RETROTRANSPOSON-BARE-1 IS A MAJOR, DISPERSED COMPONENT OF THE BARLEY (HORDEUM-VULGARE L) GENOME

The barley BARE-1 is a transcribed, copia-like retroelement with well- conserved functional domains, an active promoter, and a copy number of at least 3 x 10(4). We examined its chromosomal localization by in si tu hybridization. The long terminal repeat (LTR) probe displayed a uni form hybridization pattern over the whole of all chromosomes, exceptin g paracentromeric regions, telomeres, and nucleolar organizer (NOR) re gions. The integrase probe showed a similar pattern. The 5'-untranslat ed leader (UTL) probe, expected to be the most rapidly evolving compon ent, labeled chromosomes in a dispersed and non-uniform manner, concen trated in the distal regions, possibly indicating a targe site prefere nce.