Despite tremendous advances in knowledge of most of the organs in our bodies, tendons largely remain a mystery. Yet tendons are implicated in a number of disorders, including over 400 that are characterized by congenital joint contractures. A condition known as arthrogryposis multiplex congenita. The aim of this research is to gain insight into various aspects of tendon biology and development, including how tendons can molecularly be distinguished from other tissues, what the distinct stages of tendon development are, how tendon progenitors transition from one developmental stage to the next, and what distinct cell populations exist in the tendon.