ABSTRACT
Echinoderms, particularly echinoids, have been the object of intensive analyses of genetic structure and evolutionary change. A detailed analysis of unique sequence variability within a species of the Echinodermata has been reported by Britten et al. (1978) for Strongylocentrotus purpuratus. locentrotus purpuratus in British Columbia to the population in Southern California. The differences in thermal stability between the long and short repetitive deoxyribonucleic acid (DNA) sequences of echinoderms have been reported by a number of investigators. The low thermal stability of the short repetitive DNA, after preparative reasso-ciation, indicates that the copies of these repetitive sequences in echinoderm genomes are internally diverged. Studies of interspecies repetitive sequence divergence in echinoderms indicate that the repetitive sequences have been more conservative than the total unique sequences during the evolution of species. The majority of long and short repetitive DNAs diverge at nearly equivalent rates between echinoderm species.
