Chloroplast genome organisation in sugar beet and maize

The XhoI and SmaI restriction map of the chloroplast genome from the fertile cytoplasm of sugar beet has been constructed from overlapping cosmid clones. The genome was found to be typical of that of a dicotyledonous species, being 147.3 kb in size and having an inverted repeat. RbcL for the large subunit of ribulose-1,5-bisphosphate carboxylase, psbA for the 32 kD protein of the photosystem II reaction centre, and the 16S ribosomal RNA were located using heterologous probes. In both sugar beet and maize the inverted repeats recombine giving two isomeric forms of the genome.