Clustered and interspersed repetitive DNA sequence family of Chironomus. The nucleotide sequence of the Cla-elements and of various flanking sequences

J Mol Biol. 1984 Sep 5;178(1):1-15. doi: 10.1016/0022-2836(84)90227-4.


The nucleotide sequence of more than 30 cloned members of the clustered and interspersed repetitive Cla-sequence family present in the genome of various chironomids has been determined. In four cloned Cla-element clusters, the 5' and 3'-flanking sequences including the junctions between the Cla-element clusters and the flanking sequences were also sequenced. The repetitive Cla-elements, which are able to transpose under certain circumstances, have a monomer length ranging from 110 to 119 base-pairs, are very A + T-rich (greater than 80% A + T) and display numerous palindromic sequences. The Cla-elements are organized in small (4 elements) to medium-sized (greater than 30 elements) tandem repetitive clusters, which are dispersed over more than 200 sites of the chromosomes of Chironomus thummi thummi, including the non-transcribed spacer of the ribosomal DNA repeating unit. The tandem repetitive Cla-elements show anomalous behaviour during high-percentage polyacrylamide gel electrophoresis, indicating a bent or globular conformation. The flanking sequences are also repetitive, but the sequenced parts did not reveal any tandem repetitive arrangement. Near the junctions of the Cla-element clusters and the flanking sequences, short duplications are found, ranging from 5 to 12 bases, present in both sides of the Cla-element clusters. The Cla-elements might be involved in the hybrid dysgenesis phenomenon that is observed after crossings between the two subspecies Ch. th. thummi and Ch. th. piger.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autoradiography
  • Base Sequence
  • Chironomidae / genetics*
  • Chromosomes
  • Cloning, Molecular
  • DNA / genetics*
  • DNA Restriction Enzymes
  • Diptera / genetics*
  • Electrophoresis, Polyacrylamide Gel
  • Hybridization, Genetic
  • Nucleic Acid Conformation
  • Repetitive Sequences, Nucleic Acid*


  • DNA
  • DNA Restriction Enzymes