Variation in highly repetitive DNA composition in rye and wild relatives discovered by FISH

Abstract

Determination of the sequence organization of the chromosomes terminal regions in Secale cereale L. varieties and some of its wild relatives for further identification of indivi dual chromosomes with the use of appropriate probes. Methods. Fluorescence in situ hybridization, microscopy. Results. FISH analysis revealed 26-28 sites of the pSc200 sequence at the ends of all 14 pairs of chromosomes and 18 signals of the pSc250 sequence on the chromosomes of S. cereale in four accessions. Repeats were differently localized on the chromosomes of the closely related species Dasypyrum villosum and Dasypyrum breviaristatum, so it can be as sumed that the tetraploid D. breviaristatum has an allopolyploid origin, may not be a descen dant of D. villosum. Conclusions. A characteristic distribution of pSc200 and pSc250 tandem repeats of the tribe Triticeae was established, which allows revealing the evolutionary relation ships between the studied species and the directions of their divergence.