Today, most scientists regard the term "mutation" as a description of a change in an individual gene, and more precisely as some minute alteration of the DNA of that gene, especially a nucleotide substitution. But the idea of mutation has changed considerably from the pre-Mendelian concepts of Darwin's generation, who viewed "fluctuating variations" as the raw material on which evolution acted, to today's up-to-the-minute genomic context of mutation...