Watching Genes Build a Body
Gretchen Vogel
The human genome is touted as the master plan for building an organism. But it is up to developmental biologists to decipher how that "master plan" directs construction.
Traditionally, developmental geneticists have learned how genes control development by altering a gene and observing what goes wrong in model organisms such as the fruit fly Drosophila melanogaster, the nematode worm, and the mouse. Complete genomes --the fly, worm, and human are now finished--have simplified the process of locating genes that cause intriguing abnormalities.
CREDIT: ILLUSTRATION: CAMERON SLAYDEN
But the genomes will also have a more profound effect. Genomics "has completely revolutionized how I think about developmental biology," says Stuart Kim of Stanford University. That's because researchers can now take whole-genome snapshots of cells and tissues, instead of investigating one gene at a time. Kim and his colleagues have completed 800 microarray experiments recording the relative activity of nearly every worm gene at different developmental stages, in different body parts, and under different conditions. The result, Kim says, is a wealth of information about each of those genes. The problem now is how to make sense of the data avalanche--the team has yet to sort through the nearly 2000 genes that are turned on during development of the genitals, for instance.
Other researchers plan to conduct similar studies on human cells. For example, the biotechnology company Geron, based in Menlo Park, California, has signed an agreement with Celera Genomics in Rockville, Maryland, to analyze which genes are switched on in human embryonic stem cells, the prized cells taken from early embryos that can develop into any cell type. Following gene activity while the cells are still undifferentiated and as they develop into certain tissue types could reveal "the essence of being a stem cell," says Kim.
