Ribosomal RNA genes in germ line and somatic cells of Ascaris lumbricoides

DNA from spermatids and 12-day-old larvae of Ascaris lumbricoides was isolated and used as a source of germ line and somatic DNA. Ribosomal RNA from Ascaris larvae with molecular weights of 0.76 × 106 for the smaller and 1.42 × 106 for the larger unit was labeled in vitro and hybridized to germ line and somatic DNA. The saturation values revealed that about 0.2% of each DNA is complementary to 18S and 28S rRNA, which is equivalent to approximately 350 and 255 ribosomal genes per haploid spermatid and larval genome, respectively.