Systematics Section / ASPT
Ambrose Michael, Karen , Alice, Lawrence .
Nuclear GBSSI sequences demonstrate a hybrid origin of 8x Rubus chamaemorus (Rosaceae).
OUR goal was to assess the origin of the circumboreal octoploid (x = 7) species Rubus chamaemorus (cloudberry) and clarify basal relationships in Rubus. We used DNA sequences of three chloroplast regions (rpl16 intron, trnK intron, trnL-trnF), nuclear ribosomal internal transcribed spacers, and the nuclear granule-bound starch synthase (GBSSI-1) gene. Analyses of ITS and cpDNA data indicate that R. chamaemorus is one of eight basal species representing three subgenera that occurs outside a large, well-supported clade (named ‘A’ for reference). Moreover, no nucleotide site polymorphism has been detected in ITS. Parsimony and maximum likelihood analyses of GBSSI-1 sequences demonstrate that three different alleles are present in R. chamaemorus; one occurs outside clade A (sister to R. lasiococcus) among basal Rubus species and the other two alleles nest within clade A (sister to R. arcticus). Both putative parental species have a prostrate habit, simple to trifoliate leaves, northern geographic distributions, and lack stem armature. Thus, these data suggest that R. chamaemorus may be an ancient allopolyploid. The addition of GBSSI-1 data to cpDNA and ITS do not substantially improve resolution among the basal species, though New World subg. Anoplobatus species form a monophyletic group. Further, the phylogenetic position of Dalibarda repens relative to Rubus remains elusive.
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1 - Western Kentucky University, Biology, 1906 College Heights Blvd., Bowling Green, Kentucky, 42101-1080, USA
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM