title: Molecular cloning and sequence analysis of highly repetitive DNA sequences contained in the eliminated genome of Ascaris lumbricoides.
abstract: High molecular weight DNA from germ line and somatic cells of the DNA eliminating nematode Ascaris lumbricoides has has been isolated and digested with different restriction enzymes. The resulting DNA fragments were separated by agarose gel electrophoresis. Germ line but not somatic DNA shows a prominent band about 120 bp long as well as multiples of that length. These fragments are shown to be monomers and multimers of a highly repetitive satellite DNA, which is eliminated mostly but not completely during the process of chromatin diminution. Restriction digests, hybridization experiments and sequence analysis revealed that this eliminated satellite is composed of a whole set of different but related variant classes, all of them showing the same repeating unit length of about 120 bp. Members of the same variant class are tandemly linked and therefore physically separated from other variant classes. All satellite sequences can be derived from the same common ancestor sequence, differing only by base substitutions, insertions and deletions. There is no evidence for transcription of satellite DNA at any stage and tissues analyzed.
mesh_terms: D000818:Animals; D001200:Ascaris / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D004262:DNA Restriction Enzymes; D004276:DNA, Satellite / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D014158:Transcription, Genetic
chemical_list: D004276:DNA, Satellite; D004247:DNA; D004262:DNA Restriction Enzymes