Rubisco spacer sequence divergence in the rhodophyte alga Gracilaria verrucosa and closely related species.

In the red alga Gracilaria verrucosa, the genes encoding the large and the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) are separated by a short spacer of less than 131 bp. Sequencing of PCR-amplified Rubisco spacers from a number of populations of G. verrucosa was performed to assess the feasibility of using this sequence for discriminating among closely related species or populations. Intrapopulation comparisons of the nucleotide sequences of these spacers from five isolates of G. verrucosa, and similar species, demonstrated four main groups. The first group included isolates from Europe and Argentina while the other groups are correlated with the geographical location of their origin.