In vitro systems: A new window to the segmentation clock

Segmental organization of the vertebrate body plan is established by the segmentation clock, a molecular oscillator that controls the periodicity of somite formation. Given the dynamic nature of the segmentation clock, in vivo studies in vertebrate embryos pose technical challenges. As an alternative, simpler models of the segmentation clock based on primary explants and pluripotent stem cells have recently been developed. These ex vivo and in vitro systems enable more quantitative analysis of oscillatory properties and expand the experimental repertoire applicable to the segmentation clock. Crucially, by eliminating the need for model organisms, in vitro models allow us to study the segmentation clock in new species, including our own. The human oscillator was recently recapitulated using induced pluripotent stem cells, providing a window into human development. Certainly, a combination of in vivo and in vitro work holds the most promising potential to unravel the mechanisms behind vertebrate segmentation.

Automated summary

The segmentation clock, a molecular oscillator controlling vertebrate body plan segmentation, poses technical challenges for in vivo studies, but simpler ex vivo and in vitro models offer more quantitative analysis of oscillatory properties and expand experimental approaches. By using in vitro models, we can study the segmentation clock in new species, including humans, offering insights into human development mechanisms. A combination of in vivo and in vitro work holds the most promising potential to unravel the mechanisms behind vertebrate segmentation.