CLONING AND SEQUENCE-ANALYSIS OF AN EXTREMELY HOMOGENEOUS TANDEMLY REPEATED DNA IN THE GRASSHOPPER EYPREPOCNEMIS-PLORANS

Digestion of total nuclear DNA of the grasshopper Eyprepocnemis ploran s with seven different restriction endonucleases (REs), and subsequent agarose gel electrophoresis, has shown the presence of highly repetit ive DNA yielding the typical ladder-like banding pattern. The most cle ar pattern was produced by DraI, the monomer being some 180 bp. This r epeat unit was subsequently cloned and sequenced. Bidirectional sequen cing of five randomly chosen clones showed exactly the same nucleotide s in all 180 positions. The possible explanations for such an extreme homogeneity of this tandem repeat are discussed in the light of curren t hypotheses on repetitive DNA function and molecular drive mechanisms .