Abridged 5S rDNA units in sea beet (Beta vulgarissubsp.maritima)

Abstract

Amplification by polymerase chain reaction of the 5S rDNA repeat units of Beta vulgaris subsp. maritima resulted in a 350-bp product corresponding to the full-length 5S unit, but also revealed 4 abridged unit classes, each with a deletion that removed most of the spacer and 12–76 bp of the coding sequence. Each abridged type lacks at least 1 of the conserved elements involved in transcription of the 5S gene, and so appear to be nonfunctional. Network analysis revealed that the abridged units are evolving in the same manner as the full-length versions.Key words: 5S rDNA, Beta vulgaris subsp. maritima, network analysis, sea beet.