Because of Morgan's dramatic success with "Drosophila", many other labs throughout the world took up fruit fly genetics. Columbia became the center of an informal exchange network, through which promising mutant "Drosophila" strains were transferred from lab to lab; "Drosophila" became one of the first, and for some time the most widely used, model organisms. Morgan's group remained highly productive, but Morgan largely withdrew from doing fly work and gave his lab members considerable freedom in designing and carrying out their own experiments.