Evolutionary importance of gene regulation

To assess the relative importance of regulatory mutations and structural gene mutations in adaptive evolution at the organismal level, two kinds of evidence were considered: 1) Evidence concerning the mechanism by which bacterial populations acquire genetically the ability to utilise a novel carbon source. (2) Evidence from studies of rates of evolutionary change in structural genes, number of chromosomes, number of chromosomal arms, hybrid in viability and anatomy of vertebrates. It is concluded tentatively that evolution at the organismal level depends chiefly on regulatory mutations and that gene rearrangement is an important mechanism for achieving altered patterns of gene regulation.ALLAN C. WILSON, Department of Biochemistry, University of California, Berkeley, California