title: Phylogenetic relationships and reticulation among Asian Elymus (Poaceae) allotetraploids: analyses of three nuclear gene trees.
abstract: This phylogenetic study focuses on a subset of the species in Elymus-specifically, the endemic Asian tetraploids presumed to combine the St genome from Pseudoroegneria with the Y genome from an unknown donor. The primary goals were to (1) determine whether the St and Y genomes are derived from phylogenetically distinct donors; (2) identify the closest relative, and potentially the likely donor, of the Y genome; and (3) interpret variation among StStYY species in terms of multiple origins and/or introgression. The goals were addressed using phylogenetic analyses of sequences from three low-copy nuclear genes: phosphoenolpyruvate carboxylase, beta-amylase, and granule-bound starch synthase I. Data sets include 16 StStYY individuals representing nine species, along with a broad sample of representatives from most of the monogenomic (i.e., non-allopolyploid) genera in the tribe. To briefly summarize the results: (1) the data clearly support an allopolyploid origin for the Asian tetraploids, involving two distinct donors; (2) the Y genome was contributed by a single donor, or multiple closely-related donors; (3) the phylogenetic position of the ElymusY genome varies among the three trees and its position is not strongly supported, so the identity of the donor remains a mystery; and (4) conflicts among the gene trees with regard to the St-genome sequences suggest introgression involving both Elymus and Pseudoroegneria.
authors.affiliation: Department of Biological Sciences, The University of Illinois at Chicago, Chicago, IL 60607, USA. robie@uic.edu
authors.forename: Roberta J
authors.initials: RJ
authors.lastname: Mason-Gamer
authors.forename: Melissa M
authors.initials: MM
authors.lastname: Burns
authors.forename: Marianna
authors.initials: M
authors.lastname: Naum
mesh_terms: D001208:Asia; D002467:Cell Nucleus / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D018745:Genome, Plant; D010730:Phosphoenolpyruvate Carboxylase / Q000235:genetics; D010802:Phylogeny; D006109:Poaceae / Q000145:classification / Q000201:enzymology / Q000235:genetics*; D011123:Polyploidy; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013214:Starch Synthase / Q000235:genetics; D001614:beta-Amylase / Q000235:genetics
chemical_list: D018744:DNA, Plant; C434607:granule-bound starch synthase I; D013214:Starch Synthase; D001614:beta-Amylase; D010730:Phosphoenolpyruvate Carboxylase