How to get ahead: the origin, evolution and function of bicoid.
In Drosophila, a Bcd protein gradient orchestrates patterning along the anteroposterior embryonic axis. However, studies of basal flies and other insects have revealed that bcd is a derived Hox3 gene found only in higher dipterans. To understand how bcd acquired its role in flies and how anteroposterior patterning mechanisms have evolved, I first review key features of bcd function in Drosophila: anterior localization and transcriptional and translation control of gene expression. I then discuss investigations of bcd in other higher dipterans that have provided insight into the evolution of regulatory interactions and the Bcd gradient. Finally, I review studies of Drosophila and other insects that address the evolution of bcd function and integration of bcd into ancestral regulatory mechanisms. I suggest further comparative studies may allow us to identify the intermediate steps in bcd evolution. This will make bcd a paradigm for the origin and evolution of genes and regulatory networks.
McGregor
Alistair P
AP
Department of Ecology and Evolutionary Biology, Princeton University, New Jersey 08540, USA. amcgrego@princeton.edu
D000818:Animals; D019521:Body Patterning; D004175:Diptera / Q000196:embryology / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins; D019143:Evolution, Molecular; D018398:Homeodomain Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D015534:Trans-Activators; C056478:bcd protein, Drosophila