Ribosomal rna genes and supernumerary b chromosomes of rye

Abstract

The presence of ribosomal RNA genes on rye supernumerary B chromosomes from three different rye populations has been investigated by ribosomal RNA/DNA hybridisation. DNAs were purified from wheat plants containing zero, two, three or four rye B chromosomes and from individual plants from two rye populations containing different numbers of B chromosomes. The number of ribosomal RNA genes was highly correlated with rye B chromosome number in the wheat plants but not in the rye plants. It is suggested, therefore, that not all rye B chromosomes are the same and that those transferred into the wheat genetic background each carry approximately 650 ribosomal RNA genes. © 1975 The Genetical Society of Great Britain.