Parsimony analyses were conducted for 46 genera representing all subfamilies
and tribes within Proteaceae using two chloroplast sequences: the gene
atpB and the noncoding spacer region between
atpB and rbcL. The spacer region
was more variable than atpB and provided insertion and
deletion data as well as nucleotide substitutions. The
atpB and spacer region data sets were highly congruent
(as indicated by the partition homogeneity test) and were analysed separately
and combined. Both unweighted and weighted character states (3 : 1 correction
for transition bias) for the atpB data resulted in very
similar strict consensus trees. In addition, the large subfamilies Proteoideae
and Grevilleoideae were analysed separately, using appropriate outgroups
determined by the analyses with complete sampling. The results from the
combination of data were better resolved and supported than the results from
each separate data set, although the Grevilleoideae were highly unresolved in
all analyses. Most subfamilies in the Proteaceae were essentially
monophyletic, but most tribes and subtribes were not.
Bellendena is weakly supported as the sister group to
all remaining members of the Proteaceae. Monotypic Eidotheoideae is well
supported as a member of Proteoideae. Carnarvonioideae and Sphalmioideae are
strongly supported as closely allied to the Grevilleoideae, but their
positions in relation to this subfamily are unresolved. Other unusual
alliances supported by our molecular data are:
Isopogon–Adenanthos–Leucadendron–Protea,
Petrophile–Aulax,
Cardwellia–Euplassa–Gevuina,
and
Opisthiolepis–Buckinghamia–Grevillea.
The tree resulting from the combined data showed limited congruence with
morphological characters (flower pairs, stylar pollen presentation, and ovule
number). Congruence with chromosome number was minimal, but our tree does
support previous hypotheses of multiple aneuploidy and chromosome doubling
events. The African and South American genera included in our analysis are
dispersed among various clades with taxa from Australia and Asia, suggesting a
former Gondwanian distribution for Proteaceae.
A PCR-based DNA amplification method was applied to genetically distinguish the popular dietary supplement Hypericum perforatum L. (common St. John's Wort) from other related Hypericum species. Nuclear ribosomal gene sequences of the internal transcribed spacer (ITS) region were analyzed for 50 Hypericum taxa native to the Old and New Worlds, representing 11 of the 36 currently accepted taxonomic sections. This study provides a genetic method for authentication of commercial H. perforatum preparations. In addition, these data allow a preliminary assessment of phylogenetic relationships within the genus, revealing three strongly supported monophyletic clades, plus several secondary monophyletic groupings. Using ITS gene sequences, we were able to distinguish H. perforatum from all other species of Hypericum included in this study.
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