A prevalent persistent global nonrandomness that distinguishes coding and non-coding eucaryotic nuclear DNA sequences.

Coding sequences of eucaryotic nuclear DNA were characterized by an excess of short runs and a deficit of long runs of weak and of strong hydrogen bounding bases; non-coding sequences by a deficit of short runs and an excess of long runs, in the same of purines and of pyrimidines. The conservation of these attributes across DNA sequences coding for proteins of widely different function, across widely different eucaryotic species for the same protein and across related genes that diverged a long time ago and that now show large differences in base and, if coding, amino acid sequence suggested that these attributes have survival value. It was concluded that these attributes constitute probalistic constraints on the primary structure (base sequence) of both coding and non-coding DNA.