Homeodomains, Hedgehogs, and Happiness.

ABSTRACT

Developmental biologists have had a spectacular quarter century of discoveries, building on many decades of work earlier, discovering molecular, cellular, and genetic mechanisms that underlie the magical process by which an egg becomes a plant or animal. Among the discoveries were homeodomains, DNA-binding domains that allow transcription factors to recognize their target genes, and the Hedgehog signaling pathway, which is used in many organs and tissues for communication among cells. The experience of unveiling the mechanisms and molecules connected to both of these findings has been remarkable, joyful, difficult, and a time of great teamwork and collaboration within and between laboratory groups. More than ever it is possible to discern the evolutionary processes, and their mechanisms, that led to the diversity of life on earth. A huge amount of work remains to be done to obtain a broad understanding of what happened and how development works.