Q1. Limb development is caused by a number of integrated processes that form the patterns that tell which type of cell to grow in specific locations. Limb malformations caused by defects in limb development has been studied for a long time, even before DNA techniques were invented, because malformations are relatively easy to see and describe. Subjects/patients in studies of limb malformations are likely found through doctors offices and connections with medical professionals and the scientists that study these disorders. Information regarding the genetic regulation of limb development, or how cells are told what to do, is of interest to many people, including medical professionals, scientists,  and people who are affected by limb defects.

Q2. It is difficult to answer the question “what big processes are involved in the development of the human limb?” because of the complexity of this process as well as the ethical constraints of human research. Mice models are often used to decrease the later. The complexity of the system that allows limb development is a challenge for sure, but with carefully constructed studies using animal models it is possible to understand this process.