In genetic research of the first decades of the 20th century women's work became a substantial resource. Women worked at different positions in scientific institutions; as independent scientists, wives of leading scientist, and as technical or other assistants. Male and female scientists had different opportunities to draw on the workforce of others; mostly women were doing the routine experimental work in the laboratories. This difference was crucial for the scientists' choice of experimental systems. To interpret the contributions of men and women scientists to the development of genetics these gendered differences in their working conditions have to be taken into account. Some examples of such interpretation are given in the article.
The case of the US group around Thomas Hunt Morgan that the existing historiographic literature is blind to the importance of gender for the functioning and success of the group. For the case of the Berlin group of Nikolaj Timofeeff Ressovsky a combination of several types of primary sources is used to explain the group's power to deal with the "big questions" of genetics, mutation research, and evolutionary theory in the 1920s and 1930s based on the work force of women assistants. The comparison of the group's work with that of the contemporary geneticist Paula Hertwig in the same field of mutation research indicates an important difference at the level of experimental systems, which was due to the different ranks of male and female scientists. A comparison of Paula Hertwig with other women geneticists of her time in Berlin illustrates the common situation of these womenpioneers, as they did not gain access to secure institutional positions and experimental systems at a large scale when genetics became a respective field in science. It is suggested that further comparison of women's and men's experimental systems and scientific careers may lead to interesting new insight into the dynamics of genetic science.
