Muscle fibres, Drosophila embryo

Pattern of muscle fibers in a Drosophila embryo. Muscles, but no other tissues, were engineered to express a green fluorescent protein (GFP) that is visualised here in green. During embryogenesis minuscule muscle fibers develop into a regular pattern. At this stage (embryo stage 17), embryos normally initiate contraction waves in order to leave the egg shell. Image width is 461 micrometers.