Lack of amplification phenomena of ribosomal RNA genes in sea urchin.

ABSTRACT

Careful quantitative analyses by spot hybridization to homologous probes demonstrate that no rDNA amplification occurs during Paracentrotus lividus oogenesis. The same approach was used to measure the copy number of the genes involved in ribosome biogenesis. Surprisingly, differently from the organisms in which the lack of rDNA amplification phenomena was observed, a very low number of constitutive rDNA repeats was found in this organism.