The essence of the developmental biology is to understand how the blueprint in the genome is implemented to build a complex multicellular organism. "Ming-boggling" questions such as regarding the formation of a vast and complex neuronal structure of human brain can be approached by first trying to understand the formation of the nervous system in fruitfly Drosophila -- a relative simple experimental organism amenable to sophisticated genetic and molecular analysis.

The stereotyped three dimensional structure of the Drosophila central nervous system is derived from a two dimensional neuroectodermal cell layer. The neuronal precursor cells called neuroblasts divide asymmetrically in a stem-cell-like mode for 5 to 10 times, producing a neuroblast and a ganglion mother cell in each step. A ganglion mother cell gives rise to two postmitotic neurons or glial cells, forming about 350 neurons and 30 glial cells per hemisegment. We will use genetic method to identify and use molecular biology to clone genes controlling these processes. We will study how these gene products function by using a combination of transgenic, genetic, molecular biological and biochemical methods. In addition, the entire Drosophila genome will be sequenced by the end of 1999, novel approaches, such as the gain-of-function genetics, RNA-interference and bioinformatics, will be explored for assigning functions to sequences in the exciting post-genome era.