During the past few decades, technical and conceptual breakthroughs have led to a virtual revolution in developmental biology. In part through cross-species compa- sons and multidisciplinary approaches (combining, for example, classical embry- ogy, genetics, molecular biology, and systems biology), major questions have often been redefined and examined from new angles and with innovative tools. Analyses using such model systems as Drosophila, Xenopus, zebrafish, chick, human, and mouse have underscored the remarkable extent to which molecular and genetic pa- ways are conserved across species...

During the past few decades, technical and conceptual breakthroughs have led to a virtual revolution in developmental biology. In part through cross-species compa- sons and multidisciplinary approaches (combining, for example, classical embry- ogy, genetics, molecular biology, and systems biology), major questions have often been redefined and examined from new angles and with innovative tools. Analyses using such model systems as Drosophila, Xenopus, zebrafish, chick, human, and mouse have underscored the remarkable extent to which molecular and genetic pa- ways are conserved across species...