The gene-regulatory evolution of the human skeleton.

Gene-regulatory changes in over 15,000 loci drove extensive remodeling of the human skeletal extracellular matrix, including a three-to-fourfold reduction in joint GAG content.

• Why it matters: Understanding the genetic basis of skeletal evolution is crucial for insights into human-specific traits and diseases, yet the regulatory changes underlying these adaptations remain largely unknown.
• What they did: Using massively parallel reporter assays in chondrocytes and human-ape hybrid cell models, researchers mapped human-specific regulatory activity across 561,410 substitutions, creating genome-wide atlases of cis-regulatory changes.
• The result: The findings reveal a coordinated evolutionary shift in the skeletal extracellular matrix, likely contributing to human susceptibility to degenerative skeletal diseases and providing a framework for future genetic studies.