Franz Moewus is perhaps remembered more often for scrutiny of his scientific veracity, rather than his pioneering work on the genetics and reproductive cycle of the single-celled algae Chlamydomonas. Chlamydomonas has a complex life cycle, having both asexual and sexual phases. Moewus claimed that copulation only occurred between male and female types, and that sexual reproduction furthermore depended on the presence of certain chemical factors. This early work lead Moewus to path-breaking research in the late 1930s on the genetic control of biochemical pathways. This work was similar in concept to, and was published a year before, the one-gene, one-enzyme theory of the American geneticists George Beadle (1903-1989) and Edward Tatum (1909-1975). By 1940, however, some scientists believed Moewus's data to be statistically improbable--too good to be true. Moewus was accused of selecting only the data that fit his theoretical models, or perhaps of making up his experiments altogether...