Not only do you need all of your organs, you need them all in the proper proportion. How does one segment of the vertebra know how big to get compared to another? Now we can see the spine growing in incredible glowing waves.
Scientists at the European Molecular Biology Laboratory (EMBL) took a look at the problem of how the body develops. It’s not enough to form a spine. A spine has to form in proportion to the rest of the body. And because the spine forms segments, each segment also has to form in proportion to the next segment.
To understand how organs grow, they decided to get genes to light up when they’re being expressed. (Expression is the translation of the gene from information to the actual meat bits that make up the body.) What they found was repeated “oscillations” of gene activity. These waves of gene expression moved through the tissue again and again. The speed of the wave movement was what determined the size of the vertebrae. As the wave gets faster, the vertebra gets bigger. So by varying the speed of pulses slightly, the embryo can vary the size of the object it’s building.