WAGSTAFF, STEVEN J* and ILSE BREITWIESER. Landcare Research, P.O. Box 69, Lincoln 8152, New Zealand. - Phylogenetic relationships of New Zealand Asteraceae inferred from ITS sequences.
Thirty-six new sequences including members of all New Zealand genera
of Asteraceae and 60 published sequences representing the tribal
diversity in the family were analyzed to assess the utility of ITS
sequences to resolve phylogenetic relationships. Sequence divergence
and length variation make the alignment challenging, nevertheless the
utility of ITS sequences to resolve relationships within and among
tribes of Asteraceae has been demonstrated in several recent
publications. The ITS sequences comprised conservative regions at the
3’ end of the 18S gene, the entire 5.8S gene, and the 5’ end of the
26S gene along with the intervening internal transcribed spacers. The
ITS region varied between 648 and 717 bp with a mean of 707 bp. Most
insertions or deletions were only 1-3 bp with one large deletion of 58
bp identified in the ITS-1 spacer of Brachyscome. Independent
analyses of the ITS spacer regions were largely congruent. The
presence or absence of indels gave little resolution and exhibited
high levels of homoplasy. Previous studies using chloroplast DNA
sequences and morphology provided support for several clades, yet the
relationships among some of these clades were uncertain. The combined
analysis of the entire ITS region yielded results that were largely
consistent with these earlier studies. The New Zealand species are
included in at least six clades corresponding to recognized tribes.
Our results have also clarified the tribal affinities of a few genera.
Haastia, previously aligned with the Gnaphalieae or the
Astereae, is nested in the Senecioneae. Centipeda, previously
included in the Astereae or Anthemideae, emerges near the Inuleae.
Abrotanella emerges near the base of the Senecioneae confirming
Key words: Asteraceae, ITS sequences, New Zealand, phylogeny