Cloning and sequence analysis of an extremely homogeneous tandemly repeated dima in the grasshopper eyprepocnemis plorans

Abstract

Digestion of total nuclear DNA of the grasshopper Eyprepocnemis plorans with seven different restriction endonucleases (REs), and subsequent agarose gel electrophoresis, has shown the presence of highly repetitive DNA yielding the typical ladder-like banding pattern. The most clear pattern was produced by Dral, the monomer being some 180 bp. This repeat unit was subsequently cloned and sequenced. Bidirectional sequencing of five randomly chosen clones showed exactly the same nucleotides in all 180 positions. The possible explanations for such an extreme homogeneity of this tandem repeat are discussed in the light of current hypotheses on repetitive DNA function and molecular drive mechanisms. © 1995 The Genetical Society of Great Britain.