John J Young
My lab uses the frog Xenopus laevis as a model to study the molecular genetics that give vertebrates their shape, patterns, and diversity. Work in my lab focuses on two major areas of development: neural patterning and amphibian limb development. First, our questions about neural patterning center on how extracellular signals determine where the brain and the spinal cord form in the central nervous system. Much is known about the signaling molecules that regulate this process. Much less is known about how these signals are interpreted into positional identity at the cellular level. To unravel this process, we use genome-editing techniques to generate a “wiring diagram” that integrate the extracellular signals with gene expression. Secondly, we look at how the frog embryo initiates limb development during the transition from tadpole to froglet. Much investigation of amphibian limbs has centered on regeneration, however, this has identified a major gap in our knowledge of the developmental origins of the limb itself. Our current model of vertebrate limb development comes from the study of amniotes (mammals, birds, and reptiles), where the limbs are present and mostly functional at birth or hatching. These animals build their limbs from defined tissues only present in the embryo, which interact to differentiate into the skeleton, muscles, and neurons of the limb. Little is known about how a similar limb is built when those embryonic tissues are no longer present, as is the case in a tadpole. To address this question we use a combination of molecular and classical embryology to determine the origins of the amphibian limb and the genetic mechanisms that govern its development.