Analysis of repeating oligonucleotide sequences in ribonucleic acids using an Apple II microcomputer

Abstract

A simple computer program has been developed to locate repeating subsequences of all possible lengths in a given nucleic acid. The observed number of repeats of subsequences was compared with the expected number of such repeats in several RNAs. The analysis showed that, in the case of rRNAs, there are no constraints in the choice of the fourth and the higher order nucleotides, while the selection is maximum at the level of nearest neighbour. This is, however, not true for RNAs coding for proteins, where the constraints are also found at the level of nucleotides containing five or more bases.