Investigations of Genome Relationships Between Leymus, Psathyrostachys and Hordeum Inferred by Genomic DNA:DNA in situ Hybridization

Genome relationships between the genera Leymus Hochst., PsathyrostachysNevski and Hordeum L. (Poaceae, Triticeae) were investigatedby fluorescent in situ hybridization using both total genomicDNA and cloned DNA sequences as probes. In hybrids between speciesof Hordeum and Leymus there was a clear differentiation betweenthe H genomes of Hordeum species and the genomes of Leymus speciesafter probing with genomic Hordeum or Leymus DNA. Chromosomesof species of Leymus and Psathyrostachys were also differentiatedby subtelomeric heterochromatic segments or by negative bandsalong their length. The number and location of 18S-5·8S-26SrRNA genes varied between the investigated genera. Unusually,L. angustus and P. stoloniformis rDNA sites were localized onboth ends of some chromosomes. Interphase nuclei of the Hordeumx Leymus hybrids had groups of chromosomes from both parentalgenomes in discrete, non-intermixed domains.Copyright 1994,1999 Academic Press Taxonomy, evolution, molecular evolution, repetitive DNA, rDNA sites, in situ hybridization, Triticeae, Leymus, Hordeum, Psathyrostachys