Linked Life Data

10051397

Source:http://linkedlifedata.com/resource/pubmed/id/10051397

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1999-3-24
pubmed:abstractText
The 3' region of the external transcribed spacer (ETS) of 18S-26S nuclear ribosomal DNA was sequenced in 19 representatives of Calycadenia/Osmadenia and two outgroup species (Compositae) to assess its utility for phylogeny reconstruction compared to rDNA internal transcribed spacer (ITS) data. Universal primers based on plant, fungal, and animal sequences were designed to amplify the intergenic spacer (IGS) and an angiosperm primer was constructed to sequence the 3' end of the ETS in members of tribe Heliantheae. Based on these sequences, an internal ETS primer useful across Heliantheae sensu lato was designed to amplify and sequence directly the 3' ETS region in the study taxa, which were the subjects of an earlier phylogenetic investigation based on ITS sequences. Size variation in the amplified ETS region varied across taxa of Heliantheae sensu lato from approximately 350 to 700 bp, in part attributable to an approximately 200-bp tandem duplication in a common ancestor of Calycadenia/Osmadenia. Phylogenetic analysis of the 200-bp subrepeats and examination of apomorphic changes in the duplicated region demonstrate that the subrepeats in Calycadenia/Osmadenia have evolved divergently. Phylogenetic analyses of the entire amplified ETS region yielded a highly resolved strict consensus tree that is nearly identical in topology to the ITS tree, with strong bootstrap and decay support on most branches. Parsimony analyses of combined ETS and ITS data yielded a strict consensus tree that is better resolved and generally better supported than trees based on either data set analyzed separately. We calculated an approximately 1.3- to 2.4-fold higher rate of sequence evolution by nucleotide substitution in the ETS region studied than in ITS-1 + ITS-2. A similar disparity in the proportion of variable (1.3 ETS:1 ITS) and potentially informative (1.5 ETS:1 ITS) sites was observed for the ingroup. Levels of homoplasy are similar in the ETS and ITS data. We conclude that the ETS holds great promise for augmenting ITS data for phylogenetic studies of young lineages.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1055-7903
pubmed:author
pubmed:copyrightInfo
Copyright 1998 Academic Press.
pubmed:issnType
Print
pubmed:volume
10
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
449-63
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Phylogenetic utility of the external transcribed spacer (ETS) of 18S-26S rDNA: congruence of ETS and ITS trees of Calycadenia (Compositae).
pubmed:affiliation
Department of Integrative Biology, University of California, Berkeley, Berkeley, California, 94720-2465, USA. bbaldwin@uclink4.berkeley.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't