You’re looking into the developing eye of a fruit fly (Drosophila). Just like our own organs, the eye takes shape in a series of careful stages. All of its tiny cells (outlined in blue) once raced to divide and grow, but the red-centred cells have stopped – they’ve differentiated [specialised] into building blocks for the eye. A balance between growth and differentiation normally helps organs to develop correctly, but inside this eye something is wrong. Genes controlling the developmental ‘traffic lights’ have been disrupted – some of the differentiated cells have begun to divide and grow once again (coloured green, in the centre). This unfortunate fruit fly has many genes in common with us, providing clues about how cells in human tissues sometimes return to a neoplastic [re-growing] state, bringing a risk of cancer as they divide out of control.
Written by John Ankers
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.