DNA structure of the B chromosome of rye revealed by in situ hybridization using repetitive sequences

Abstract

To clarify the DNA structure of the B chromosome of rye, Secale cereale L. we carried out in situ hybridization using probes of two highly repetitive sequences (pSc74 ami pScll9) of rye A chromosome, of total genomic DNA* from plants with (4 B) or without (0 B) B chromosomes, ami probes of fractionated genomic DNA (1.14-kb and 1.28-kb sequences) from a 4 B plant. Clones pSc74 and pScll9 did not hybridize to the B chromosomes except at small interstitial sites. A probe consisting of the total DNA of a 0 B plant hybridized over the entire length of all the A and B chromosomes except for the telomeric C-band region of the long arm of the B chromosome. A probe of total DNA from a 4 B plant produced signals only in the terminal C-band region after prehybridization with the 0 B plant DNA. A probe consisting of Dra I -digested 1.14-kb fragments from a 4 B plant hybridized to the telomeric region of the B chromosome. © 1992, The Genetics Society of Japan. All rights reserved.