In article <3tt7k3$o0i at news.unimelb.EDU.AU> julia <juliam at ariel.ucs.unimelb.edu.au> writes: > looking for. Now what I am seeing on these gels is one band only. Sounds if your probes are contaminated with PCR product from one allel. Burkhard Hassel (bhassel at orion.rz.mdc-berlin.de)