Repetitive and Non-Repetitive DNA Sequences and a Speculation on the Origins of Evolutionary Novelty

Recent experimental information on DNA sequence repetition is reviewed, and the significance of both repetitive and non-repetitive sequence considered. Included are a summary of data on the distribution of genome sizes in animals, new experiments on interspecific DNA homology, the distribution of sequence frequencies, and the interspersion of repetitive sequences within the genome. Aspects of the process of evolution are considered at the level of change in the DNA. the process by which novel structure and function could have arisen during evolution are considered speculatively in terms of the authors' gene regulation theory (Britten and Davidson, 1969).