Another week and another mystery biologist. In keeping with my current theme, this is related to a technique or tool that is invaluable to the regular biologist (although this one depends very much on your field and is becoming replaced by other techniques).
As for last week, it was Hermann J Muller - one of the pioneers of Drosophila research and the mutagenic effects of radiation. The main reason I covered him though was for discovering balancer chromosomes - chromosomes with multiple inversions that are incapable of recombining with their sister chromosome. As someone who has worked with flies for a decade you have no idea how much easier this set of tools has made my life (and that includes you TM2 with your Ultrabirothax phenotype!)