That's Yet Another Thing To Look At!! This is from a dialogue on bionet.metabolic-reg 'Univeral format for storing pathways and models'. Gene Selkov ( at ANL) has a node-based graphical tool for constructing metabolic pathways. You might want to look at it. I thought it was interesting in the context of loci. http://www.xnet.com/~selkovjr/ElectricArc/ -- .david David Lapointe Do Not Attribute To Malice That Which Can Be Attributed To Stupidity