From owner-drosophila@net.bio.net Fri Jan 28 22:00:00 1994 Path: biosci!bcm!cs.utexas.edu!howland.reston.ans.net!pipex!uknet!daresbury!not-for-mail From: "JMohler" Newsgroups: bionet.drosophila Subject: Activation/Inhibition Models (for head segmentation) Date: 28 Jan 1994 18:30:47 -0000 Lines: 23 Sender: daemon@mserv1.dl.ac.uk Distribution: bionet Message-ID: <2iblkn$iqm@mserv1.dl.ac.uk> Encoding: 1303 Text Original-To: reinitz-john@cs.yale.edu (John Reinitz), dros@net.bio.net John: I've been meaning to get in touch for a while. I was wondering if you had a program to model a Turing process to generate stripes. I hoping such would be a simple, naive model to explain how the cephalic segments (preanntennal, antennal and intercalary) are generated. Basically, the phenomenology is that both wg and hh are initially expressed in broad overlapping domains in this region (with the wg doamin slightly anter- ior to the hh domain). These domains gradually divvy up into three striped domains (actually for wg, two stripes and a "head blob"). It seems to me that the mutual interaction between hh and wg, coupled with the initial overlapping distributions, could generate such stripes. There is some consistent circumstantial evidence. For example, ems and otd mutants remove the hh and wg domains (respectively) early; the remaining wg or hh domain then remains as a single domain. Also, tll mutants cause the initial hh domain to extend anteriorly past the edge of the wg domain; then wg domain forms only two stripes without the "head blob". I'd like to see if one could generate a simple and dirty, mutual activation/inhibition model to account for this. IF you can help me at all, I'd appreciate hearing from you. Jym Mohler .