clustering of mutations within an EMS mutated population?

[Gary Vanzin]

Has anyone experienced a clustering of mutations within an EMS mutated 
population?  The seven alleles I'm sequencing have shown unique 
mutations, all within 400 bases of each other (in a 1.2Kbp gene).  My 
only idea is that the gene may be highly expressed during the time in 
which the EMS is doing it's job, leaving the gene easily mutated within 
a certain region.  Any Ideas?