My favourite scientific quotation: “From the egg, all” would be an apt motto for a women’s college in the 21st century but was actually immortalised by the famous Cambridge physician William Harvey almost four hundred years ago as the Latin epigraph “Ex ovo omnia”. As a developmental biologist, I share Harvey’s fascination with embryology, the process by which a fertilised egg develops into a precisely patterned organism. Fortunately for me, there have been phenomenal advances in social attitudes and scientific techniques since Harvey’s era: women are now active members of the scientific research community and astounding recent technical developments have provided us with experimental tools to investigate the genesis of life.
I became intrigued by developmental biology as an undergraduate at Cambridge, inspired by some lecturers who used frogs as a model organism to understand developmental processes. Frog eggs are large and externally fertilised, allowing scientists easy access to the vital first stages of embryogenesis, when the fertilised egg cleaves into a ball of cells, which look similar to each other but have already taken on distinct identities and will ultimately go on to form different embryonic structures. The aim of developmental biologists is to understand the regulatory mechanisms that give rise to the multitude of cell types in an adult organism. Some key developmental genes identified in amphibian studies cause inherited human birth defects and many frog labs receive medical research funding.
Science is an international endeavour so scientists often go to different labs to gain specific research expertise. I joined frog labs in Canada and the U.S. before returning to Cambridge. The opportunity to live in different countries within an international community of scholars and to attend international meetings and field trips is a great benefit of a career in academic science.
I twice went to Puerto Rico to collect coqui frogs; these are nocturnal tree frogs that live in the rainforest and we collected at night, leaving the days free for sightseeing! Coqui are direct developing frogs, hatching as tiny froglets. I discovered that though they don’t have a free-living tadpole, coqui embryos undergo a cryptic metamorphosis in the egg.
Recently, I have applied my knowledge of developmental signalling processes to coax stem cells down a particular developmental route, making the endothelial cells that line blood vessels. Such “directed differentiation” holds great promise for regenerative medicine. However, the practical aspect is hugely laborious as stem cells require daily nurturing, including weekends and holidays!
Currently, I am nurturing another organism, my four-year-old son, though I still participate in the scientific process by writing scientific articles with my colleagues in the Department of Medicine. I co-ordinate the science/technology strand of our Gateway Academic Development Programme at Murray Edwards, helping freshers transition to university learning, and I’ve participated in a variety of science outreach events. As a Director of Studies and a Tutor, I interact with many students and am amazed by the resourcefulness of our STEMM students, who demonstrate that a scientific education provides a versatile skill-set for life.
Dr Liz Callery
Fellow, Director of Studies and Tutor