GENOME AND CHROMOSOME IDENTIFICATION IN CULTIVATED BARLEY AND RELATEDSPECIES OF THE TRITICEAE (POACEAE) BY IN-SITU HYBRIDIZATION WITH THE GAA-SATELLITE SEQUENCE

The satellite sequence studied was primarily composed of GAA repeats o rganized in long tracts of heterochromatic DNA. Fluorescent in situ hy bridization (FISH) with the GAA satellite (GAA banding) to the chromos omes of barley, wheat, rye, and other Triticeae species produced bandi ng patterns similar to those obtained by N-banding. The GAA-banding pa tterns of barley are described in detail and those of 12 other Tritice ae species are described briefly. In situ hybridization with the GAA-s atellite sequence permits identification of all the chromosomes of bar ley. It is a valuable alternative to other banding techniques, especia lly in connection with physical gene mapping by FISH. The application of the GAA-satellite sequence for the characterization of genomes in p hylogenetic studies of genera containing the sequence is discussed.