"The whole notion of the stickleback work was to get out of the mode or trap of betting on a candidate gene, and then doing a lot of work to see if you're right," notes the team's leader, Stanford University developmental biologist David M. Kingsley. Instead, he devised a top-down method that starts with the organism and the genome. This approach facilitates investigation into a central question of genetic architecture: do genes of large phenotypic effect exist, or does evolution proceed solely via micromutation, cumulative changes to multiple genes of small effect?
The question goes back to Charles Darwin, who favored continual accrual of small variations. But after him, early geneticists held that adaptation involves macromutations. Then, in the second half of the 20th century, the Modern Synthesis of Darwinism and genetics pushed the pendulum back to micromutations. However, a recent accumulation of both experimental and genetic evidence has returned ...
