The rediscovery of Mendel's laws a century ago launched the science that William Bateson called "genetics," and led to a new view of evolution combining selection, particulate inheritance, and the newly characterized phenomenon of "mutation." This "mutationist" view clashed with the earlier view of Darwin, and the later "Modern Synthesis," by allowing discontinuity, and by recognizing mutation (or more properly, mutation-and-altered-development) as a source of creativity, direction, and initiative. By the mid-20th century, the opposing Modern Synthesis view was a prevailing (...) orthodoxy: under its influence, "evolution" was redefined as "shifting gene frequencies," that is, the sorting out of pre-existing variation without new mutations; and the notion that mutation-and-altered-development can exert a predictable influence on the course of evolutionary change was seen as heretical. Nevertheless, mutationist ideas re-surfaced: the notion of mutational determinants of directionality emerged in molecular evolution by 1962, followed in the 1980s by an interest among evolutionary developmental biologists in a shaping or creative role of developmental propensities of variation, and more recently, a recognition by theoretical evolutionary geneticists of the importance of discontinuity and of new mutations in adaptive dynamics. The synthetic challenge presented by these innovations is to integrate mutation-and-altered-development into a new understanding of the dual causation of evolutionary change--a broader and more predictive understanding that already can lay claim to important empirical and theoretical results--and to develop a research program appropriately emphasizing the emergence of variation as a cause of propensities of evolutionary change. (shrink)

The article presents another of those ingenious mind, rebels to the yoke of religion, typical of the Italian Renaissance. Converted to Calvinism and therefore condemned to death by the Inquisition, Guglielmo Grataroli (1516-1568) became a defender of heterodox doctrine. His translation of a report of the Waldensian massacre in Calabria became part of the history of Protestant martyrs. He was the author of numerous treatises on various subjects, for which he widely used the works of Giovanni Michele Alberto da Carrara, (...) Antoine Mizauld and Gerolamo Cardano. The perfect correspondence of the topics discussed makes it probable that Giordano Bruno knew his writings. In particular, the De mutatione temporum, eiusque signis perpetuis may have inspired the De’ segni de’ tempi, a Bruno’s lost opera. This allows us to conjecture the content of the work with greater reliability. (shrink)