Journal
MOLECULAR PHYLOGENETICS AND EVOLUTION
Volume 33, Issue 2, Pages 289-299Publisher
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.ympev.2004.05.012
Keywords
Hordetan; internal transcribed spacer; phylogenetic analysis; rapid radiation; rDNA evolution
Ask authors/readers for more resources
Hordeum (Poaceae, Triticeae) occurs with 31 species worldwide in temperate regions, with the exception of Australasia. About 50% of the species are polyploids (4x, 6x) or occur as di- and polyploid forms. To analyze the phylogenetic relationships among diploid and polyploid taxa of the genus the nuclear rDNA internal transcribed spacer region (ITS) was analyzed for 91 accessions, representing all Hordeum species, together with 10 outgroup species. PCR products were either directly sequenced (outgroups) or cloned and eight clones per individual were analyzed. Phylogenetic analysis revealed four major clades that concur with the four genome groups in Hordeum (H,I, X-a, and X-u). Allopolyploids, putative autopolyploids, and species groups within the closely related H-genome clade could be identified. The ITS data indicate times of independent evolution of paralogous rDNA clusters on different chromosomes intermitted by sweeps of homogenization among these clusters and bi-directional homogenization of the clusters in diploids. Penalized likelihood analysis revealed an age of about 12 million years (my) for the genus and indicated the start of a rapid radiation in the H-genome group about 2.5 my ago in South America and Asia. (C) 2004 Elsevier Inc. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available