Phylogenetic relationships and Y genome origin in Elymus L. sensu lato (Triticeae; Poaceae) based on single-copy nuclear Acc1 and Pgk1 gene sequences

Phylogenetic analysis of Elymus (Poaceae) in western China

“…In addition, studies on the single copy nuclear β-amylase gene (Mason-Gamer et al, 2005), DNA polymerase subunit II (RPB2) sequences (Sun et al, 2008), and elongation factor G (EF-G) sequence data (Yan et al, 2011) have suggested that the Elymus Y-genome originated in an independent Y diploid species that is now extinct or undiscovered. However, Fan et al (2013) suggested that the Elymus Y-genome is closely related to the Peridictyon sanctum (Xp -genome) based on single-copy nuclear acetyl-coa carboxylase-1 (Acc1) and phosphoglycerate kinase -1 (Pgk1) gene sequences. Therefore, the accumulated evidence suggests that the Elymus Y-genome originated in a different species or in multiple species.…”

“…Additionally, some studies (Helfgott and Mason-Gamer, 2004;Mason-Gamer, 2013) showed that North American Hordeum species were the diploid progenitors of the North American and Eurasian Elymus species. Other studies (Sun and Komatsuda, 2010;Fan et al, 2013) showed that the Hordeum H-genome from western China may have been a donor to Elymus, such as Hordeum bogdanii.…”

“…Early studies examined hypotheses of phylogenetic relationships based on cytological data (Lu and Salömon, 1992). Subsequently, researchers focused on determining the origin of the Y-genome; currently, there are different views regarding the diploid donor of the Y-genome based on which molecular makers or whether the same Elymus species are sampled (Liu et al, 2006;Yan et al, 2011;Fan et al, 2013). Few molecular phylogenetic studies have included samples of Elymus species from western China.…”

Flowering Plants. Monocots

“…Discrepancies between phylogenies produced by nuclear and chloroplast genes are increasingly demonstrating reticulation. In addition, single copy nuclear genes are clearly effective in resolving complex reticulate phylogenies (see, for example, studies on Elymus;Fan et al 2013;Hu et al 2013;, 2010a, 2010b, and these will need to be applied to problems throughout the subfamily. Several large polyploid genera appear to be polyphyletic (e.g., "Calamagrostis"; Saarela et al 2010); the morphological characters associated with such genera are clearly homoplasious, creating difficulties with diagnosis.…”

VI. Subfamily Pooideae Benth. (1861)

“…Discrepancies between phylogenies produced by nuclear and chloroplast genes are increasingly demonstrating reticulation. In addition, single copy nuclear genes are clearly effective in resolving complex reticulate phylogenies (see, for example, studies on Elymus;Fan et al 2013;Hu et al 2013;Mason-Gamer et al 2002, 2010a, 2010b, and these will need to be applied to problems throughout the subfamily. Several large polyploid genera appear to be polyphyletic (e.g., "Calamagrostis"; Saarela et al 2010); the morphological characters associated with such genera are clearly homoplasious, creating difficulties with diagnosis.…”