Molecular phylogeny of the genus Hordeum using three chloroplast DNA sequences.

The genus Hordeum consists of three cytotypes (2x, 4x, and 6x). Its reproductive isolation has been incomplete between closely related species and hence the genetic relationship is reticulate and complex. We used 32 taxa of Hordeum and three chloroplast DNA sequences, matK, atpB-rbcL, and trnL-trnF in the current study. Molecular phylogenetic analysis based on sequence data of the three chloroplast DNA regions clearly demonstrated genetic relationships among taxa and origin of polypoids. The formation of H. secalinum likely involved hybridization between Hordeum marinum subsp. marinum and a Eurasian diploid possessing the H genome. The formation of hexaploid Hordeum brachyantherum involved hybridization between tetraploid H. brachyantherum and diploid H. marinum subsp. gussoneanum. The formation of three tetraploids, H. brachyantherum, Hordeum jubatum, and Hordeum guatemalense, probably involved hybridization between H. brachyantherum subsp. californicum and an altered H genome diploid. The formation of Hordeum arizonicum involved the two taxa Hordeum pusillum and H. jubatum.

[1]  R. Bothmer,et al.  Meiosis in interspecific Hordeum hybrids. I. Diploid combinations , 1986 .

[2]  J. Felsenstein.  CONFIDENCE LIMITS ON PHYLOGENIES: AN APPROACH USING THE BOOTSTRAP , 1985, Evolution; international journal of organic evolution.

[3]  J. Thompson,et al.  The CLUSTAL_X windows interface: flexible strategies for multiple sequence alignment aided by quality analysis tools. , 1997, Nucleic acids research.

[4]  R. Jørgensen,et al.  Variation and differentiation in Hordeum marinum (Poaceae) , 1989 .

[5]  I. Linde-Laursen,et al.  An ecogeographical study of the genus Hordeum. 2nd edition , 1995 .

[6]  C. Pedersen,et al.  Phylogenetic analysis of the genus Hordeum using repetitive DNA sequences , 1994, Theoretical and Applied Genetics.

[7]  M. Kimura.  Estimation of evolutionary distances between homologous nucleotide sequences. , 1981, Proceedings of the National Academy of Sciences of the United States of America.

[8]  Ando,et al.  Detection of Hordeum marinum genome in three polyploid Hordeum species and cytotypes by genomic in situ hybridization , 2004, Hereditas.

[9]  D. Swofford.  PAUP*: Phylogenetic analysis using parsimony (*and other methods), Version 4.0b10 , 2002 .

[10]  A taxonomic study of the annual Hordeum depressum and related species , 1988 .

[11]  B. Baum,et al.  Relationships among native and introduced North American species of Hordeum, based on chloroplast DNA restriction-site variation , 1991 .

[12]  G. Covas.  TAXONOMIC OBSERVATIONS ON THE NORTH AMERICAN SPECIES OF HORDEUM , 1949 .

[13]  R. Bothmer,et al.  Meiosis in interspecific Hordeum hybrids. IV. Tetraploid (4x × 4x) hybrids , 1988 .

[14]  S. Sakamoto.  INTERGENERIC HYBRIDIZATION AMONG THREE SPECIES OF HETERANTHELIUM, EREMOPYRUM AND HORDEUM, AND ITS SIGNIFICANCE FOR THE GENETIC RELATIONSHIPS WITHIN THE TRIBE TRITICEAE* , 1974 .

[15]  J. W. Morrison,et al.  CYTOGENETIC STUDIES IN THE GENUS HORDEUM. V. H. JUBATUM AND THE NEW WORLD SPECIES , 1961 .

[16]  K. Tanno,et al.  Phylogeny in the genus Hordeum based on nucleotide sequences closely linked to the vrs1 locus (row number of spikelets). , 1999, Genome.

[17]  J. Doebley,et al.  CHLOROPLAST DNA VARIATION AND THE PHYLOGENY OF HORDEUM (POACEAE) , 1992 .