HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (17) Citing Articles via Google Scholar Google Scholar Articles by Morrell, PeterL. Articles by Rieseberg, LorenH. Search for Related Content PubMed Articles by Morrell, PeterL. Articles by Rieseberg, LorenH. Agricola Articles by Morrell, PeterL. Articles by Rieseberg, LorenH.

Molecular tests of the proposed diploid hybrid originof Gilia achilleifolia (Polemoniaceae)¹

^a Rancho Santa Ana Botanic Garden, 1500 NorthCollege Avenue, Claremont, California 91711-3157 ^b Department of Biology, Indiana University,Bloomington, Indiana 47405-6801

Gilia achilleifolia is a putative diploid hybrid species. Hybrid origin was hypothesized based on traditional biosystematicevidence (i.e., morphological, cytological, and crossability data),which may be insufficient to establish genealogical history. Here,phylogenetic analysis of sequence data from the internal transcribedspacer (ITS) regions is used to examine the relationship between theputative hybrid species and its proposed parents. Isozyme variation isassayed to test for genetic additivity in the putative hybrid taxon andmorphological data are analyzed cladistically to evaluate the charactersthat led to the original hypothesis of hybrid origin. The ITS-basedgene tree placed G. achilleifolia in two divergent clades, eachsister to one of the putative parental lineages. Little isozymeadditivity was observed and G. achilleifolia possessed sixunique alleles among 42 alleles observed. However, ITS and isozymetrees differed in their placement of the two lineages of G.achilleifolia; both lineages are closer to a third putative parentin the isozyme tree. Also, G. achilleifolia is intermediate orpolymorphic for all nine morphological characteristics differentiatingthe parental species. Sorting of ancestral polymorphisms cannot easilyaccount for expression patterns of seven of these characters. In ourview, these results fail to distinguish between alternative hypothesesof ancient hybrid origin and divergent evolution, belying the difficultyof detecting ancient hybrids.

Key Words: geneticadditivity • hybridspeciation • isozymes • ITS (InternalTranscribedSpacer) • morphology • recombinationalspeciation • trnL

This article has been cited by other articles:

				D. H. Goldman, R. K. Jansen, C. van den Berg, I. J. Leitch, M. F. Fay, and M. W. Chase Molecular and cytological examination of Calopogon (Orchidaceae, Epidendroideae): circumscription, phylogeny, polyploidy, and possible hybrid speciation Am. J. Botany, May 1, 2004; 91(5): 707 - 723. [Abstract] [Full Text] [PDF]