The Development and Evolution of Cartilage

Cartilage is one of the two principal tissues of the vertebrate skeleton (the other being bone). In mammals and birds, cartilage functions predominantly as a template for the endoskeleton, being largely replaced by bone, and persisting permanently at relatively few sites within the adult skeleton (e.g., at joints, as articular cartilage). However, in some fishes, cartilage or cartilage-like tissues may persist as a substantial feature of the adult skeleton. Here, I summarize the nature, distribution and function of cartilage within the vertebrate skeleton. I then review molecular mechanisms underlying the development and growth of vertebrate cartilage. Finally, I outline the phylogenetic distribution and diversity of cartilage within and outside of vertebrates, in order to emphasize the pre-vertebrate evolutionary history of this important skeletal tissue.