Identification of a family of repeated sequences on the rye B chromosome

A novel family of highly repeated sequences on the B chromosome of rye (Secale cereale) has been identified. The D1100 family has not been detected on the rye A chromosomes and shows little or no homology to any previously described repeat sequence in rye. In addition, different rye species, and different B chromosomes within the same species, show significant heterogeneity in the arrangement of the D1100 sequences. An EcoRI clone of a member of the family has been obtained. These results provide direct evidence for the organisation and nature of the B-chromosome DNA in rye, and they are discussed in relation to the origin and evolution of rye B chromosomes.