium can be divided into two sections based upon two well‐supported clades that correspond to root type and growth form. These results also supported the expansion of subtribe Engelmanniinae to include Balsamorhiza, Borrichia, Rojasianthe, Vigethia, and Wyethia. We hypothesize that subtribe Engelmanniinae originated in Mesoamerica and later radiated to the United States. We suggest that the cypsela complex, which is present in Berlandiera, Chrysogonum, Engelmannia, and Lindheimera, arose only once and was subsequently lost in Silphium.