The Human Genome and Its Evolutionary Context

Our knowledge of the structure, chromosomal location, and transcription of human genes (as well as of eukaryotic genes in general) has made impressive advances in recent years, as witnessed by this Symposium. In contrast, the wider issue of genome organization has largely remained a terra incognita. Indeed, the only widely known general picture of the human genome is still based on the reassociation kinetics of short DNA fragments. This information, essentially concerning the relative amounts of sequence classes endowed with different reassociation rates and the inter-spersion pattern of repetitive and nonrepetitive DNA (Schmid and Deininger 1975), not only is very limited in itself, but also can barely be expanded any further. On the other hand, our advances regarding genes, however important otherwise, concern a minute fraction of the mammalian genome. They are, therefore, unlikely to lead to a breakthrough in our understanding of the overall organization and evolution of the...