How did the characteristic pattern of embryonic cell divisions during animal development evolve? Analysis of the multicellular development of an organism related to animals now provides some answers.

Animal embryos go through a series of characteristic developmental stages on their journey from a fertilized egg cell to a functional organism. This biological process is largely genetically ...

Embryo development starts when a single egg cell is fertilized and starts dividing continuously. Initially a chaotic cluster, it gradually evolves into a highly organized structure. Scientists have ...