Some six decades ago, it had been used in the
study of human chromosomes: The chemical, which could stop mitosis in its tracks, made it easier to spy the dividing chromosomal strands in metaphase, where they could be clearly viewed
under a
light microscope.
The fruit fly Drosophila melanogaster is
studied because it is easy to grow for an animal, has various visible, heritable traits, and has a giant chromosome in its salivary glands that can be examined
under a
light microscope.