Trisomy: a useful adjunct to RFLP mapping in pea

We have analysed trisomic pea plants by DNA/ DNA hybridization techniques, exploiting the copy number excess of DNA sequences in trisomics, together with a knowledge of their genetics, in order to address problems in the correlation of genetic and cytogenetic information. One such long-standing problem in pea genetics is the assignment of one rDNA locus (Rrn2) to a linkage group on chromosome 7. Our results show that Rrn2 does not reside on the same chromosome as Lg-1 or Vc-2 which we have previously shown to be linked to r, a linkage group 7 specific marker.