Rosa Beddington

freely distributed and have been invaluable resources Rosa Beddington died on May 18, 2001; she was to the community. just 45. Rosa moved again, in 1993, to take up the position Rosa was an embryologist of the greatest distinction; of Head of the Division of Mammalian Development at she had extraordinary technical skills, a piercing intellithe Medical Research Council’s National Institute for gence, and an artist’s intuitive view of the problem she Medical Research at Mill Hill, on the outskirts of London. worked on. Combined with the ability to meld together Within a year of her arrival, a paper appeared in Developthe approaches of classical embryology and modern ment, with Rosa as sole author. It showed that the node molecular genetics, these qualities allowed her to make of the mouse embryo could, when transplanted, induce many significant contributions during her career. She a second neural axis, thus establishing the functional also had a profound influence on the work of others. relationship between the mouse node and Spemann’s Rosa grew up in rural southern England where she organizer in amphibia and Hensen’s node in birds. She excelled at school, not only academically but also in noted briefly that anterior neural structures were not sport and at art, which might have been her career. Her present in the induced axes. Two years later, Rosa and childhood was not always happy and this influenced her an Australian postdoctoral fellow, Paul Thomas, showed attitudes in later life. She went to Oxford as an underthat the anterior visceral endoderm, a tissue previously graduate intending to pursue a career in medicine but thought to serve a nutritive or protective function, is decided that this was not for her. In 1977, she began patterned at the time of primitive streak formation. Reher research work as a graduate student in the Sir Wilmoval of these endodermal cells disrupts the patterning liam Dunn School of Pathology, working with Ginny Paof the underlying ectoderm and thus, the formation of paioannou, where, from the beginning, she focused on the most anterior CNS. The discussion of this paper finds central questions: which cells in the early mouse embryo Rosa in her most magisterial form as she reinterprets the give rise to which tissues and how are such decisions data of others in support of her hypothesis. The marker controlled? And from the beginning her experimental used in these experiments was the expression of the dexterity was apparent: in her third paper she reported Hesx1 gene that Rosa and her colleagues subsequently a technique for transplanting early postimplantation emshowed is required for normal forebrain development in bryos from their mother to another pregnant mouse. All mice and humans. They subsequently went on to show who have struggled to learn how to dissect such an that another diverged homeobox gene, Hex, had an even embryo from its deciduum without damaging it, let alone more provocative expression pattern. Hex expressing to transplant it so that it can continue growth and develcells are found in the endoderm at the distal tip of the opment, wonder at how she did it. After completing