Muriel Wheldale, a distinguished graduate of Newnham College, Cambridge, was a member of William Bateson's school of genetics at Cambridge University from 1903. Her investigation of flower color inheritance in snapdragons (Antirrhinum), a topic of particular interest to botanists, contributed to establishing Mendelism as a powerful new tool in studying heredity. Her understanding of the genetics of pigment formation led her to do cutting-edge work in biochemistry, culminating in the publication of her landmark work, The Anthocyanin Pigments of Plants (1916). (...) In 1915, she joined Frederick Gowland Hopkin's Department of Biochemistry as assistant and in 1926 became one of the first women to be appointed university lecturer. In 1919 she married the biochemist Huia Onslow, with whom she collaborated until his death in 1922. This paper examines Wheldale's work in genetics and especially focuses on the early linkage of Mendelian methdology with new techniques in biochemistry that eventually led to the founding of biochemical genetics. It highlights significant issues in the early history of women in genetics, including the critical role of mentors, funding opportunities, and career strategies. (shrink)