As a child you may have watched in awe as frog spawn gradually developed into tadpoles, which then morphed into frogs. The fact that this process is so easy to follow has made the African clawed frog – Xenopus laevis – a popular model organism for developmental biologists and genetics researchers. This species has had a distinguished scientific career – it was the first vertebrate to be cloned and has even been blasted into space. Pictured is a Xenopus laevis embryo. It’s just 12 hours old, but has already developed from a single fertilised egg to a hollow ball of thousands of cells, called a blastula. In the next stage of its amazing transformation, this ball of cells will take just three days to become a wriggling tadpole.
Written by Sarah McLusky
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.