MONDAY, 4 MAY 2020
When a pre-natal test suggested that her second child could be born with severe chromosomal abnormalities, Professor Magdalena Zernicka-Goetz, a scientist at the University of Cambridge who has spent decades studying the process of mammalian embryonic development, realised that her scientific research and her personal life had become intertwined in a way that she could never have foreseen. Now in a new book, co-authored by Roger Highfield, Zernicka-Goetz gives us an introduction to contemporary embryology and an insight into her life as a scientist at the forefront of current research.
Like other mammals, both mouse and human embryos develop inside the body of the mother making them particularly difficult to study. In addition, unlike the embryos of ‘simpler’ species such as frogs, flies and nematode worms, which develop in a predictable manner according to a plan, mammalian embryos show remarkable plasticity. For example, even if cells of an early mouse embryo are removed or re-positioned, development can continue, and a normal adult mouse can be formed. This flexibility, alongside the hidden nature of in-utero development, makes mammalian embryology all the more enigmatic.
Zernicka-Goetz describes how she became fascinated by developmental plasticity after learning that the fate of embryonic cells could not be predicted – ‘it seemed risky for nature to leave the beginning of life to the mercy of randomness’. At the time, it was assumed that this plasticity meant all cells of the early embryo must be identical. With her colleagues in Cambridge she used techniques such as cell marking and live imaging to follow individual cells as the embryos developed. Her results were highly controversial. Rather than cell fate being random, her results detected that cells of the 4-cell embryo were biased towards forming particular cell types, suggesting that the cells of the early embryo were not exactly the same.
Zernicka-Goetz also describes the backlash she received from the scientific community at the time, as a young researcher who dared to challenge prevailing dogma. This was an experience she describes as the most difficult of her scientific life. Yet, despite the troubles faced in her early career, Zernicka-Goetz always found joy in scientific discovery. She, along with her team of post-docs and students, went on to make many further remarkable advances including the perfection of culture methods that can extend mouse and human development in-vitro up to the 14-day legal limit, and the creation of model embryo-like structures using stem cells. These advances have had dramatic clinical implications, particularly for researchers interested in developing fertility treatments or understanding why pregnancy failure occurs and how these could be prevented.
Zernicka-Goetz recounts how her science and her personal life became intertwined even more closely when pregnant with her second child. Through chorionic villus sampling, a type of pre-natal test that involves taking a sample of cells from the placenta, the foetus was diagnosed with a high risk of severe chromosomal abnormality. Her son was born healthy; however, this personal experience shaped her research for years to come as she set about trying to understand how embryos cope with abnormal cells, in the hope that this may one day benefit couples who find themselves in a similar situation.
The Dance of Life concludes by discussing the societal and ethical implications of embryological research, whilst at the same time stressing that, for Zernicka-Goetz, unravelling the mysteries of development is intellectually captivating and personally rewarding in its own right.
Hannah Mudge is a laboratory technician in the Department of Physiology, Development and Neuroscience.