the main clusters of ribosomal genes , or nucleolus organizers , have been located by in situ nucleic acid hybridization of xenopus laevis 3h labelled ribosomal rna to mitotic chromosomes in squash preparations of intestinal epithelium from 7 species of plethodon and 3 species of aneides .
C0035553
ribosomal
C0035701
ribosomal