"The instructions for development have to be in the genome somewhere, but you would be surprised how fragmentary the information about how that works was until we did this system-level analysis," says Davidson. "You can never understand it by looking at one gene. You can never understand it by looking at a third of the genes. You really have to get the whole system mapped outand that's what we did."
In 2008, Davidsonwho has been studying the biological processes of sea urchins for many yearsled a research team that sketched a rough outline, for the first time, of how the GRN works to produce the sea urchin's skeletal system. "We are light-years beyond that with this new study," he says. "That was about solving network subcircuits, but now we have a framework that causally explains the far more complex process of development required for gut formation in terms of the genome's regulatory instruction code." This advance opens a much larger range of developmental scenarios to causal network analysis.
Sea urchins' gene regulatory systems, Davidson points out, are the closestamong the thoroughly studied invertebrate systemsto those of mammals, in terms of evolutionary relationships. This means the mechanisms the team uncovered in their work are likely to illuminate our own developmental regulatory systems. This could have implications for human health.
"If you believe that medicine consists of putting Band-Aids on things, then we have no relevance to that," says Davidson. "But if you believe that we should understand how life works before trying to find a cure when something goes wrong, then understanding biological processes from their initial stages comes first."
The team would next like to take their framework analysis and apply it to later stages in developmentto when the gut is actually present. "We would like to understand how the different compartments in the g
|Contact: Deborah Williams-Hedges|
California Institute of Technology