Systematics Section / ASPT
Burgess, Michael B. , Campbell, Christopher S. , Guerette, Christine .
A molecular phylogeny of Amelanchier (Rosaceae).
Amelanchier contains perhaps 25 species of the North Temperate Zone and is especially diverse and taxonomically complex in North America. We are assessing the overall phylogeny of the genus using chloroplast regions and sequences from the nuclear granule bound starch synthase I (GBSSI) gene. Outgroups are Malacomeles (two-three species from Texas to Guatemala) and Peraphyllum (one species of western United States). The only published molecular phylogeny of the genus (Mol. Biol. Evol. 14:81-90. 1997) was based on ITS sequences, the major signal from which was a clade consisting of all sampled western North American species plus two species from eastern North America, A. humilis and A. sanguinea. We refer to this group as clade A. In the present study, combined analysis of several cpDNA regions also recovers clade A except that A. sanguinea falls within a clade of eastern North American species, and A. utahensis is sister to A. asiatica. Our GBSSI tree places A. humilis and A. sanguinea with western North American species and A. asiatica with eastern North American species, not at all close to A. utahensis. These conflicts between cpDNA and nuclear trees suggest chloroplast capture, a possibility consistent with the frequent hybridization within the genus. One putative hybrid, a tetraploid from Maine, has ITS repeats identical to those of clade A and eastern North American species. GBSSI confirms the presence of a clade A parent and suggests that A. canadensis was the eastern North American parent. CpDNA sequence divergence is less than 1% within Amelanchier, and there are more potentially informative indels than substitutions. GBSSI divergence within the genus is about 2%.
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Amelanchier Systematics and Evolution
1 - University of Maine, Dept. of Biological Sciences, 5735 Hitchner Hall, Orono, ME, 04469, United States
granule bound starch synthase I
Presentation Type: Poster:Posters for Sections
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM