Transduction and Skeletal Evolution

Abstract

IT has been suggested^1,2 that transduction of genes by viruses was an important mechanism in evolution for spreading useful mutations between organisms not formally related. I suggest that this may be an essential part of the explanation of one of the most remarkable features of the palaeontological record, the relatively sudden and almost simultaneous appearance in the Cambrian sedimentary deposits of fossils, consisting of the mineral skeletons of animals belonging to many different phyla of the animal kingdom. If, as we must assume, these animals are the products of divergent evolution from a common set of ancestors, the time needed for such divergence is probably to be reckoned in hundreds of millions of years. The scanty but growing record of Pre-Cambrian fossils seems to show, however, that all these animals with skeletons evolved from soft-bodied ancestors during 100 m.y. at most. This parallel and rapid evolution seems to demand a mechanism beyond the accepted processes of spontaneous mutation and natural selection.